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Rice straw hydrolysate produced in rice straw pretreatment, comprising a lot of fermentable sugars, is generally released into the environment. This not only causes environment pollution but also wastes fermentable sugars from rice straw. To alleviate environment impact, maximize ethanol production from rice straw, and reduce the cost of ethanol production, rice straw hydrolysate and NaOH-pretreated rice straw were converted to ethanol using ethanol-type fermentation and simultaneous saccharification and fermentation (SSF) by sludge. Meanwhile, microbial community in sludge was analyzed to find the relationship between ethanol production and microbial community succession during ethanol-type fermentation and SSF. Under the optimal condition of the COD, pH and oxidation–reduction potential (ORP) value of rice straw hydrolysate with 6280.56 mg/L, 6.7, and − 42 mV, ethanol-type fermentation with the sludge of 15 g obtained the highest ethanol concentration (8.34 g/L) and the highest COD removal rate (54.83%). For SSF, the maximum ethanol concentration (3.75 g/L) produced by pretreated rice straw and sludge from ethanol-type fermentation with the sludge of 15 g was higher than that (2.61 g/L) generated by pretreated rice straw and sludge from ethanol-type fermentation with the sludge of 22.5 g. This indicated that sludge from ethanol-type fermentation with the sludge of 15 g more efficiently converted rice straw to ethanol than sludge from ethanol-type fermentation with the sludge of 22.5 g. Microbial community analysis suggested that ethanol production had a negative correlation with the relative abundance changes of Bacteroidetes, when the relative abundance of Firmicutes constantly rose in ethanol-type fermentation and SSF. This study provides a scientific basis for maximizing ethanol production from rice straw by microbial regulation in sludge, which could further reduce the cost of ethanol production. [ABSTRACT FROM AUTHOR]

Rice straw is an abundant agricultural waste, especially in Asian countries, of which a large amount is still open burnt. This leads to the emission of greenhouse gases (CH4, N2O, etc.) causing huge environmental impacts and is a waste of a cellulose, lignin, and silica source, which are highly valuable compounds. In this work, nanocellulose (CNC) was produced from rice straw using chemical method, together with waste stream utilization. The acid waste from the hydrolysis and the black liquor from cellulose isolation were used to recover a hybrid material of lignin and silica (LS), which was then applied to remove methylene blue from water. CNC was prepared using acid hydrolysis presented as rod-like particles with a crystallinity of 85% and a diameter of 20–30 nm in width and 200–400 nm in length, which was of high quality and suitable for further applications. The LS hybrid performed well in adsorbing methylene blue in aqueous solution, with the trapping capacity of 68 mg/g. Subsequently, a pilot-scale integrated process to produce CNC and LS hybrid was proposed to reduce the chemical and water usage in treating waste stream and move towards the "zero-waste" concept and circular economy principle. The process is a possible solution for facile and feasible large-scale transformation of rice straw into value-added products. [ABSTRACT FROM AUTHOR]

Rice straw is a relevant and potential feedstock for bioethanol production due to its abundance and availability around the globe. In this study, a fractional factorial design (FFD 25–1) was applied to simultaneously evaluate the influence of only alkaline and acid-alkaline pretreatment conditions in glucose release, considering the glucose release after 12 and 24 h of enzymatic hydrolysis as responses and predicting alternatives for the fractionation of rice straw components. Hydrolysis yields (HY) higher than 90% were achieved using low enzyme loads (8 FPU/g substrate) after only 24 h of hydrolysis under optimized pretreatment conditions. Simultaneous DOE optimization showed that the acid step is optional to achieve higher HY but can contribute to a more holistic use of the hemicellulose fraction. Also, it significantly increased the hydrolysis efficiency compared to untreated rice straw (HY = 18%). Enzymatic hydrolysis with a different type of enzymatic cocktail in the optimized conditions using higher solid contents resulted in high cellulose conversion (up to 85%), showing the robustness of the DOE optimization and its applicability as a starting point for optimizations using other types of enzymes. Chemical and morphological analyses were also carried out to understand the effect of the treatments, aiming to achieve pretreatment and hydrolysis processes more effective for lignocellulosic biorefineries. [ABSTRACT FROM AUTHOR]

In the present study, rice straw‐derived cellulose was converted into carboxymethylcellulose (CMC) using alkalization followed by an etherification reaction. The synthesis conditions for this chemical modification were optimized such that CMC with a high degree of substitution (1.02) was obtained. Infrared spectra of the synthesized CMC clearly showed an increased intensity of the C═O bond at 1600 cm−1, confirming successful carboxymethylation. Further, X‐ray diffraction analysis demonstrated a decrease in cellulose crystallinity owing to partial rearrangement from a crystalline to an amorphous phase during initial alkalization reaction. The obtained CMC biopolymer was subsequently cross‐linked to form a composite hydrogel matrix reinforced with bentonite clay. The hydrogel showed about 91% adsorption capacity for methylene blue dye as a model contaminant in aqueous media. Therefore, this study shows that lignocellulosic agrowaste is a rich source of cellulose, and its derivatives such as CMC possess the potential to realize the waste to wealth sustainability goal. [ABSTRACT FROM AUTHOR]

Carboxylate appended biochar BCKA was synthesized by a two‐step functionalization of leached rice straw biochar using ethyl 2‐bromoacetate/K2CO3/DMF and hydrolysis to furnish the modfied biochar. The modified biochar was characterized using proximate analysis, CHNS, SS CPMAS 13C NMR, FESEM, FTIR, XPS, BET, and zeta potential. Biochar BCKA was optimized for pH and dose, respectively, as 7 and 0.2 g/L for methylene blue (MB) adsorption with a contact time of 6 h at 298 K. MB removal up to 98% from 20 mg/L dye solution, using BCKA as adsorbent pH 7, 298 K. The nonlinear fit to Langmuir, Freundlich, Temkin, SIPS, and D‐R adsorption isotherm showed a good fit with correlation coefficients (R2) 0.970, 0.969, 0.988, 0.984, and 0.983, respectively, and maximum MB adsorption (qm) of 261 mg/g. Thermodynamic parameters for the adsorption of MB using BCKA were 38.72 kJ/mol (∆H°), 225.42 J/mole K (∆S°), and negative ∆G° confirming the spontaneity driven by entropy. Kinetic studies showed good nonlinear fit to pseudo‐second order (R2 0.967), intraparticle diffusion (R2 0.977), and Elovich equation (R2 0.958) with chemisorption‐based interaction between BCKA and MB. Chemisorption, particularly ion exchange on the surface of BCKA with MB, is inferred from the D‐R isotherm and kinetic analysis. Column breakthrough studies showed Thomas model fit with qt 267.09 mg/g, and efficiency >80% was retained for two cycles of MB adsorption. [ABSTRACT FROM AUTHOR]

This work was focused on the manufacturing of strawboard from agricultural waste like wheat straw (WS) and rice straw (RS) as natural resources of fibre by a sustainable and eco-friendly approach. Pineapple crown waste (PCW) fibre was used to replace the binder chemicals that are being used in the strawboard manufacturing industries to improve their quality in terms of mechanical strength properties. The strawboard with admirable properties like 4.74 mN·m2/g tear index, 14.96 N·m/g tensile indexes, 1526 m breaking length, 8.87 burst factor, and 20.3 stiffness factor was developed by adding 40% of PCW with 60% of WS pulp which was prepared by hydrothermal treatment of the material at 165 °C followed by the refiner mechanical pulping of the material. In addition to that, blending 60% RS with the same quantity of PCW pulp could develop strawboard with similar properties as that of wheat straw, which met the grade A and grade B strawboard required specifications as per Indian Standard: 2647–1967. The step towards utilizing agricultural waste to develop chemical-free strawboard not only minimizes the dumping of waste into the open field but also reduced the chemical utilization by the strawboard manufacturing industries, with PCW fibre that has been measured about 43% and 48% longer than WS and RS fibre, these could be the main reasons for developing such kind of strawboard with high mechanical properties. The fibre quality (morphology, crystallinity, and functional groups) of the different materials used was verified by different characterization techniques, such as FE-SEM, XRD, and FTIR-ATR analysis. [ABSTRACT FROM AUTHOR]

