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Polyhydroxyalkanoates (PHAs) are biodegradable polymers that can be produced from lignocellulosic biomass by microorganisms. Cheap and readily available raw material, such as corn stover waste, has the potential to lessen the cost of PHA synthesis. In this research study, corn stover is pretreated with NaOH under conditions optimized for high cellulose and low lignin with central composite design (CCD) followed by characterization using Fourier-transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Design expert software performed further optimization of alkali pretreated corn stover for high total reducing sugar (TRS) enhancement using CCD using response surface methodology (RSM). The optimized condition by RSM produced a TRS yield of 707.19 mg/g. Fermentation using corn stover hydrolysate by Pseudomonas putida MTCC 2475 gave mcl-PHA detected through g as c hromatography - t andem m ass s pectrometry (GC-MS/MS) and characterization of the PHA film by differential scanning calorimetry (DSC), FTIR, and nuclear magnetic resonance (NMR). Thus, this research paper focuses on using agriculture (stubble) waste as an alternative feedstock for PHA production., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Kukreti, Kumar and Kataria.)

The production of reducing sugar is the most crucial process in the production of cellulosic ethanol and can be divided into two steps. First, pretreatment removes the unwanted constituents of lignocellulose to produce cellulose; then the cellulose is hydrolyzed to glucose (a reducing sugar) in the hydrolysis step. In this work, microwave heating was applied for both alkali pretreatment and sequential acid hydrolysis of corncob in which the conditions were optimized by response surface methodology. The optimal cellulose content in the pretreated corncob was 52.9 % w/w obtained with 1 M sodium hydroxide using a 1:12 weight ratio of corncob to solution at 900 W microwave power for 20 min, which was used to optimize the glucose yield in the following step. The highest yield of 14.8% glucose was achieved with 1.3% w/w sulfuric acid solution at 900 W for 16 min.

Economical bioprocessing of lignocellulosic biomass essentially demands production of fermentable sugars in the concentrated form before their valorization. The present study aimed towards hydrolysis of alkali pretreated sugarcane bagasse at high solid loading and its successive valorization to L (+) lactic acid (LA). Two strategies were evaluated, wherein pretreatment, 12.5% substrate loading, Cellic CTec2 enzyme complex and thermophilic Bacillus coagulans NCIM 5648 were common to the processes. In Process A, when Cellic CTec2 was dosed at 30 FPU g−1 dry biomass, it hydrolyzed 75.8 ± 1.7% cellulose and 88.6 ± 2.1% xylan in 24 h. However, when its loading was changed to 25 mg protein g−1 glucan in Process B, Cellic CTec2 hydrolyzed 72.3 ± 0.3% and 68 ± 0.8% cellulose and xylan respectively. Valorization of glucose-rich filtrates obtained from Process A and B using two different media resulted in 50.4 ± 1.2 g L−1 and 51.24 ± 1.31 g L−1 of LA production from 54.7 to 62.7 g L−1 of glucose respectively. Attaining 1.75–2.4 g L−1 h−1 LA productivity with two scenarios of separate hydrolysis and fermentation is highly encouraging. It opens newer avenues for bio-based LA production using a greener approach. • Batch hydrolysis of high-solids alkali pretreated sugarcane bagasse conducted. • Alternative strategies for separate hydrolysis and fermentation (SHF) evaluated. • ∼70% glucan hydrolysis achieved when Cellic CTec2 dosed on FPU or protein basis. • Released glucose valorized to ∼52.5 ± 2.7 g L−1 lactic acid with B. coagulans. • Short span of 45–54h was the most rewarding feature of SHF carried independently. [ABSTRACT FROM AUTHOR]

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In this work, structural changes and inhibitory effects of lignin from the outer and inner layers of bamboo after alkali pretreatment were investigated. The results revealed that the carbohydrates contents in lignin samples from bamboo outer and inner layers decreased from 22.2% and 21.4 to 10.1% and 10.4% by alkali pretreatment, respectively. Alkali pretreatment could increase the molecular polydispersity index and syringyl/guaiacyl ratio of lignin, decrease lignin molecular weights and cleave the esterified p-coumarate in bamboo lignin. Inhibitory effect of bamboo lignin on cellulose hydrolysis decreased after alkali pretreatment, which could be explained by the lower adsorption capacity of lignin toward cellulases after alkali pretreatment. These findings discovered the structure of alkali pretreated bamboo lignin and enhanced the understanding of the mechanism of alkali pretreatment in increasing enzymatic hydrolysis of bamboo. [ABSTRACT FROM AUTHOR]

Summary: In this study, alkali pretreated corn stover was added as a sacrificial agent to the suspension of Pt/TiO2 to significantly enhanced photocatalytic hydrogen evolution. The changes in structural characteristics of corn stover before and after alkali treatment and photocatalytic reactions were studied. According to the results, the removal of lignin and hemicellulose, as well as the changes in surface morphology, structural components, and functional groups of alkali pretreated corn stover may affect the photocatalytic hydrogen production process. Next, the effects of NaOH concentration, pretreatment time and temperature on hydrogen production were also investigated. Among them, within the scope of the experimental conditions, the optimal hydrogen production is 25.84 μmol h−1. Moreover, the enhancement of photocatalytic hydrogen production is also achieved by using the waste liquid of alkali pretreated. The output of this study may provide a reference for the reuse of alkali‐treated biomass residues and waste liquor in some industries, and make more comprehensive, efficient and green use of native lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