The process of bioethanol production has several economic drawbacks such as the cost of enzymes, i.e., cellulase, which hydrolyze cellulose to produce fermentable sugars. In this study, to reduce the production cost of cellulase, agricultural wastes such as wheat straw (WS) and rice straw (RS) were used as carbon sources for cellulase production through solid-state fermentation. First, the standard cellulase production conditions were optimized, the initial moisture content of the solid medium was 60%, the biomass particle size was 100 µm to 4 mm size mixed, and the optimal carbon/nitrogen (C/N) ratio in the medium of WS and RS was 59.0 and 41.2, respectively. Subsequently, to simplify process handling, eliminating trace elements such as MgSO4, CaCl2, FeSO4, MnSO4, ZnSO4, CoCl2, and phosphorous compounds such as KH2PO4 in the general Mandel's medium was used for cellulase production medium and compared with the standard medium. Maximum 5.4 filter paper unit (FPU)/g-substrate (WS) and 5.3 FPU/g-substrate (RS) were attained under trace element eliminating medium; these were similar to that from the standard medium of WS (4.8 FPU/g-substrate) and RS (5.7 FPU/g-substrate). Moreover, the produced crude cellulases from RS were evaluated for their potential in hydrolysis of alkaline-treated RS. The performances of the crude cellulases were similar to those of commercial cellulases. [ABSTRACT FROM AUTHOR]

Background: Weed infestation in cotton has been reported to offer severe competition and cause yield reduction to a large extent. Weeding via cultural practices is time consuming, tedious, and expensive due to long duration of cotton crop and regular monsoon rains during cotton production in India. Chemical weed control has been successfully utilized in cotton in the recent past. However, continuous use of similar herbicides leads to resistance in weeds against herbicides. And when sprayed to the field, herbicides not only suppress weeds but leave undesirable residues in the soil that are hazardous to the environment. Therefore, a study was performed at cotton research area at Chaudhary Charan Singh Haryana Agricultural University, Hisar, Haryana during two consecutive kharif seasons (2020 and 2021) to determine the most suitable and sustainable weed management strategy through the integration of chemical and cultural methods. Results: Mulching with rice straw of 7.5 t ha−1 resulted in significantly higher cotton seed yield (3 189 and 3 084 kg ha−1) and better weed control in comparison to no mulch treatments (2 990 and 2904 kg ha−1) in 2020 and 2021, respectively. Among various weed management levels, the significantly lowest cotton seed yield was recorded in untreated control (1 841 and 1 757 kg·ha−1 during 2020 and 2021, respectively) in comparison to other treatments while all other treatments were statistically at par with each other during both years of crop experimentation. Conclusion: Mulching with rice straw of 7.5 t·ha−1 along with a pre-emergence application of pendimethalin (active ingredient) at 1.5 kg·ha−1fb (followed by) one hoeings at 45 days after sowing (DAS) and fb glyphosate 2 kg·ha−1 (Shielded spray) at 90 DAS is a viable option for effective control of grassy and broadleaved weeds in Bt cotton in north-west India. [ABSTRACT FROM AUTHOR]

The physiochemical pretreatment was performed using different concentrations of oxalic acid (OA) as a simultaneous pretreatment and saccharification (SPS) process on rice straw to obtain reducing sugar from two‐phasic SPS process using enzymatic and acidic hydrolysis to subsequently ferment to bioethanol in order to maximize the yield of bioethanol. The optimal condition for pretreating rice straw using 0.5, 0.75, 1, and 1.5 M OA at 120°C for 1 h was evaluated. The morphological and structural changes after simultaneous pretreatment and SPS process were evaluated using Fourier‐transform infrared (FTIR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and field‐emission scanning electron microscopy (FESEM) analysis. It was evaluated that optimum pretreatment conditions using a lesser concentration of OA had resulted in 30.37% of xylan removal from pretreated rice straw obtained after simultaneous pretreatment and SPS process. The ethanol production yield ranged from 0.42 to 0.37 g/g with fermentation efficiency of up to 57.18% and an overall ethanol production yield of 42.84% from the obtained hydrolysate of the two‐phasic SPS process. The highest ethanol concentration from the obtained hydrolysate was produced at 120°C for 1 h with 0.75 M OA; under this condition, maximum degradation of utilized lignocellulosic biomass takes place. [ABSTRACT FROM AUTHOR]

The inherent complexity of cellulose, hemicellulose, and lignin contributes to the recalcitrance of lignocellulosic biomass, resulting in a low conversion efficiency and high cost of bioethanol conversion. Pretreatment methods that disrupt the plant cell structure of lignocellulose, such as straw, can significantly enhance the conversion efficiency. In this study, we utilized an acid-assisted mechanocatalytic depolymerization technique to pretreat rice straw, and the results demonstrated a significant disruption of the cellulose structure of the straw. Compared to the untreated straw, the particle size of pretreated straw reduced from 279 μm to 11.8 μm, the crystallinity of cellulose decreased from 43.05% to 22.71%, the specific surface area increased by 177%, and the surface oxygen-to-carbon ratio (O/C) ratio was enhanced by 75%. The changes in microstructure enabled the pretreated straw to achieve a total sugar yield of over 95% within 12 h of enzymatic hydrolysis, significantly superior to the 36.24% yield from untreated straw, the 45.20% yield from acid impregnated straw, and the 73.25% yield from ball milled straw. Consequently, acid-assisted mechanocatalytic depolymerization emerges as a highly effective pretreatment strategy to enhance both the enzymatic hydrolysis and the overall conversion efficiency of rice straw. [ABSTRACT FROM AUTHOR]

To explore the specific effects of pig manure and rice straw on cadmium‐contaminated soils and the effect of different mass fractions of calcium carbonate on cadmium efficacy, a pot experiment was conducted with different rates of pig manure, rice straw, and calcium carbonate. The results showed that pig manure addition increased the soil humic acid/fulvic acid ratio, thereby reducing the available Cd. The addition of calcium carbonate increased the soil pH and reduced the available Cd. The addition of pig manure and calcium carbonate significantly reduced the Cd content of wheat grains by 51.96% and 45.95%, respectively, at 3% and 5% application rates. Rice straw application reduced the soil pH, improved the soil Cd availability, and increased the accumulation of Cd in wheat grains. Compared with that in the control, the grain biomass increased significantly with 3% pig manure and 3% rice straw application, and the grain biomass increased significantly, by 58.86% and 39.11%, and 93.3% and 75.08%, respectively, in 2020 and 2021. With the application of calcium carbonate, the grain biomass of wheat first decreased and then increased. Additionally, the grain biomass significantly increased by 26.36% and 71.22%, respectively, at the 5% calcium carbonate application rate. Therefore, high application rates of pig manure (3% and 5%) have potential application in the safe production of wheat in Cd‐contaminated soils. Core Ideas: The increase in soil humic acid/fulvic acid was the main reason for the reduction in diethylenetriaminepentaacetic acid‐extractable Cd in pig manure‐treated soils.The increase in pH was the main reason for the inhibition of soil Cd by calcium carbonate, and rice straw promoted.The application of pig manure and calcium carbonate increased wheat biomass and inhibited Cd uptake by wheat.The application of pig manure and calcium carbonate increased wheat biomass, inhibited Cd uptake by wheat.Pig manure with a low Cd content has potential for application in the safe production of wheat in Cd‐contaminated soils. [ABSTRACT FROM AUTHOR]

We studied the allelopathic effects of mulch and aqueous extracts of Rice (Oryza sativa L.) straw and on growth of 8-weeds: Phalaris minor L., Cynodon dactylon L., Chenopodium album L., Rumex denticulate L., Anagalis arvensis L., Melilotus spp L., Parthenium hysterophorus L. and Cyperus rotundus (L.) was analyzed. Rice straw mulch at 4.0 t/ha and rice aqueous solution (10 g/L) spray significantly reduced these weeds density (Number/m2) (54, 55, 66, 79, 85, 73, 54 and 39 during 2020-21) respectively, than control. Rice straw mulch 4 t/ha followed by (metsulfuron methyl 4 g a.i./ha + clodinafop propargyl 60 g a.i./ha) and clodinafop propargyl 75 % of 60 g a.i./ha + rice aqueous solution (10 g/L) spray significantly reduced the density of test weeds. Density of grass weeds decreased in zero-till, but broad leaved weeds decreases in conventional tillage. Wheat growth (dry matter accumulation: g/plant), number of tillers per m, leaf area index (LAI) and yield) significantly increased by rice straw mulch at 4 t/ha followed by rice aqueous solution (10 g/L) spray than control. [ABSTRACT FROM AUTHOR]