• Valorization of macroalgal residues by anaerobic digestion. • Knife milling and alkaline pretreatment enhanced methane production. • In semi-continuous reactors, alkaline pretreatment enhanced methane by 20%. • Digestates did not exhibit phytotoxicity. • Digestate from codigestion with sludge led to the highest tomato plant growth. The aim of this paper is to investigate the impact of pretreating macroalgal residue (MAR) from agar-agar extraction and its co-digestion with sewage sludge on methane production and the agronomic quality of the digestates produced. First, different pretreatments were assessed on BMP tests. Among milling technologies used, knife milling with a 4 mm-screen improved methane production by 25%. The MAR was then knife milled before alkaline, acid and thermal pretreatment. KOH pretreatment (5% TS basis, 25 °C for 2 days) led to the highest methane improvement. It was applied to semi-continuous anaerobic digestion and methane production achieved 237 Nml/gVS which was 20% higher than the control (198 Nml/gVS). In comparison to MAR mono-digestion, co-digestion with thickened activated sludge produced less methane (184 Nml/gVS) but reduced H 2 S emission by 91%. None of the digestates was toxic for the germination or growth of wheat and tomato plants. Particularly, co-digestion had the highest impact on tomato plant dry weight (+94% compared to soil alone) mainly due to the phosphorous brought by sludge. However, the impact of alkaline pretreatment on plant growth was not significant. [ABSTRACT FROM AUTHOR]

Anaerobic digestion is one of the most prospective and economical techniques to recover energy and simultaneously treat organic fraction of municipal solid waste (OFMSW). However, more often than not, the complex polymeric structure of lignocellulosic fraction and high lipid content of Indian OFMSW prove to be hindrances in realizing the full potential of energy recovery through anaerobic digestion. Pretreatment of OFMSW is an effective method to enhance the efficiency of anaerobic digestion. This paper explores the effect of alkali pretreatment on change in characteristics of OFMSW in India and its subsequent impact on biogas generation. Pretreatment was carried out using 5 M sodium hydroxide (NaOH) solution and varying the initial pH of OFMSW in the range of 8–13 for 24 h. Thereafter, batch anaerobic digestion assays of untreated and pretreated OFMSW were carried out using cow excrement as inoculum. Results indicate that NaOH pretreatment was advantageous in solubilizing the organic matter of OFMSW, thus increasing biogas yield and reduced digestion time. The cumulative biogas generation increased by 19.6–34.8% post-NaOH pretreatment. OFMSW pretreated with NaOH at pH 10 had maximum biogas yield of 407.1 mL/gVS with 68.9% methane content, as compared to 301.9 mL/gVS and 50.3% of untreated OFMSW. A preliminary cost assessment indicated a positive net profit for pretreatment of OFMSW with NaOH at pH ranges of 8–10. [ABSTRACT FROM AUTHOR]

The present work utilized a by-product of the starch industry in Malaysia, Sago bark waste (SB), for pretreatment and enzymatic hydrolysis. SB was subjected to two types of alkaline pretreatment to assess their effect on SB characteristic, inhibitor formation, and enzymatic hydrolysis sugar yield. Dilute sodium hydroxide (DSH) and dilute sodium bicarbonate (DSB) were used for SB pretreatment. The pretreatment was carried out in a conventional heating environment (120ºC) for 10 min before the enzymatic hydrolysis step. The results showed that the treated SB by DSB resulted in higher removal of lignin (28%) compared to DSH (25%). The TGA, XRD, and SEM analysis results revealed that both types of pretreatment have slight differences. The crystallinity index (CI) for DSH and DSB was 43.2% and 41.2%, respectively. Meanwhile, HPLC results illustrated that the only inhibitor present in the pretreatment liquor is acetic acid at 0.25 mg/ml for DBS pretreatment and 0.063 mg/ml for DSH pretreatment. 229 ± 12 mg/g of total reducing sugar was found using DSH pretreatment, which is slightly higher than that one was obtained by DSB pretreatment (219 ± 16 mg/g) after enzymatic hydrolysis step. A similar observation was found on glucose and xylose yield. These results make us interfere that the diluted level of sodium bicarbonate can lead to approximately similar results of sodium hydroxide, which offer a cheap route of the pretreatment process. [ABSTRACT FROM AUTHOR]

The lignocellulosic substrate bioconversion to produce fuel is very potential to be developed in the future. Converting cellulose to simple sugars requires a suitable and inexpensive preliminary treatment. This study aimed to investigate the use of alkali materials as chemicals suitable to delignify corn straw powder. The research was conducted to choose the chemical type for delignification, namely: NaOH, Ca(OH)2, NH3 (NH4OH), and Hydrazine. In the next step, the concentration of the delignification solution for corn straw powder was determined at material/chemical ratio of 1:10 (w/v) and soaked for 8 h at room temperature. The tested alkaline solution concentrations were varied from 0, 2, 4, 6, to 8% (w/v). The pre- and post pretreatments affected the yield of α-cellulose, relative degree crystallinity by an X-Ray Diffraction (XRD), functional groups using a Fourier Transform Infra-Red (FT-IR) and surface morphology using a Scanning Electron Microscopy (SEM). Corn straw substrate in the best treatment will applied in the production of cellulase enzymes. The results showed that NaOH is the best used as a delignifying agent with the highest level of cellulose and the lowest lignin, namely 61.45% and 1.09%, respectively. The NaOH solution at the concentration of 4% gives optimal results, with cellulose content 65.46%, hemicellulose 14.58%, and lignin 8.66%. Based on FTIR, XRD and SEM analysis showed that alkali pretreatment especially with NaOH solution gives the result in which the corn straw cellulose structure becomes swelling. [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.)