This paper presents a novel method of treating high water content dredged slurry by vacuum pre-pressure using woven rice straw as horizontal drainage boards (SHDs). This not only helps to avoid the impact of plastic drainage boards on the environment, but also helps to utilize agricultural related waste. The study aimed to investigate the effect of SHDs degradation on the vacuum transfer within the horizontal drainage boards and the consolidation characteristics of dredged slurry. Indoor vacuum preloading model tests were conducted to investigate soil settlement, straw degradation, vacuum variation and water content distribution within the drainage board. The results show that SHDs can significantly improve the consolidation of dredged slurry. The closer the straw is to the interface between the drainage board and the vacuum pipe, the greater the degree of degradation. The water content was distributed with depth in an oblique "z" shape, while a point with higher water content existed at 1/3 of the soil above the drainage boards. In addition, the low water content zone around the drainage board shows an elliptical shape due to the influence of gravity. These research results have some reference value for the ecological treatment of dredged slurry and straw. [ABSTRACT FROM AUTHOR]

Construction is one of the economic sectors with the greatest influence on climate change. In addition to working procedures, the primary carbon footprint is attributed to the choice of materials and the energy required for their manufacturing. The underlying idea of this study is to minimize the effects and offer new solutions to emerging problems in the quest for materials that can be deemed as natural, such as gypsum (calcium sulphate dihydrate) and rice straw (Oryza sativa). The acquisition of these materials involves a lower carbon footprint compared to the conventional materials. It is well known since ancient times that gypsum and cereal straw can be used in construction, with numerous examples still available. Cereal straw is one of the oldest construction materials, traditionally combined with earth and occasionally with certain binders, with it continuing to be employed in construction in many countries to this day. This work showcases the feasibility of producing stable prefabricated elements from straw waste with construction gypsum, addressing a significant environmental concern posed by the alternative of having to burn such materials. In this study, for the proposed bio-based material, specific tests, such as thermal conductivity, flexural and compressive strength, and fire resistance, were carried out to evaluate the principal physical and mechanical characteristics for different compositions of water, gypsum, and straw fiber samples. The results highlighted the good performance of the proposed materials in order to spread their use in the green building industry. The addition of straw fibers improved, in different ways, some important physical characteristics of these components so as to diminish environmental pollution and to obtain better material performance. The tests highlighted the different behaviors of the proposed material with respect to the different cuts of the straw and as well as the water/gypsum ratio; this is not very well understood and probably depends on the micro structure of the straw fibers. The blocks with raw straw showed a significant improvement in the breaking mechanism (1775.42 N) compared to the blocks with cut straw (712.26 N) when subjected to bending tests, and their performance in compression tests was also acceptable. Additionally, a very interesting reduction in thermal conductivity was achieved by incorporating rice straw (0.233 W/mK), and high fire exposure times were obtained, with gypsum preventing the spread of ignition in any type of fiber. [ABSTRACT FROM AUTHOR]

The purpose of the current research was to evaluate the influence of lactic acid bacteria and cellulase supplementation on the chemical composition, fermentation parameters, aerobic stability, microbial count, and in vitro nutrients digestibility of silage prepared with Pennisetum giganteum and rice straw. This study consisted of four treatments: a control group with no additive supplementation (CON), a lactic acid bacteria supplementation group (LAB), a cellulase supplementation group (CEL), and a combined supplementation group (LAC). After ensiling for 60 d, the chemical composition, fermentation parameters, microbial count, and aerobic stability were determined. Additionally, ruminal fermentation characteristics were evaluated by an in vitro incubation technique. Compared with CON silage, the quality of LAB and CEL silages was enhanced to a certain degree. Combined supplementation with lactic acid bacteria and cellulase in mixed silage of Pennisetum giganteum and rice straw noticeably increased (p < 0.05) the dry matter, crude protein, and lactic acid contents, whereas it reduced (p < 0.05) the pH and ammonia nitrogen/total nitrogen as well as the neutral detergent fiber and acid detergent fiber concentrations. The lactic acid bacteria count in LAC silage was higher (p < 0.05) than that of CON silage, whereas an opposite trend of yeast, aerobic bacteria, and mold was observed between the two groups. The aerobic stability time, in vitro crude protein, and neutral detergent fiber digestibility in LAC silage were significantly increased (p < 0.05) compared with those in CON silage. Moreover, the in vitro ruminal ammonia nitrogen content was reduced (p < 0.05), and the microbial protein and propionic acid concentrations were increased (p < 0.05) in silage after combined inoculation with additives. Taken together, the quality of Pennisetum giganteum and rice straw mixed silage can be improved by inoculation with lactic acid bacteria and cellulase, and combined supplementation shows the greatest improvement in silage quality. [ABSTRACT FROM AUTHOR]

The objective of this study was to explore the rumen fermentation characteristics, bacterial diversity, community composition, and metabolite profiles of rice straw from three distinct varieties. Straws from two hybrid rice varieties, Lingliangyou 268 (L268) and Yueyou 9113 (Y9113), and one inbred rice variety, Zhongzao 39 (Z39), were selected for a 72 h in vitro rumen fermentation test. The fermentation products were analyzed for rumen fermentation characteristics, bacterial community, and rumen metabolomics. The results showed that Y9113 had higher total gas and methane production, greater dry matter digestibility, and higher concentrations of ammonium nitrogen and volatile fatty acids compared to Z39 (p < 0.05). The variety of rice straw did not affect the richness or diversity of the rumen bacterial community (p > 0.05). However, the relative abundances of Verrucomicrobiota, Euryarchaeota, Elusimicrobiota, Probable genus 10, Lachnospiraceae AC2044 group, WCHB1-41, and VadinBE97 were higher in Z39 than in Y9113, while the opposite was observed for Saccharofermentans, UCG-010, and NK4A214 group (p < 0.05). Both principal coordinates analysis (PCoA) and partial least squares discrimination analysis (PLS-DA) revealed clear distinctions in the rumen bacterial communities between Y9113 and Z39. Metabolomic analysis identified eighteen differential metabolites among L268, Z39, and Y9113, with six showing strong correlations with the rumen microbiota. These findings suggest that the feed value of rice straw is influenced by the variety under the same cultivation conditions, due to nutritional disparities that subsequently affect the rumen microbial community and metabolite profiles. This study offers valuable data and insights for the strategic resource utilization of rice straw from different varieties in the livestock industry. [ABSTRACT FROM AUTHOR]

Purpose: The iron reduction in paddy soils, which is mainly driven by iron-reducing bacteria (IRB) communities is vital for iron and other nutrient supplies and contamination management. This study aimed to investigate biochar effects on the community structure of IRB in paddy soils and the iron reduction driven by them in terms of iron reduction dynamic and secondary iron mineral composition. Materials and methods: We isolated bacterial iron reduction in paddy soils in a constructed system with the bacteria source from paddy soils and IRB-selective media, with decoupling the effects of complicated geochemical factors from natural environments. Rice straw biochar was added into the iron-reduction system at 1 and 3% rates (referred to as BC1 and BC3). The putative IRB community was analyzed using 16 S rRNA gene sequencing, the dynamic of Fe(II) were tested by ferrozine test method, and the products from bacterial iron reduction were analyzed by XRD and a sequential extraction procedure. Results and discussion: Biochar at 1 and 3% (BC1 and BC3) rates notably increased the relative abundance of Bacillota phylum of paddy soils by 52.2 and 55.0% in comparison with control, and decreased Pseudomonadota and Thermodesulfobacteriota significantly. Moreover, BC1 and BC3 markedly increased the relative abundance of a typical hydrogen (H2)-producing genus (Clostridium sensu stricto) by 64.8 and 62.2%, respectively. PCA analysis also showed that putative IRB communities in biochar treatments were significantly different from those in the control. Fe(II) concentrations in BC1 (1.92–10.0 mg/L) and BC3 (3.80–12.4 mg/L) were much higher than those in the control (0.27–0.83 mg/L), implying the enhancement of bacterial iron reduction related to the biochar addition. XRD analysis and sequential extraction showed that siderite was the major secondary iron mineral of bacterial iron reduction due to biochar addition, whereas considerable amounts of ferrihydrite, akaganeite, and magnetite were also observed in the control. Conclusion: It suggests that the increase in Bacillota and Clostridium sensu striction in paddy soils owing to biochar addition is responsible for bacterial iron reduction enhancement. The promotion of iron reduction could facilitate the formation of iron plaque in the rice rhizosphere. Moreover, the high Fe(II) content induced by biochar tends toward Fe(II) oversaturation, resulting in the rapid formation of siderite via precipitation pathways; hence, it is beneficial for heavy metal immobilization in paddy soils through co-precipitation with siderite. [ABSTRACT FROM AUTHOR]

The use of metal nanoparticles (NPs) to enhance hydrogen production in dark fermentation (DF) has become a pioneering field of interest. In particular, iron-based nanoparticles (FeNPs) play a pivotal role in enhancing the activity of metalloenzymes and optimizing feedstock utilization, resulting in improved hydrogen production. This study investigated the effect of FeNPs (magnetite) supplementation at three different concentrations of 50, 100, and 200 ppm in a continuous dark fermenter for the production of hydrogen from rice straw acid hydrolysate. The highest hydrogen production rate of 2.6 ± 0.3 NL H2/L-d was achieved with the addition of 100 ppm of nanoparticles, representing a 53% increase compared to the condition without FeNPs addition. This improvement was driven by a microbial community in which Clostridium was the major dominant genus. In addition, increasing the nanoparticle concentration to 100 ppm resulted in an increase in butyrate concentration to 2.0 ± 0.1 g/L, which is 43% higher than the butyrate concentration without FeNPs. However, when the NP concentration was increased to 200 ppm, the hydrogen production rate decreased to 1.6 ± 0.2 NL H2/L-d. This study can serve as a guideline for future research aimed at evaluating the effects of FeNPs in continuous dark fermentation systems. This work highlights the potential benefits and challenges associated with the use of FeNPs, paving the way for future studies to optimize their application and improve the efficiency of dark fermentation processes. [ABSTRACT FROM AUTHOR]

This study explores the blending of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) with rice straw micro-particles (10 to 30 wt%, ≤ 250 μm) to create biocomposites using a kinetic mixer. It examines the effects of chain extender (J) and maleic anhydride (MA) as compatibilizers on material properties. Biocomposites underwent 500 h accelerated weathering to simulate environmental conditions, with analysis via Fourier-transform infrared spectroscopy (FTIR), mechanical testing, dynamic mechanical analyses (DMA), and rheological evaluations. Results indicate that the chain extender's superior performance over MA, generating 6% insoluble content compared to 1% with MA. Scanning electron microscopy (SEM) revealed reduced interfacial voids in biocomposites treated with compatibilizers. The addition of the rice straw was found to increase the tensile modulus from 2.3 to 3.4 indicating a 43% increase after 40 wt% rice particles; all the while reducing the tensile strength and ductility. Post-weathering, Joncryl® treated samples retained properties better than MA-treated ones, showing enhanced crosslinking and less decline in tensile strength (10–19% reduction for J vs. 27–30% for MA). Compatibilizers, especially the chain extender, play a crucial role in strengthening PLA and PBAT biocomposites, particularly under accelerated weathering. [ABSTRACT FROM AUTHOR]

Rice straw is used as livestock feed and compost. Ferimzone and tricyclazole, common fungicides for rice blast control, can be found in high concentrations in rice straw after unmanned aerial vehicle (UAV) spraying, potentially affecting livestock and human health through pesticide residues. In this study, an optimized method for the analysis of the two fungicides in rice straw was developed using the improved QuEChERS method. After the optimization of water and solvent volume, extraction conditions including ethyl acetate (EtOAc), acetonitrile (MeCN), a mixed solvent, and MeCN containing 1% acetic acid were compared. Different salts, including unbuffered sodium chloride, citrate, and acetate buffer salts, were compared for partitioning. Among the preparation methods, the MeCN/EtOAc mixture with unbuffered salts showed the highest recovery rates (88.1–97.9%, RSD ≤ 5.1%). To address the severe matrix effect (%ME) of rice straw, which is characterized by low moisture content and cellulose-based complex matrices, samples were purified using 25 mg each of primary–secondary amine (PSA) and octadecylsilane (C18), without pesticide loss. The developed method was validated with a limit of quantification (LOQ) of 0.005 mg/kg for target pesticides, and recovery rates at levels of 0.01, 0.1, and 2 mg/kg met the permissible range (82.3–98.9%, RSD ≤ 8.3%). The %ME ranged from −17.6% to −0.3%, indicating a negligible effect. This optimized method was subsequently applied to residue studies following multi-rotor spraying. Fungicides from all fields and treatment groups during harvest season did not exceed the maximum residue limits (MRLs) for livestock feed. This confirms that UAV spraying can be safely managed without causing excessive residues. [ABSTRACT FROM AUTHOR]

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Biochar produced from wood residues may provide a new method and material for managing the environment, particularly in terms of carbon sequestration and contaminant remediation. Additionally, biochar produced from wood residues is free of chemical fertilizers, likewise in rice straw, wheat straw, corn straw, etc. This study investigated the removal of iron from aqueous solutions by a novel low-cost and eco-friendly biochar made from hardwood trees and modified by adding MgCl2 for effective phosphate removal. Optimal adsorption conditions were determined through studies of adsorption time, pH, and adsorbent dosage. Batch equilibrium isotherm and kinetic experiments and pre/post-adsorption characterizations using FESEM–EDS, XRD, and FTIR suggested that the presence of carboxyl group elements and colloidal and nano-sized MgO (periclase) particles on the biochar surface were the main adsorption sites for aqueous iron and phosphate respectively. In this study, the HW and MgO-HW biochar showed excellent Dubinin-Radushkevich isotherm (D-R) maximum adsorption capacities of 289.45 and 828.82 mg/g for iron and phosphate. The kinetic study for iron and phosphate adsorption was described well by pseudo second-order model and pseudo second-order model respectively. The HW biochar and the prepared MgO-HW biochar exhibited commendable iron adsorption (98.25%) performance at 10 pH units and phosphate (96.22%) at pH 6 respectively. Thus, this research reveals a waste-to-wealth strategy by converting hardwood waste into mineral-biomass biochar with excellent Fe and P adsorption capabilities and environmental adaptability. [ABSTRACT FROM AUTHOR]

Among the most abundantly available bioresources, lignocellulosic biomass offers a 'green renewable' alternative resource for producing high-value biomaterials suitable for acoustic applications. In this study, a systemic process is developed to fabricate sound absorbing material using refined cellulosic microfibrils generated from natural deep eutectic solvent (NADES) pretreated rice straw. Physico-chemical characterization using FTIR and FESEM analysis confirmed substantial removal of the hemicellulose and lignin from the extracted cellulosic microfibrils. Moreover, the surface area after NADES pretreatment increased to 12.55 m2/g from 2.18 m2/g of raw rice straw, suggesting the enhanced potential of sound dissipation within the biomaterial. The noise reduction coefficient (NRC) of the NADES pretreated rice straw was increased to 0.55 compared to 0.41 with untreated rice straw. Sound absorption performance shows an increasing trend with the increase in sample thickness (25 mm to 50 mm); however, no significant improvement in sound absorption was observed with an air gap of more than 20 mm. Overall, the tested biomaterial shows comparable NRC to commercially available synthetic sound absorbing materials. [ABSTRACT FROM AUTHOR]

Recycling organic waste and water treatment residues in nanoform is a promising technology in various farming systems, and its effect on aggregate stability, biological activity, and canola production in degraded soils is largely unknown. Hence, we evaluated the effect of nano-biochar (nB) and nano-water treatment residues (nWTR) at levels 50, 100, and 250 mg kg−1 as compared to soil without amendments on the aggregate stability, biological activity, and canola yield in degraded soil. The results showed that the structure coefficient (SC) values are higher when nB and nWTR are added at 100 mg kg−1 soil than at levels 50 and 250 mg kg−1. In our study, the high aggregate stability in the soil treated with nB and nWTR is likely due to their higher content of nutrients, organic carbon, clay, and CEC. The seed weight of the canola plant increased with increasing nB by more than 64%, while it decreased with increasing nWTR. Microbial biomass carbon (MBC) and the activity of dehydrogenase (DHA) and catalase (CLA) increased significantly in the treated pots with the addition of nB and nWTR at various rates. The results of the pot experiment recommended that the applications of nWTR and nB could be used as a promising strategy to improve soil quality and crop yield while also increasing the recycled efficiency of WTR and rice straw. [ABSTRACT FROM AUTHOR]