Background: As a renewable carbon source, biomass energy not only helps in resolving the management problems of lignocellulosic wastes, but also helps to alleviate the global climate change by controlling environmental pollution raised by their generation on a large scale. However, the bottleneck problem of extensive production of biofuels lies in the filamentous crystal structure of cellulose and the embedded connection with lignin in biomass that leads to poor accessibility, weak degradation and digestion by microorganisms. Some pretreatment methods have shown significant improvement of methane yield and production rate, but the promotion mechanism has not been thoroughly studied. Revealing the temporal and spatial effects of pretreatment on lignocellulose will greatly help deepen our understanding of the optimization mechanism of pretreatment, and promote efficient utilization of lignocellulosic biomass. Here, we propose an approach for qualitative, quantitative, and location analysis of subcellular lignocellulosic changes induced by alkali treatment based on label-free Raman microspectroscopy combined with chemometrics. Results: Firstly, the variations of rice straw induced by alkali treatment were characterized by the Raman spectra, and the Raman fingerprint characteristics for classification of rice straw were captured. Then, a label-free Raman chemical imaging strategy was executed to obtain subcellular distribution of the lignocellulose, in the strategy a serious interference of plant tissues' fluorescence background was effectively removed. Finally, the effects of alkali pretreatment on the subcellular spatial distribution of lignocellulose in different types of cells were discovered. Conclusions: The results demonstrated the mechanism of alkali treatment that promotes methane production in rice straw through anaerobic digestion by means of a systemic study of the evidence from the macroscopic measurement and Raman microscopic quantitative and localization two-angle views. Raman chemical imaging combined with chemometrics could nondestructively realize qualitative, quantitative, and location analysis of the lignocellulose of rice straw at a subcellular level in a label-free way, which was beneficial to optimize pretreatment for the improvement of biomass conversion efficiency and promote extensive utilization of biofuel. [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.)

Crop straws provide enormous biomass residues applicable for biofuel production and trace metal phytoremediation. However, as lignocellulose recalcitrance determines a costly process with potential secondary waste liberation, genetic modification of plant cell walls is deemed as a promising solution. Although pectin methylation plays an important role for plant cell wall construction and integrity, little is known about its regulation roles on lignocellulose hydrolysis and trace metal elimination. In this study, we initially performed a typical CRISPR/Cas9 gene-editing for site mutations of OsPME31 , OsPME34 and OsPME79 in rice, and then determined significantly upgraded pectin methylation degrees in the young seedlings of three distinct site-mutants compared to their wild type. We then examined distinctively improved lignocellulose recalcitrance in three mutants including reduced cellulose levels, crystallinity and polymerization or raised hemicellulose deposition and cellulose accessibility, which led to specifically enlarged biomass porosity either for consistently enhanced biomass enzymatic saccharification under mild alkali pretreatments or for cadmium (Cd) accumulation up to 2.4-fold. Therefore, this study proposed a novel model to elucidate how pectin methylation could play a unique enhancement role for both lignocellulose enzymatic hydrolysis and Cd phytoremediation, providing insights into precise pectin modification for effective biomass utilization and efficient trace metal exclusion. • A CRISPR/Cas9 editing is performed for site mutations of three OsPMEs genes. • Significantly upgraded pectin methylation occurs in three distinct site-mutants. • Higher biomass hydrolyses of mutants are achieved under mild alkali pretreatments. • Cd phytoremediation is achieved by enhancing biomass porosity and accessibility. • A novel mechanism model is proposed for specific dual roles of pectin methylation. [ABSTRACT FROM AUTHOR]

The development and application of high-adsorptive calcined diatomite (C-D) can provide a cost-effective solution for the filter aid industry, which remains a challenge in this field. Herein, an alkali (NaOH) pretreatment was introduced before the calcium oxide (CaO)-mediated hydrothermal activation of C-D. The adsorption performance of the alkali-modified samples (modified calcined diatomite: M-D) was significantly improved. The methylene blue trihydrate (MB) adsorption capacity of the optimal M-D sample reached 45.76 mg/g, which was 2.73 times higher than that of the sample prepared without the alkali treatment. The substantial enhancement in adsorption performance of M-D was mainly attributed to the abundant SiO 3 2− species which was primarily generated during the NaOH pretreatment. SiO 3 2− species are helpful for generating silicate substances with a larger specific surface area. By regulating the amount of NaOH, it was feasible to control the morphology/nanostructure and composition of the final materials. Well-developed flower-like nanoclusters was synthesized on the surface of C-D, resulting in higher specific surface area and adsorption capacity. This work paves the way to the value-added application of natural diatomite resources via providing an efficient modification method to optimize the properties of C-D. • A novel calcined diatomite materials was successfully fabricated. • The calcined diatomite materials exhibited superior adsorption property. • SiO 3 2− played a dominated role in the modification for calcined diatomite. • The modification process of NaOH pretreatment were proposed. [ABSTRACT FROM AUTHOR]

Pretreatment is commonly used to reduce recalcitrance of the lignin-carbohydrate matrix. In this study, leading pretreatment technologies, including dilute sulfuric acid, liquid hot water, alkaline, and organosolv pretreatments, were applied to the selected Populus trichocarpa genotype with relatively low lignin content to elucidate cellulose physicochemical property changes and digestibility-related factors. Pretreated Populus trichocarpa (BESC 131) exhibited higher accessibility and glucose yield than the untreated biomass. Chemical composition and Fourier transform infrared (FTIR) analysis results revealed that hemicellulose and lignin were removed to a varying extent depending on the pretreatment techniques applied. The degree of polymerization of the cellulose was decreased to the largest extent after dilute acid pretreatment, followed by organosolv, alkaline, and liquid hot water pretreatments. Cellulose crystallinity index was slightly changed after the pretreatments; however, its differences were not remarkable between those pretreatment techniques. Among four different pretreatments, organosolv was the most effective pretreatment technology in terms of sugar release, which was three times higher than that of the untreated native biomass. Among all of the tested cell wall traits, the lignin content of Populus trichocarpa was the most remarkable feature associated with glucose release, though Populus trichocarpa recalcitrance was not solely dependent on any single factor. [ABSTRACT FROM AUTHOR]

Fast pyrolysis is a comparable technology with enzyme or acid hydrolysis for saccharification of biomass. The low yield of levoglucosan and the formation of inhibitors to biocatalysts from lignocellulose hamper the fermentable utilization of pyrolysate. In this study, aiming to enhance the production of levoglucosan, dilute alkali pretreatment was performed prior to fast pyrolysis of corncobs. The yield of levoglucsoan from pretreated corncobs was significantly improved (34.8%) as compared to that from un-treated corncobs (3.0%), which was mainly attributed to the removal of alkaline and alkaline earth metals as well as lignin fraction by NaOH pretreatment. Conversely, NaOH pretreatment suppressed the formation of acids (from 11.1 to 2.2%), furans (from 2.5 to 2.0%), ketones (from 15.7 to 9.8%) and phenols (from 4.8 to 1.3%), which were common inhibitors to the biocatalysts. Accordingly, NaOH pretreatment facilitated further selective conversion of biomass in fast pyrolysis and made the pyrolysate more fermentable. [ABSTRACT FROM AUTHOR]