Rice straw is an agricultural by-product that is considered to have the potential to be processed into pulp and various kinds of its derivative products. Pulping condition is an essential prior step to isolate cellulose from fibers. In this study, atmospheric hot soda pulping (AHSP) and soda pulping (SP) methods were successfully used to manufacture pulp and paper from rice straw residues. Pulp modification using water-soluble chitosan was performed aimed at increasing the hydrophobicity of the pulp and paper. X-ray diffraction analysis (XRD) results revealed an increased degree of crystallinity of pulp after both treatments compared to native rice straw. The significant effect of pulping process and chitosan concentration on paper hydrophobicity and its mechanical properties were conducted by performing ANOVA and Duncan tests. According to the statistical results, pulping types, chitosan concentration, and their interaction significantly affected the hydrophobicity but not the mechanical properties of paper (p < 0.05). The best hydrophobicity properties were obtained from AHSP 2% chitosan paper (water absorption of 24.23 ± 1.32% and contact angle (θe) 122.852 ± 0.268) while the best tensile properties of paper were obtained from SP 2% chitosan (tensile strength (S) 1401 N/m). However, the thermal stability was not affected by chitosan concentration. According to the micrographs by Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM–EDS) images, chitosan addition in the paper created changes in surface characteristics compared to the unmodified pulp possibly due to fiber–fiber and fine-fiber flocculation phenomenon Besides, the presence of chitosan can be seen in the N element of the EDS result. [ABSTRACT FROM AUTHOR]

Extensive investigations have been performed on Egyptian rice straw (RS) fibre residues to be employed as a supplementary reinforcement material in polymer composites. In this study, two identical groups based on carbon black (CB) filled styrene butadiene rubber (SBR) vulcanisates were prepared by incorporating different proportions (10–50 phr) of treated and untreated rice straw (TRS/ URS) in the SBR composites to examine their effects on some of the demanded properties in rubber applications. Maleic anhydride (MA), as a coupling agent, was added to improve the interfacial bonding between the hydrophilic RS natural fibre and the hydrophobic SBR matrix. The TRS and URS were selectively grinded through a grinding machine to obtain RS fine powder with a selective grain size distribution ranging from about 20–180 μm. Some important physico-mechanical properties of the rubber vulcanisates were studied. The prepared samples were analysed by using X- ray diffractometer (XRD) and scanning electron microscopy (SEM). The tensile strength (TS), modulus (M100) and hardness values of TRS filled composites were almost superior compared to the URS ones, and 20 phr of TRS was found to be the optimum filling in SBR vulcanisates and this was obviously revealed through all the mechanical properties results as well as in the percentage swelling findings. The SEM analysis indicates that the presence of MA increases the interfacial interaction between SBR, and the alkali treated rice straw fibres, as well it was found to be in complete agreement with the TS findings. The XRD analysis reveals that the alkaline pretreatment of RS fibres was found to yield a higher crystallinity index for the SBR vulcanisates. The results indicate the potential of using TRS as filler in the rubber industry for cost reduction and raising the environmental credentials of the product. [ABSTRACT FROM AUTHOR]

Background: The current practice of weed control in grass planting relies on the use of inorganic materials. This approach has the potential to damage the environment and is an inefficient method for controlling weeds in the cultivation of Super napier grass. This study aims to examine the use of organic mulch as a means of controlling weeds in the cultivation of forage, particularly Super napier grass. Methods: The experiment employed a randomized block design with four treatments and five replications. The treatments were as follows: no mulch (NM) served as the control treatment, rice straw mulch (RSM), rice husk mulch (RHM) and sawdust mulch (SDM). Each of these treatments was plotted with 3.5 m × 2.8 m in size. The experiment was conducted during the summer season, from April to September 2023, in Macorawalie, Panca Rijang, Sidenreng Rappang, South Sulawesi, Indonesia. The observed parameter consisted of fresh weight, dry matter, growth, production and chemical soil. Result: The experimental results revealed that the use of organic mulch resulted in significant effect on soil chemical properties as it was proven to increase the N and C-organic contents of the soil. Sawdust mulch resulted in significant decrease in weed population as compared to other treatments of organic mulch. [ABSTRACT FROM AUTHOR]

The high extractives content in rice straw severely hinders surface adhesion, resulting in poor strength and dimensional stability of rice straw particleboard bonded with castor oil-based polyurethane (CPUR) resin. In this study, rice straw was pretreated with liquid hot water (LHW) at 150 °C for 20 min to reduce its extractives content for particleboard production with CPUR resin. The effects of LHW pretreatment on the chemical composition of the rice straws was evaluated. In addition, effects of CPUR resin dosage and density on mechanical properties and dimensional stability of the rice straw particleboards were investigated. The results indicated that LHW pretreatment significantly reduced the extractives and hemicellulose contents of the rice straw. The LHW pretreatment significantly improved the mechanical properties and dimensional stability of the rice straw particleboards. The overall performances of the rice straw particleboards were enhanced as the CPUR dosage increased. Increase of density led to upgraded mechanical properties but lowered dimensional stability of the rice straw particleboards. [ABSTRACT FROM AUTHOR]

A powerful carbon-based solid acid catalyst and furfural were obtained from rice straw (RS) biomass resource. The acid catalyst was prepared through the carbonization and sulfonation of RS. Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, N2 adsorption-desorption, and ammonia temperatureprogrammed desorption (NH3-TPD) were used to characterize the catalysts. The effect of sulfonation time (4 h to 16 h) on the structure and acidity of the catalysts was elucidated. After 16 h of sulfonation, the BET surface area and the total acidity of the catalyst reached 415 m2/g and 7.48 mmol/g, respectively. Moreover, strong acid sites accounted for more than 63% of acidity. The catalyst was then used for the conversion of RS into furfural in water. The influence of reaction temperature and time while using the catalyst on the conversion process was also investigated. The catalyst exhibited high activity in the conversion of RS, with a furfural yield of 68.3 g/kg RS at 160 °C in 5 h. [ABSTRACT FROM AUTHOR]

Bio-oil produced via fast pyrolysis, irrespective of the biomass source, faces several limitations, such as high water content, significant oxygenated compound concentration (35–40 wt.%), a low heating value (13–20 MJ/kg), and poor miscibility with fossil fuels. These inherent drawbacks hinder the bio-oil's desirable properties and usability, highlighting the necessity for advanced processing techniques to overcome these challenges and improve the bio-oil's overall quality and applicability in energy and industrial sectors. To address the limitations of bio-oil, a magnetic bimetallic oxide catalyst supported on activated rice straw biochar (ZrO2-Fe3O4/AcB), which has not been previously employed for this purpose, was developed and characterized for upgrading rice straw bio-oil in supercritical butanol via esterification. Furthermore, the silica in the biochar, combined with the Lewis acid sites provided by ZrO2 and Fe3O4, offers Brønsted acid sites. This synergistic combination enhances the bio-oil's quality by facilitating esterification, deoxygenation, and mild hydrogenation, thereby reducing oxygen content and increasing carbon and hydrogen levels. The effects of variables, including time, temperature, and catalyst load, were optimized using response surface methodology (RSM). The optimal reaction conditions were determined using a three-factor, one-response, and three-level Box-Behnken design (BBD). The ANOVA results at a 95% confidence level indicate that the results are statistically significant due to a high Fisher's test (F-value = 37.07) and a low probability (p-value = 0.001). The minimal difference between the predicted R² and adjusted R² for the ester yield (0.0092) suggests a better fit. The results confirm that the optimal reaction conditions are a catalyst concentration of 1.8 g, a reaction time of 2 h, and a reaction temperature of 300 °C. Additionally, the catalyst can be easily recycled for four reaction cycles. Moreover, the catalyst demonstrated remarkable reusability, maintaining its activity through four consecutive reaction cycles. Its magnetic properties allow for easy separation from the reaction mixture using an external magnet. [ABSTRACT FROM AUTHOR]

Recently, returning rice straw to soil has become a common problem in wheat production because it causes decreased wheat seedling emergence. Allelopathy is an important factor affecting seed germination. However, the effects of rice straw extracts on wheat seed germination and seedling growth remain unclear. Wheat seeds and seedlings were treated with 30 g L−1 of rice leaf extracts (L1), 60 g L−1 of rice leaf extracts (L2), 30 g L−1 of rice stem extracts (S1), 60 g L−1 of rice stem extracts (S2) and sterile water (CK) to study the allelopathic effects of rice straw extracts on wheat seed germination and seedling growth. The α-amylase and antioxidant enzyme activities in wheat seeds; the agronomic traits, photosynthetic indicators, and nutrient contents of wheat seedlings; and the phenolic acids in rice stem extracts were determined. Common allelochemicals, including 4-hydroxybenzoic acid, hydrocinnamic acid, trans-cinnamic acid, vanillic acid, benzoic acid, protocatechualdehyde, caffeic acid, syringic acid, sinapic acid, and salicylic acid, were detected in rice stem extracts. Low-concentration rice leaf and stem extracts (30 g L−1) had no effect on the germination rate of wheat seeds. High-concentration (60 g L−1) rice stem and leaf extracts decreased the seed germination rate by 11.00% and 12.02%. Rice stem extract (60 g L−1) decreased the α-amylase activity, and gibberellin content of wheat seeds but increased superoxide dismutase, peroxidase, and catalase activities and malondialdehyde content in wheat seeds. Allelochemicals entered the internal tissues of wheat seeds, where they decreased the gibberellin content and α-amylase activity and increased the antioxidant enzyme activity, ultimately leading to an inhibitory effect on seed germination. Rice stem and leaf extracts decreased the SPAD value and photosynthetic indicators of wheat seedlings. Rice stem extract (60 g L−1) decreased the fresh weight and root length of wheat seedlings by 31.37% and 45.46%. Low-concentration rice leaf and stem extract (30 g L−1) had no effect on the nutrient contents of wheat seedlings. Rice leaf and stem extracts (60 g L−1) decreased the nitrogen and potassium contents of wheat seedlings. These results indicated that low-concentration rice leaf and stem extract (30 g L−1) had no effect on wheat seed germination and the high-concentration rice stem extract (60 g L−1) released allelochemicals and inhibited wheat seed germination and seedling growth. These findings provide a basis for the improvement of straw return techniques. [ABSTRACT FROM AUTHOR]

The effects of fallow season water and straw management on methane (CH4) emissions during the fallow season and the subsequent rice-growing season are rarely reported, and the underlying microbial mechanisms remain unclear. A field experiment was conducted with four treatments: (1) fields flooded in both the fallow and rice seasons (FF), (2) fields drained in the fallow season and flooded in the rice season (DF), (3) FF with straw retention (FFS), and (4) DF with straw retention (DFS). The CH4 emissions in fields under different water and straw treatments were monitored using the static closed chamber method. Methanogenic and methanotrophic communities in these fields were examined using terminal restriction fragment length polymorphism (T-RFLP) analysis based on the mcrA gene and pmoA gene encoding methyl coenzyme M reductase and particulate methane monooxygenase, respectively. The results showed that CH4 emissions were significantly affected by water management, straw retention, season, and their interactions. Over 80% of CH4 emissions occurred during the rice season. Field drainage during the fallow season reduced CH4 emissions by 47.0% and 53.8% with and without straw during the rice season, respectively. Water management altered the abundance and composition of methanogens and methanotrophs, whereas the effects of straw retention were less pronounced. The quantitative polymerase chain reaction (qPCR) assay revealed that field drainage in the fallow season decreased the mcrA gene abundance by 30.0% and 23.2% with and without straw in rice season, respectively, and increased the pmoA gene abundance by 108.9% and 213.7% with and without straw in rice season, respectively. CH4 flux was significantly positively associated with mcrA gene copy number and the ratio of mcrA to pmoA gene copy number, whereas it was significantly negatively correlated with the pmoA gene copy number. Results indicated that fallow drainage greatly decreased CH4 emission not only during the fallow season but also during the subsequent rice season by altering the community composition of methanogens and methanotrophs. These findings provide scientific insight into the role of water and straw management in controlling CH4 emissions through microbial community dynamics. [ABSTRACT FROM AUTHOR]

In this study, two green extraction methods are explored to valorize rice straw into cellulose fibers (CFs), namely subcritical water extraction (SWE) and combined ultrasound‐heating treatment (USHT). The resultant fibers are, thereafter, successfully pretreated with (3‐glycidyloxypropyl) trimethoxysilane (GPS) and incorporated at 3% wt into poly(butylene succinate) (PBS) by melt‐mixing. The green composites are shaped into films by thermo‐compression and characterized in terms of their performance for food packaging applications. The chemical analysis of the fibers reveals that SWE is more effective to selectively remove hemicelluloses than USHT, whereas silanization promotes the removal of lignin in both fiber types. Fiber incorporation, more notably in the case of the silanized fibers, restricts the movement of the PBS chains, indicating good interaction with the biopolyester matrix. In particular, CFs act as antinucleating agents in PBS, delaying both glass transition and crystallization from the melt phenomena and hindering crystal formation. Furthermore, the fibers mechanically reinforce and improve the oxygen barrier of the PBS films. The highest barrier enhancement is obtained for the thermo‐compressed composite film with silanized fibers obtained by SWE, yielding a decrease of nearly 20% in the permeability to oxygen versus the unfilled PBS film. [ABSTRACT FROM AUTHOR]

The removal of caesium radionuclides from an aqueous solution by flotation using rice straw (RS) agricultural waste as a low-cost and eco-friendly adsorbent in the presence of potassium ferrocyanide (KFC) was investigated. The influence of many adsorption parameters and flotation was evaluated on the removal efficiency of 137Cs. The adsorption results demonstrated that the concerned radionuclide was efficiently removed in the presence of 2 × 10−4 mol/L KFC using 10 g/L RS at pH ≥ 7. The double exponential kinetic model and the Freundlich model were the best models for fitting the adsorption kinetic and isotherm data, respectively. The maximum adsorption capacity of RS, calculated from the Langmuir model, was 280.405 mg/g. after being transferred to the flotation cell, 137Cs loaded onto ferrocyanide-modified rice straw (FMRS) was successfully floated at pH 7 using 3 × 10−4 mol/L cetyltrimethylammonium bromide (CTAB) surfactant in the presence of 4% ethanol. Removal percentages of 56% and > 99.5% were achieved for 137Cs-loaded FMRS within 5 min using sodium dodecyl sulphate (SDS) and CTAB, respectively. The results obtained in this investigation indicate the efficiency of the suggested strategy and hence its applicability for the removal of 137Cs+ from radioactive liquid wastes. [ABSTRACT FROM AUTHOR]

Objective: This study investigated the impact of Aspergillus niger lysing polysaccharide monooxygenase (AnLPMO) on in vitro rumen microbial fermentation of rice straw. Methods: AnLPMO was heterologously expressed in Escherichia coli. Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy analyzed the surface structure of rice straw after AnLPMO treatment. Two in vitro experiments, coupled with 16S highthroughput sequencing and quantitative real–time polymerase chain reaction techniques, assessed the influence of AnLPMO on rumen microbial fermentation of rice straw. Results: AnLPMO exhibited peak activity at 40°C and pH 6.5, with a preference for rice straw xylan hydrolysis, followed by Avicel. AnLPMO application led to the fractional removal of cellulose and hemicelluloses and a notable reduction in the levels of carbon elements and C–C groups present on the surface of rice straw. Compared to the control (no AnLPMO), supplementing AnLPMO at 1.1 to 2.0 U significantly enhanced in vitro digestibility of dry matter (IVDMD, p<0.01), total gas production (p<0.01), and concentrations of total volatile fatty acids (VFA, p<0.01), acetate (p<0.01), and ammonia-N (p<0.01). Particularly, the 1.4 U AnLPMO group showed a 14.8% increase in IVDMD. In the second experiment, compared to deactivated AnLPMO (1.4 U), supplementing bioactive AnLPMO at 1.4 U increased IVDMD (p = 0.01), total gas production (p = 0.04), and concentrations of total VFA (p<0.01), propionate (p<0.01), and ammonia-N (p<0.01), with a limited 9.6% increase in IVDMD. Supplementing AnLPMO stimulated the growth of ruminal bacterial taxa facilitating fiber degradation, including Proteobacteria, Spirochaetes, Succinivibrio, Rikenellaceae_RC9_ Gut_Group, Prevotelaceae_UCG-003, Desulfovibrio, Fibrobacter succinogenes, Ruminococcus albus, R. flavefaciens, Prevotella bryantii, P. ruminicola, and Treponema bryantii. Conclusion: These findings highlight AnLPMO's potential as a feed additive for improving rice straw utilization in ruminant production. [ABSTRACT FROM AUTHOR]