Silicon (Si) is known to alleviate biotic and abiotic stress, and to reduce the development of fungal diseases in a number of different pathosystems. Biochar-based Si fertilizers, especially highly efficient alkali-enhanced biochar for recycling phytolith, has been recently proposed as a stress-alleviating amendment but its evaluation on plant disease development has not been investigated. In this study, several biochar–based Si fertilizers including raw biochar without alkaline enhancement (0 KB), alkali-enhanced biochars with KOH (10 KB), CaO (10CB), and K 2 CO 3 (10K2B) along with commonly-used mineral Si fertilizer wollastonite (WO) and calcium silicate slag (SL) were evaluated in a controlled potting study for their potential to suppress gray leaf spot (Magnaporthe oryzae) development in perennial ryegrass (Lolium perenne L.). Application of 10 KB (at 0.22% rate) increased tissue Si content by 57% compared to the control. The 1% application rate of biochar enhanced ryegrass tissue Si content by 11, 8, 34 and 27% in 0 KB, 10 KB, 10K2B and 10CB compared to 0.22% rate correspondingly. Analysis of area under disease progress curve (AUDPC) showed that gray leaf spot development was reduced by 65–77% with treatments of 0 KB, 10CB and 10 KB, 10K2B at 0.22% rate, and 58–67% for treatments of 10 KB and 10CB at 1% rate compared with the control. At the same application rate (0.22%), 10CB and 10K2B showed better performance in suppressing disease severity than commonly-used wollastonite and calcium silicate slag. Overall, soil amendments with alkali-enhanced biochar-based Si sources increased Si tissue concentration and reduced gray leaf spot development in perennial ryegrass. • Rice straw biochar Si source amendments significantly increased perennial ryegrass Si contents. • KOH- or K 2 CO 3 -enhanced biochar improved Si uptake compared to non-enhanced biochar. • Biochar-based Si sources suppressed perennial ryegrass gray leaf spot. • Alkali-enhanced biochar Si sources could be used to manage perennial ryegrass gray leaf spot. [ABSTRACT FROM AUTHOR]

Lignin is one of the major components of plant cell wall, and it can provide sufficient strength and hardness to plant cells while avoiding biological damage and water erosion. In recent years, studies on the lignification process and delignification of plant tissues have received extensive attention from scholars. A large number of studies have been carried out to determine the removal of lignin after pretreatment by conventional wet chemical analysis. The lignin content and distribution of biomass resources such as crop straw directly affect its conversion and utilization efficiency. It’s meaningful to develop multi-scale and in situ analysis to identify lignin distribution and quantification on delignified plant cell wall for bio-resource commercial utilization. In this paper, we studied an in situ analysis method to visualize changing of lignin distribution in the alkali pretreated corn straw internodal transverse section based on Fourier transform infrared (FTIR) microspectroscopic imaging, with a fast non-negativity-constrained least squares (fast NNLS) fitting. We collected the middle of the 6th node of fresh jointing stage corn straw. Corn straws were pretreated for series of times (0 , 5 , 30, 60 min) by 2% NaOH solution at 100℃. A paraffin embedding method was used to produce 18 μm-thick transverse sections for each sample. Then, the sections were transferred onto ZnS windows for FTIR microspectroscopic imaging. We acquired FTIR spectra of major components of corn straw for fast NNLS fitting. We also milled whole straws to 0.069 mm and pretreated in the same condition as sections to determine structure carbohydrate. The data of FTIR microspectroscopic images and FTIR spectra were processed by Savizky−Golay smoothing within 5 points, SNV, and automatic Whittaker filter baseline to correct baseline and offset. K-means cluster algorithm was used to distinguish various tissues including epidermis, vascular bundles and parenchyma cells. Fast NNLS fitting was carried out to calculate the lignin concentrations in pixels. For comparison between different pretreated times, lignin concentration in pixels was calibrated according to the sum of content of all components based on laboratory analysis. The lignin content by laboratory analysis decreased with the increasing of the pretreated time, and the lignin degradation rate was larger at the initial stage of the reaction. The lignin content in the epidermis, vascular bundle and parenchyma cells of the samples showed a decreasing trend with the increasing of pretreatment time, and the trends of lignin changing in the three tissues were consistent with the trend of laboratory analysis. By comparing laboratory analysis with fast NNLS fitting results, the results show that the FTIR microspectroscopic imaging combined with fast NNLS could locate and quantify the distribution of lignin in various tissues, and the trend of lignin changing calculated by fast NNLS fitting is the same as the laboratory chemical analysis results. The study demonstrated that FTIR microspectroscopic imaging combined with fast NNLS fitting could be successfully applied to in situ visualize lignin distribution within corn straw pretreatment. The characterization method provides reference for the lignin research of corn stover pretreatment and the study of lignin degradation during straw pretreatment. [ABSTRACT FROM AUTHOR]

Cotton stalks (CS) are considered a good candidate for fuel-ethanol production due to its abundance and high carbohydrate content, but the direct conversion without pretreatment always results in extremely low yields due to the recalcitrant nature of lignocelluloses. The present study was undertaken to investigate the effect of various chemical and physicochemical pretreatment methods, i.e., alkali, microwave-assisted acid, organosolv, hydrothermal treatment, and sequentially organosolv and hydrothermal pretreatment, on chemical composition of CS and subsequent ethanol production applying pre-hydrolysis and simultaneous saccharification and fermentation (PSSF) at high solid loading. The best results in terms of ethanol production were achieved by the sequential combination of organosolv and hydrothermal pretreatment (32.3 g/L, using 15% w/v substrate concentration and 6 h pre-hydrolysis) with an improvement of 32% to 50% in ethanol production compared to the other pretreatments. Extending pre-hydrolysis time to 14 h and increasing substrate concentration to 20% w/v, ethanol production reached 47.0 g/L (corresponding to an ethanol yield of 52%) after 30 h of fermentation. [ABSTRACT FROM AUTHOR]

Highlights • Maize cobs released more COD in seawater than in distilled water. • NaOH pretreatment promoted COD releasing, both in seawater and in distilled water. • Saline CW with maize cobs lixivium removed NO 3 -N efficiently with low effluent COD. Abstract This study aims to investigate the releasing behaviors of maize cobs with or without alkali (i.e. NaOH) pretreatment in seawater and distilled water, and to evaluate the effects of maize cobs addition (solid biomass and lixivium) on nitrogen removal in saline constructed wetland (CW) treating marine recirculating aquaculture system (RAS) effluents. Results revealed NaOH-treated maize cobs released carbon more efficiently, whether in seawater or in distilled water. Compared to distilled water, seawater conditions promoted carbon releasing. CW with maize cobs biomass and lixivium addition had high NO 3 -N removal efficiencies without significant difference, i.e. 94.9 ± 6.0% and 87.1 ± 13.2%, respectively. While CW with maize cobs biomass addition had higher effluent COD concentrations (16.3 ± 3.6 mg L−1) compared with those adding lixivium (2.1 ± 0.4 mg L−1). The study suggested adding maize cobs lixivium to be feasible and effective way to enhance nitrogen removal in saline CW. [ABSTRACT FROM AUTHOR]

Highlights • A large amount of organic matter is released during microalgal powder decomposition. • Adding alkali pre-treated microalgal powder to CW improved denitrification rate. • Limited side effects on the removal of COD and TP were observed. Abstract This study explores the feasibility of using microalgae biomass (Chlorella sp.) as a carbon source to increase the denitrification efficiency of horizontal subsurface flow constructed wetlands (HSSF-CWs). The results show that a large amount of organic matter is released in the process of microalgal powder decomposition. After alkali pretreatment, enhancements in the cumulative release amount (from 51.3 mg·L−1 to 106.8 mg·L−1) and stable release rate (from 0.13 mg·L−1·h−1 to 0.25 mg·L−1·h−1) of organic matter were observed. The addition of microalgal powder with alkali pretreatment to HSSF-CWs improved the removal of nitrate (NO 3 −-N) by 27.9% and total nitrogen (TN) by 17.7% compared to that without addition. There were limited side effects influencing the release of COD and TP in the effluent. For the treatment of wastewater with a low C/N ratio, it is feasible to add microalgal biomass as an external carbon source to HSSF-CWs to improve denitrification efficiency. [ABSTRACT FROM AUTHOR]

Graphical abstract Both ultrasound and alkali pretreatment could facilitate enzymolysis of yeast β-glucan by loosening aggregated structure and enlarging its surface area, and increased water-soluble yeast β-glucan yield to 32.3% and 36.2%, respectively. Highlights • Ultrasound and alkali treatments reduced YG size from 8.80 μm to 1.77 and 7.19 μm. • Ultrasound cavitation disrupted YG aggregates and exposed its internal structure. • Alkali penetrated into YG particles and broke them into flakes by cleaving linkages. • Both treatments facilitated YG enzymolysis by adding surface area and contact point. • Ultrasound- and alkali-assisted enzymolysis enhanced WSYG yield to 32.3% and 36.2% Abstract This study investigated the effects and related mechanisms of ultrasound- and alkali-assisted enzymolysis on production of water-soluble yeast β-glucan (WSYG). Results indicated that ultrasound and alkali pretreatments reduced the particle size of yeast β-glucan (YG) from 8.80 μm to 1.77 and 7.19 μm, respectively. Ultrasound-induced cavitation disrupted YG aggregates to a coarse appearance and exposed internal structure. Alkali penetrated into YG particles and broke the YG aggregates into a flake-like morphology by cleaving the linkages within YG chains. Both pretreatments facilitated enzymolysis by enlarging the YG surface area and increased the WSYG yield to 32.3% and 36.2%, respectively. Meanwhile, the purity of WSYG reached 98.8% after zymoprotein removal by DEAE-Sepharose fast flow column. This work not only provides a green method for producing high-purity and high-yield WSYG, but also reveals the mechanisms of ultrasound and alkali pretreatments for improving enzymolysis efficiency by loosening the YG structure and increasing the surface area. [ABSTRACT FROM AUTHOR]

Utilisation of crop residues is limited due to their low energy and high ash content. This study aimed to develop a method for enabling the use of residual agricultural biomass through acid or alkali pretreatment followed by torrefaction. Pepper stems were treated with hydrochloric acid or sodium hydroxide for a brief period of time and rinsed with distilled water. Untreated and acid-pretreated samples had cellulose contents of 43.85% and 36.57%, respectively. The lignin content in the alkali-pretreated samples (22.74%) was lower than that in untreated samples (27.40%). Mass yield decreased with torrefaction temperature, ranging from 86.19% to 49.89%. However, alkali-treated samples showed smaller changes in mass yield (70.31–60.43%) than other samples. Regarding calorific value, untreated samples exhibited the highest increase (26.37%), whereas alkali-treated samples showed a modest increase of 10.62%. Chlorine content was higher in acid-compared with alkali-treated samples but decreased with temperature. Our study demonstrated that agricultural by-products can be used as energy sources through acid or alkali pretreatment prior to torrefaction. Future studies should explore a variety of agricultural by-products and consider pretreatment with different acids or alkalis, such as sulfuric acid and potassium hydroxide. • Pepper residual stems were pre-treated by acid or alkali conditions. • Biomass was torrefied at relatively low temperatures after pretreatment. • Wood chemical changes were confirmed through acid or alkali pretreatment. • Biomass chlorine content was reduced by acid or alkali pretreatment. • Pre-treatment improved the properties of agrobyproduct as fuel material. [ABSTRACT FROM AUTHOR]