Objective: This experiment aimed to evaluate the effects of replacing concentrates with cassava root-top silage (CARTOS) on feed intake, digestibility, rumen fermentation, blood parameters, and growth performance of beef cattle. Methods: Twenty crossbred bulls with a body weight (BW) of 226±56 kg were randomly assigned to one of five treatments for 90 d in a randomized complete block design having four blocks based on BW. The concentrates were replaced by CARTOS at levels of 0%, 25%, 50%, 75%, and 100% dry matter (DM). Animals were fed dietary treatments at 1.8% BW, with rice straw offered ad libitum. Results: The DM and crude protein (CP) intake were decreased (p<0.01, p = 0.04) when the diet’s CARTOS level was increased. The digestibility of DM, OM, and CP were not different among treatments, while fiber digestibility was increased with the inclusion of CARTOS (p = 0.03). The addition of CARTOS to replace concentrates did not change ruminal pH or volatile fatty acid proportions except for acetic acid, which increased with the addition of CARTOS (p = 0.03). The ruminal ammonia-nitrogen (NH3-N) was decreased (p<0.01) with increasing levels of CARTOS. The blood glucose and blood urea nitrogen decreased (p = 0.01) with the addition of CARTOS at 100%, whereas total protein and hematological parameters did not change with increasing levels of CARTOS. The use of CARTOS to substitute concentrates at 75% and 100% decreased average daily gain (ADG) and gain to feed ratio (G:F) (p<0.01); therefore, the addition of CARTOS up to 50% maintained ADG and G:F in beef cattle. Conclusion: CARTOS can replace concentrates up to 50% in beef cattle diets without adversely affecting feed intake, nutrient digestibility, rumen fermentation characteristics, blood parameters, or growth performance of beef cattle. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The current study pertains performance optimization of multiple responses of a variable compression ratio diesel engine in regard to variation in load, compression ratio, and fuel type. A total of 9 number of experimental runs are performed as per the design of experiment suggested by Taguchi technique for three different load of 4 kg, 8 kg, and 12 kg, compression ratio of 14, 16, and 18, and fuel type of diesel, e-diesel (85% diesel and 15% bioethanol blend), and nano-fuel (85% diesel and 15% bioethanol blend with 25 ppm alumina nanoparticles). The bioethanol used in this study prepared from waste rice straw. The energy efficiency (η), exergy efficiency (ɛE), nitrogen oxide emission, and % relative cost variation are measured as output performances of this study. Fuel type has been identified as the most promising factor to energy efficiency, and exergy efficiency with a contribution of 41.1% and 64.53%, respectively. Load has been identified as the most promising factor to NOx emission, and % relative cost variation with a contribution of 71.69% and 34.92%, respectively. The compression ratio has been identified as the least contributing factor for all output performances. Nano-fuel attains higher sustainability index of 1.923 compared to other fuel due to lower depletion rate. Multiple output performance optimization has been carried out for maximum η, and ɛE, as well as minimum nitrogen oxide emission, and % relative cost using Taguchi–Grey technique. 19.37% enhancement in overall performance of the test engine is observed for determined optimal input parameters of 4 kg load, 18 compression ratio and nano-fuel. [ABSTRACT FROM AUTHOR]

The primary objective of the present study was to transform discarded agricultural remnants and poultry waste into value-added materials. Rice straw and chicken feathers are disposed of after their primary consumption into landfills or are incinerated, causing pollution and environmental threats. In this study, epoxy composites were fabricated using different volume proportions (5–45%) of these raw and alkali-treated remnants, and their mechanical strength was tested. The flexural strength of the rice straw composites and chicken feather composites initially decreased with the addition of fibers from 5 to 35 vol% and then the values increased when the fiber content was more than 35 vol%. The chicken feather composites showed increased impact strength with fiber addition. Alkali treatment of the rice straw resulted in improved flexural and impact strengths of the composites due to the removal of the waxy layer on the fiber surface, which was observed in the FTIR studies. Alkali treatment of the chicken feathers did not produce any significant change in the flexural strength of the composites, but their impact strength increased with fiber addition. Hybrid composites fabricated using rice straw and chicken feathers exhibited enhanced flexural and impact strength properties both with and without the alkali treatment, corroborating the synergistic effect of these fibers. SEM analysis of the fractured samples showed noteworthy interfacial adhesion between the fibers and matrix. This study presents a better method for converting these disposable materials into value-added usable materials and increasing their life cycle in the circular economy. [ABSTRACT FROM AUTHOR]

There have recently been several initiatives to develop eco-sustainable materials because of the growing concern over ecological contamination caused by the overuse of synthetic materials. Previous studies in literature have explored the development of rice straw waste-based epoxy composites. Another waste hazard of concern in the current times is that of waste tire rubber. The present study investigates the physico-mechanical properties of a unique hybrid composite consisting of recycled waste tire rubber and rice straw reinforced composite, which has not been investigated in the literature. Their density, water absorption, hardness, tensile and flexural strengths were examined with variations in the proportion of rubber particles and rice husk. Increase in the rubber content resulted in proportional rise in the water uptake, hardness, tensile strength, and flexural strength. The composite with 25 wt.% of rubber and 5 wt.% of rubber showed the highest tensile strength and strain of 12.5 MPa and 0.015, respectively. The composite with 15% RS and WTR showed a 14.26% increase in flexural strength, with the neat composite exhibiting the highest strength. The composite material can be used as structural panels for instruments or devices in low load bearing applications. The developed sustainable material with waste generated from used tires and rice husk can aid in decreasing the harmful effects caused on the environment and human health during their disposal. [ABSTRACT FROM AUTHOR]

Cellulosic fiber from rice straw provides a sustainable alternative to the environmental menace of the field burning problem. Response surface methodology and artificial neural network were applied in the organosolv pulping process to evaluate the responses of total pulp yield (TPY, %), holocellulose content (HC, %), and Klason lignin (KL, %). The optimum input parameters for these reactions were solvent ratio (formic acid: acetone 8:2), chemical doses (68%), time (269 min), and temperature (106 °C) with a response value of TPY (49.8%), HC (80.35%) and KL (3.85%). Artificial neural networks showed better-optimized results as compared to the response surface methodology. An exceptional fiber separation was observed using SEM analysis, while FT-IR analysis confirmed the significant removal of lignin as per drastic reduction in the absorption band at around 1505 cm−1. The cellulose maximization and lignin reduction in the optimized pulp were also confirmed using EDX, XRD, and TGA analysis. Further, the effects of the addition of cationic starch, carboxymethyl cellulose, and xanthan gum were studied for making fiber composite hand sheets. The surface properties were optimum at the bio-additive doses of 3% (oven-dried) in both cases. However, the strength properties reached the maximum with the addition of 2% bio-additives. Nevertheless, cationic starch showed more suitable bio-additive for hand sheet packaging papers with better surface and strength properties. This study determined the optimum organosolv process parameters at the lab scale and further confirmed the suitability of the developed material for packaging applications with improved strength, surface, and optical properties. [ABSTRACT FROM AUTHOR]

Purpose: Incorporating rice straw into upland has been adopted as a strategy to increase crop productivity and decrease poisoning to rice from reducing substances accumulation as well as mitigate methane emission from paddy fields in South China. However, the mechanism underlying long-term ex situ incorporation of rice straw in upland on soil organic carbon (SOC) and crop yields through microbial metabolism remains unclear. Materials and methods: Hence, a field experiment was established to investigate the response mechanism of SOC and crop yields underlying microbe-mediated carbon dynamics with nutrient stoichiometry by ex situ incorporation of rice straw in upland. Results and discussion: The results showed that the treatment of cropping with chemical fertilizers plus rice straw (SCF) had the highest SOC accumulation rate (0.14 ± 0.03 g C kg−1 yr−1) during the 22-year experimental period. The mean yields of rapeseed and sweet potato were increased by 5.0% and 4.7% in the SCF treatment, correspondingly, compared with the treatment of cropping with chemical fertilizers (CF). Additionally, based on ecoenzymatic stoichiometry, soil microorganisms were found to be co-limited by carbon and phosphorus, which was aggravated by the decrease of soil available nutrients. The SCF treatment exhibited a higher soil microbiomass, resulting in an increased secretion of ecoenzymatic activities to mediate stoichiometric imbalance and mitigate nutrient competition between plant and microbial nutrient limitations. The findings revealed a significant association between stoichiometric imbalance and both SOC and crop yields, respectively. Conclusions: Therefore, our study indicated that long-term ex situ incorporation of rice straw in upland could be adopted as an effective agricultural management strategy to improve SOC and crop yields. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present study, nano-ligninwas synthesized from rice straw using Lactobacillus rhamnosus for the cost-effective removal of harmful dye from wastewater. The UV absorption maxima of the synthesized nano-lignin were around 280–290 nm. Several FTIR bands between 1075 cm−1 to 3500 cm−1 confirmed the successful confirmation of nano-lignin synthesis from rice straw. STEM and DLS studies confirmed the spherical morphology of nano-lignin with an average particle size of 286.3 nm. The nano-lignin showed a negative zeta potential value of −16.9 ± 5.94 mv. Afterward, nano-lignin was used to remove basic methylene blue (MB), phenol red (PR),and brilliant green (BG) dye from aqueous solutions. The adsorption of these dyes increased with increased incubation time. The adsorption concentration of the MB, PR, and BG dyes ranged from 3.5 mg/g to a final of 24 mg/g, 2.5 mg/g to 42.5 mg/g, and 1.5 gm/g to 5.5 mg/g, respectively.