• NaOH and CTAB pretreatment increased hydrolysis efficiency of wheat straw. • Increment of xylan and lignin removal of wheat straw was 8.2% and 25.8%. • Synergy between CTAB and NaOH enhanced wheat straw' accessibility. The alkali pretreatment has been widely applied for various lignocellulose to enhance its cellulosic utilization through addressing textural recalcitrance. However, the large consumption of alkali makes it challenging to obtain the desired results but also brings a series of environmental pollution. Hence, trace surfactants were used as auxiliaries to improve the sugar production of wheat straw (WS) in this work. The results displayed that the delignification and xylan removal of WS has been highly increased from 18.7% to 44.3% and from 75.6% to 83.8% with the addition of 10 g/L cetyltrimethylammonium bromide (CTAB) in 5 g/L NaOH pretreatment, leading to the collapse of tightly clustered structures in WS. Finally, the positive changes of intensifying lignin's extraction by CTAB enhanced the enzymatic hydrolysis efficiency from 59.5% to 85.9%. This novel pretreatment improved the economic value of WS and provided favorable evidence for a case of utilization of CTAB in alkali pretreatment. [ABSTRACT FROM AUTHOR]

The heat release of coal oxidation lead to the thermal decomposition of carboxylic groups, which include carboxylic acid and carboxylate. However, few researchers have studied the effect of the decomposition of intrinsic carboxylate structure on coal self-ignition process. In this work, different coal samples were selected and treated with alkali solutions to form organic carboxylate structures, and the thermal decomposition of the raw and alkali-treated coals followed by the room temperature oxidation process were analyzed. The effect of the carboxylate structures on the thermal behavior, elemental distribution, and functional groups of coal was also studied by means of TGA, FTIR, XPS and EPR. The results showed that the carboxylic groups in coal were transformed into carboxylate structures by ion exchange. In addition, highly reactive free radical active sites were produced and accumulated along with the decomposition of carboxylates, thus accelerating the self-heating of coal. In the room-temperature oxidation experiment, the temperature of alkali-treated Wulan coal was spontaneously raised by 13.9℃, while that of raw coal was 4.3 ℃. The results showed that the thermal decomposition of organic carboxylate played an important role in promoting the spontaneous combustion of coal, and acid pretreatment could be a potential method to effectively inhibit the coal self-ignition process. • Alkali-treated sample was found with higher reactivity in low temperature oxidaiton. • Opposite effect of carboxylate was found at different temperatures in oxidation. • Carboxylate in coal remarkable promoted the generation of free radical active sites. • Carboxylate has a greater effect than carboxylic acid in low temperature oxidation. [ABSTRACT FROM AUTHOR]

Ethanol production from rice husk by simultaneous saccharification and fermentation using Mucor hiemalis was investigated. To reach the maximum ethanol production yield, the most important influencing factors in the pretreatment process, including temperature (0-100°C), NaOH concentration (1-3 M), and the pretreatment time (30-180 min), were optimized using an experimental design by a response surface methodology (RSM). The maximum ethanol production yield of 86.7 % was obtained after fungal cultivation on the husk pretreated with 2.6 M NaOH at 67°C for 150 min. This was higher than the yield of 57.7% obtained using Saccharomyces cerevisiae as control. Furthermore, fermentation using M. hiemalis under the optimum conditions led to the production of a highly valuable fungal biomass, containing 60 g glucosamine (GlcN), 410 g protein, and 160 g fungal oil per each kg of the fungal biomass.

Castor, a non-edible oil crop that flourishes even under extreme cultivation conditions, can be cultivated in wastewater with a lower cultivation cost than similar plants, e.g., rapeseed and soybean. This plant, containing seeds and lignocellulosic residues, has a promising perspective for biofuel production. The oil extracted from the seeds is inexpensive and can be efficiently converted to biodiesel, while the lignocellulosic parts are suitable for ethanol production after pretreatment with NaOH. Biodiesel typically produced from the fossil-based methanol; however, it can also be produced from the ethanol. In this study, ethanol used for biodiesel production is produced from the lignocellulosic residues (scenario 1), which are more sustainable and environmentally friendly; the process was compared with that of the methanol (scenario 2). In this study, techno-economic analyses were used to compare the technical and economic aspects of producing biodiesel from methanol and the produced ethanol. Simulations of the processes were carried out by Aspen plus software, and economic studies were conducted by Aspen Economic Analyzer. The prices of produced ethanol as a byproduct in scenarios 1 and 2 were USD 0.701 and 0.693 per liter, respectively, which are greater than that of gasoline. The prices of biodiesel produced as a primary product for scenarios 1 and 2 are USD 0.410 and 0.323/L, lower than the price of diesel in the Middle East region. The profitability indices for scenarios 1 and 2 are 1.29 and 1.41, respectively. Therefore, despite environmental benefits, the biorefinery based on producing biodiesel from methanol is more economically feasible than that produced from ethanol.

In this work, Bana grass, a species of Napier grass (P. purpureum × P. americanum hybrid) which contains 60.2% cellulose, 23.8% hemicellulose and 8.2% lignin, was tested in the laboratory for lignin removal or delignification. Two processes of delignification were combined. Firstly, alkali pretreatment was used to determine the best conditions for the first stage of delignification. Secondly, the selected pretreated material, which was obtained from the best conditions for the first stage, was tested with the ozonolysis process. In the first stage of alkali pretreatment, five concentrations of sodium hydroxide (NaOH) from 0.5 to 10.5 wt.% were used. This research considers the ratio of cellulose to lignin because the ratio should be high for good lignocellulose. For untreated Bana grass, the ratio of cellulose to lignin is 7.3. After the first stage of alkali pretreatment, the maximum cellulose and lignin ratio is at 12.6 with 5.5 wt.% NaOH, and the amount of lignin elimination is 5.2%. The second stage is to pretreat lignocellulose with ozone. The concentration of ozone in the experiment is 1000 mg/h, and the pretreatment time is 0-30 min. Increasing time leads to higher lignin removal, but there is still cellulose in the material. Ozone pretreatment increases the ratio of cellulose to lignin for the first stage pretreatment material to 93.8. Ozone pretreatment alone cannot eliminate lignin from Bana grass, but it is better if it reacts with a sodium hydroxide solution. A combination of alkali and ozone pretreatment gives a high ratio of cellulose to lignin. From the results of the inhibitor examination, it is found that there is no detection of acetaldehyde, but total phenolics are detected for the pretreatment condition. These toxins can be eliminated by washing with water. [ABSTRACT FROM AUTHOR]

In this study, total eight distinct Miscanthus accessions were collected from the cadmium (Cd)-supplied soil pots, and mild alkali pretreatments (0.5%, 1% NaOH) were then performed to enhance biomass enzymatic saccharification. Due to large Cd accumulation, all Miscanthus accessions showed significantly reduced cellulose levels and features (CrI, DP) with much increased hemicellulose and pectin contents in the mature stems. Under mild alkali pretreatments, all Miscanthu s samples exhibited largely increased hexoses yields released from enzymatic hydrolysis, and one desirable accession had an almost complete biomass saccharification with the hexoses yield at 100% (% cellulose). Notably, the biomass residues remained from enzymatic hydrolysis upon 1% NaOH pretreatment could absorb 73–96% Cd (% of total), suggesting an applicable approach for Cd phyto-remediation. Hence, a hypothetic model was proposed to elucidate that the enhanced biomass saccharification should be mainly due to much reduced cellulose CrI and DP in the Cd-accumulated Miscanthus accessions. [ABSTRACT FROM AUTHOR]

In this work, the effect of water-soluble lignin on the enzymatic saccharification of alkali-pretreated wheat straw was investigated using soluble fraction (WAL) and sulfomethylated insoluble fraction (SAL) of alkaline lignin from the pretreatment spent liquor as additives. Results showed the total sugar recovery was improved for pretreated solids but was inhibited for bleached substrate with adding a certain amount of WAL or SAL. The interaction between adsorption domain of cellulase and water-soluble lignin was considered to be the potential reason for reducing the non-productive adsorption of residual lignin to cellulase. SAL was more efficient on enhancing the enzymatic saccharification than WAL, and the effect of WAL and SAL on glucan recovery was rather different from that of xylan recovery. Based on the obtained results, a strategy to improve the enzymatic saccharification of lignocellulosic biomass by adding water-soluble lignin prepared from alkali pretreatment spent liquor was proposed. [ABSTRACT FROM AUTHOR]

This study focused on poplar (Populus tomentosa) catkin fiber as a new resource for bioethanol production via enzymatic hydrolysis. The poplar catkin fiber was found to have advantages of relatively high α-cellulose content (44.5%), and low lignin content (2.9%), which indicated the potential for facile enzymatic hydrolysis. The results indicated that the pretreatment improved the cellulose-to-glucose conversion yield (CGCY), the high concentration alkaline pretreatment resulted in highest CGCY (83.3%), followed by dewaxing (31.5%), dilute alkaline (29.8%), and dilute acid pretreatment (24.4%) after enzymatic hydrolysis with cellulase of 15 filter paper units per gram glucan, while the poplar catkin fiber only achieved 18.7% of CGCY by enzymatic hydrolysis after 48 h at 50 °C without any pretreatment. [ABSTRACT FROM AUTHOR]

In Europe, the agricultural biogas sector is currently undergoing fast developments, and cattle manure constitutes an important feedstock. Batch dry digester processes with leachate recirculation prove to be particularly interesting for small-scale plants. However, their startup being relatively slow, the process could be facilitated by co-digestion with energy crops. In this study, Miscanthus x giganteus was chosen for its high biomass yields and low input requirements. The carbohydrate accessibility of this lignocellulosic biomass is limited but may be improved with alkali pretreatment. The efficiency of lime (CaO) pretreatment with low water addition on the biochemical methane potential (BMP) of miscanthus was investigated through two experimental designs (CaO concentrations ranged between 2.5 and 17.5% and pretreatment lasted 1, 3, or 5 days). The pretreated miscanthus was then co-digested with cattle manure in dry leach bed reactors. CaO pretreatments led to a 14–37% improvement of miscanthus BMP, and a 67–227% increase in the first-order kinetics constant; a high contact time was shown to favor methane production. According to these results and to industrial requirements, miscanthus was pretreated with 5 and 10% CaO for 5 days, then co-digested with manure in dry leach bed reactors. Nevertheless, the promising results of the BMP tests were not validated. This could be related to the high water absorption capacity of miscanthus. [ABSTRACT FROM AUTHOR]

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In this study, sugarcane bagasse (2 mm) was pretreated with 2.5% NaOH followed by steaming at 121°C for various time periods. Maximum cellulose content of 81% and delignification of 68.5% were achieved by soaking bagasse in 2.5% NaOH with a residence time of 1 h at room temperature followed by steaming at 121°C for 30 min residence time. The pretreated substrate was analyzed by SEM and FTIR to study the structural modification and functional group of the untreated and pretreated substrates. The pretreated substrate was saccharified by commercial cellulase enzyme depicting 106 µm mesh size of substrate yields maximum saccharification rate. The saccharified material was fermented by Saccharomyces cerevisiae and Pichia stipitis in mono- and co-culture modes. Maximum product yield (Yp/s) was observed by monoculture using Saccharomyces cerevisiae after 96 h of fermentation period. [ABSTRACT FROM AUTHOR]

In this study, alkaline pretreatment at a bench scale (15-L capacity) was performed to obtain a higher solid residue for the SSF (simultaneous saccharification and fermentation) of Miscanthus sacchariflorus “Goedae-Uksae 1” (GU) under the following conditions: 1 M NaOH concentration, 150 °C, and 60 min residence time. Compositional analysis and scanning electron microscope analysis revealed the pretreatment to be highly effective for achieving delignification and morphological changes. Spiral impellers were used for the rapid liquefaction of pretreated GU into slurry, and no additional nutrients were added to the fermentation mixture to reduce overall process costs. The SSF was subsequently conducted in a laboratory-scale fermenter (5-L capacity) for 108 to 120 h with 12% and 16% glucan containing pretreated GU. Consequently, 62.8 g/L and 81.1 g/L of ethanol were obtained. Based on these data, the theoretical ethanol yields from 1 kg of GU (dry weight base) were estimated at 164.6 to 171.1 g/L.