• Rice straw-derived dissolved organic matter (DOM) included four main components. • The presence of goethite significantly promotes the straw decomposition process. • OM's adsorption capacity for Cd increased with the straw decomposition time. • The presence of minerals promoted the OM's adsorption capacity and affinity of Cd. • Surface precipitation and complexation dominant Cd adsorption by OM. Organic matter (OM) derived from the decomposition of crop residues plays a key role as a sorbent for cadmium (Cd) immobilization. Few studies have explored the straw decomposition processes with the presence of minerals, and the effect of newly generated organo-mineral complexes on heavy metal adsorption. In this study, we investigated the variations in structure and composition during the rice straw decomposition with or without minerals (goethite and kaolinite), as well as the adsorption behavior and mechanisms by which straw decomposition affects Cd immobilization. The degree of humification of extracted straw organic matter was assessed using excitation-emission matrix (EEM) fluorescence and Ultraviolet-visible spectroscopy (UV-vis), while employing FTIR spectroscopy and XPS to characterize the adsorption mechanisms. The spectra analysis revealed the enrichment of highly aromatic and hydrophobic components, indicating that the degree of straw decomposition and humification were further intensified during incubation. Additionally, the existence of goethite (SG) accelerated the humification of OM. Sorption experiments revealed that the straw humification increased Cd adsorption capacity. Notably, SG exhibited significantly higher adsorption performance compared to the organic matter without minerals (RS) and the existence of kaolinite (SK). Further analysis using FT-IR spectroscopy and XPS verified that the primary mechanisms involved in Cd immobilization were complexion with —OH and —COOH, as well as the formation of Cd-π binds with aromatic C=C on the surface of solid OMs. These findings will facilitate understanding the interactions of the rice straw decomposing with soil minerals and its remediation effect on Cd-contaminated farmland. [Display omitted] [ABSTRACT FROM AUTHOR]

Second-generation bioethanol has garnered considerable interest among researchers due to its utilization of lignocellulosic biomass, such as rice straw, which is both cost-effective and readily available. Nonetheless, the economic viability of large-scale production of second-generation bioethanol remains a significant challenge. There is an urgent need for cost efficiency across three critical stages: pretreatment, hydrolysis, and fermentation. This paper reviews recent advancements in bioethanol production from rice straw and proposes a novel approach to enhance economic feasibility. The inherent recalcitrance of rice straw necessitates the implementation of an appropriate pretreatment method, as this step is crucial for the success of the hydrolysis process. While chemical pretreatment is frequently employed, it often results in increased waste generation and maintenance costs, thereby elevating the overall production expenses. Optimizing reactor configurations for enzyme production, hydrolysis, and fermentation can lead to substantial reductions in production costs. Although enzymatic hydrolysis utilizing commercial enzymes is the predominant method, on-site enzyme production has demonstrated significant cost advantages. Consolidated bioprocessing (CBP) integrates enzyme production, hydrolysis, and fermentation within a single reactor using a single strain or microbial consortium. However, the productivity of bioethanol production from rice straw via CBP is currently low. The proposed novel CBP aims to address the limitations of the original CBP by integrating pretreatment, enzyme production, hydrolysis, and fermentation in a single reactor with a microbial consortium. This innovative approach is expected to minimize contamination risks and reduce equipment installation costs, thereby improving cost-effectiveness. Nevertheless, the implementation of the novel CBP presents challenges, including the establishment of a stable and efficient microbial consortium and the determination of optimal process parameters. Addressing these challenges is essential for the successful application of the novel CBP at an industrial scale. [ABSTRACT FROM AUTHOR]

[Display omitted] • Decomposition decreased Cr(VI) removal by straws regardless of straw types. • Mechanisms of Cr(VI) removal decrease were different for the two straws. • Cr(VI) could be removed by straws via interfacial and solution reactions. • Straw-derived DOM contributed to 12.0%–35.8% of total Cr(VI) removal. Mobility and bioavailability of hexavalent chromium (Cr(VI)) in agricultural soils are affected by interactions between Cr(VI) and returned crop straws. However, the effect of straw decomposition on Cr(VI) removal and underlying mechanisms remain unclear. In this study, Cr(VI) removal by pristine and decomposed rice/rape straws was investigated by batch experiments and a series of spectroscopies. The results showed that straw decomposition inhibited Cr(VI) removal, regardless of straw types. However, the potential mechanisms of the inhibition were distinct for the two straws. For the rice straw, a lower zeta potential after decomposition suppressed Cr(VI) sorption and subsequent reduction. In addition, less Cr(VI) was reduced by the decomposed rice straw-derived dissolved organic matter (DOM) than the pristine one. In contrast, for the rape straw, due to the increased zeta potential after decomposition, the decreased Cr(VI) removal was mainly ascribed to less Cr(VI) reduction by the rape straw-derived DOM. These results emphasized the significant roles of straw surface potential and DOM in Cr(VI) removal, depending on straw types and decomposition, which facilitate the fundamental understanding of Cr(VI) removal by straws and are helpful for predicting the environmental risk of Cr and rational straw return in Cr(VI)-contaminated fields. [ABSTRACT FROM AUTHOR]

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Background and Aim: Rice straw, a widely available agricultural byproduct globally, has significant potential as a basal diet for livestock. The major challenge lies in obtaining high-protein foliage that can be easily extracted using natural water rather than chemical solvents. This study aimed to assess the ability of distilled water to extract protein concentrate from Indigofera leaves (Indigofera zollingeriana Miq.) and to evaluate its effectiveness in enhancing rumen feed fermentation and digestibility in low-quality rice straw basal diets. Materials and Methods: The study was conducted in two experimental series. Experiment 1 was designed to explore the ability of distilled water to extract protein concentrate from fresh and dry Indigofera leaves by comparing it with the 0.1 N NaOH standard solvent. Experiment 2 focused on the in vitro digestibility of protein concentrates extracted from fresh Indigofera leaves based on optimal findings from experiment 1. Five treatments consisting of 0.5% and 1.0% protein concentrate and two extractants (distilled water and 0.1 N NaOH) were used to extract protein from Indigofera leaves. These extracts were then added to rice straw-based diets. Rice straw without supplements was used as a control. The treatments were arranged using a randomized complete design with five replicates. Results: The results of experiment 1 showed that distilled water was superior to 0.1 N NaOH for extracting protein concentrate from fresh Indigofera leaves, as revealed by higher dry matter, protein yield, total amino acids (AA), and total essential AA (EAA) production. For in vitro experiment 2, supplementation with distilled water-extracted protein concentrates successfully increased rumen fermentation and digestibility in rice straw basal diets, as indicated by higher gas production, total volatile fatty acid, and microbial protein levels compared with 0.1 N NaOH. Conclusion: Findings from this study confirm that Indigofera leaf protein concentrate offers a new alternative for enhancing rumen feed fermentation and the digestibility of low-quality rice straw diets. This study implies that it is an easy, cost-effective, and environmentally friendly approach, particularly beneficial for smallholders, to extract protein concentrate from fresh Indigofera leaves using distilled water and use it to enhance the quality of rice straw for ruminant feed. The limitation of this study is that the Indigofera supplement was established using in vitro digestibility under controlled laboratory conditions, which does not reflect real rumen conditions. Therefore, further studies using in vivo digestibility in ruminant animals are required to confirm the ability of the protein extracted from indigofera to enhance rumen feed fermentation in low-protein basal diets.