Bioethanol production from lignocellulosic biomass provides an alternative energy-production system. Sorghum bicolor stem is a cheap agro-waste for bioethanol production. In this study, response surface methodology (RSM) was used to optimize alkali pretreatment conditions for sorghum bicolor stem with respect to substrate concentration, NaOH concentration and pretreatment time based on a central composite rotary design. The main goal was to achieve the highest glucose and xylose yields after enzymatic hydrolysis. Under optimum conditions of pretreatment i.e. time 60.4 min, solid loading 4.2%, and NaOH concentration 1.7%, yields of 98.94% g glucose/g cellulose and 65.14% g xylose/g hemicelluloses were obtained. The results of a confirmation experiment under the optimal conditions agreed well with model predictions. Pretreatment of sorghum bicolor stem at the optimum condition increased the glucose and xylose yields by 7.14 and 3.02 fold, respectively. Alkali pretreatment showed to be a great choice for the pretreatment of sorghum bicolor stem.

Cotton stalks (CS) are considered a good candidate for fuel-ethanol production due to its abundance and high carbohydrate content, but the direct conversion without pretreatment always results in extremely low yields due to the recalcitrant nature of lignocelluloses. The present study was undertaken to investigate the effect of various chemical and physicochemical pretreatment methods, i.e., alkali, microwave-assisted acid, organosolv, hydrothermal treatment, and sequentially organosolv and hydrothermal pretreatment, on chemical composition of CS and subsequent ethanol production applying pre-hydrolysis and simultaneous saccharification and fermentation (PSSF) at high solid loading. The best results in terms of ethanol production were achieved by the sequential combination of organosolv and hydrothermal pretreatment (32.3 g/L, using 15% w/v substrate concentration and 6 h pre-hydrolysis) with an improvement of 32% to 50% in ethanol production compared to the other pretreatments. Extending pre-hydrolysis time to 14 h and increasing substrate concentration to 20% w/v, ethanol production reached 47.0 g/L (corresponding to an ethanol yield of 52%) after 30 h of fermentation.

Biodiesel is a renewable and substitute fuel to diesel engines. The main limit for adoption of biodiesel on industrial scale as an alternative fuel is the high cost of its synthesis process using raw methanol during transesterification reaction. Using bio-refinery approach and inexpensive high-quality oil feedstock is an effective means to produce low-cost biodiesel. In this study Saussurea heteromalla a novel non-edible seed with high oil contents (30 wt%) was subjected first time to integrated synthesis of biodiesel and ethanol. Transesterification and simultaneous saccharification along with fermentation process was applied to produce biodiesel and ethanol respectively. Alkaline pretreatment with sodium hydroxide (8% w/v) at 100 ° C was used to enhance ethanol yield from 30% to 80%. A highest biodiesel yield of 99% was achieved via optimized parameters of 6:1 alcohol to oil ratio with 0.26 wt% catalyst in 55 min time at 65 ° C temperature using Response Surface Methodology. It was observed that 112.2 ± 1.6 g of biodiesel and 42.0 ± 0.5 g of ethanol were produced using 1 kg of Saussurea heteromalla seed oil. In addition, the fuel properties of prepared biodiesel were in accordance to ASTM D 6751 and EN 14214 standards. [ABSTRACT FROM AUTHOR]

Glycyrrhiza glabra residue (GGR) contains 30.5% cellulose and 23.0% hemicellulose and can be considered as a promising low-cost and non-edible feedstock for production of ethanol. For the first time, GGR was subjected to inexpensive sodium hydroxide (SH) pretreatment to enhance fermentable sugars production through enzymatic hydrolysis and subsequent utilization by fungus Mucor hiemalis . The pretreatment was carried out at 5% (w/v) solid loading and different temperatures (0, 28 and 110 °C) with 2, 4, 6, 8 and 10% (w/v) SH solutions. When applying no pretreatment, the glucose and ethanol production yields through separated hydrolysis and fermentation of GGR were only 13.9% and 14.3%, respectively. However, a major improvement was achieved after alkali pretreatment of GGR and the maximum hydrolysis yield of 93.7% was observed when the substrate was pretreated with 4% SH solution at 28 °C for 24 h. Consequently, fermentation of the SH pretreated materials by M. hiemalis led to a maximum 5.9-fold increase in ethanol production yield (∼217 kg per ton of GGR), which was slightly higher than the ethanol yield through the yeast Saccharomyces cerevisiae (∼207 kg per ton of GGR). Semi-quantitative analyses of the substrate after pretreatment indicated that crystallinity reduction and expanded surface area were the main reasons for the observed improvements. In brief, the results revealed that SH pretreatment (4% w/v) at room temperature is an effective strategy to valorize GGR to ethanol through hydrolysis and fermentation by fungus M. hiemalis . [ABSTRACT FROM AUTHOR]

The sweet corn planted areas in Thailand are estimated more than 2.8 million acres and they are also likely to increase by an average about 0.9% each year. These lead to increase the amounts of sweet corn residuals such as trees, leaves, cobs and husks, are accumulated into the fields for burning management more than 35,000 tons per year. The renewable energy production by using biogas technology should be instead of burning for treatment of sweet corn residuals. Seeds, corncobs and cornhusks were used as materials for dry anaerobic digestion using co-digestion technology with 3 types of dung; pig dung, cow dung and goat dung. Corncobs and cornhusk were grinded into 2-3 cm of length and pretreated with alkali pretreatment at room temperature for 48 hr. After pretreatment, hemicellulose and lignin were reduced form original plants by using 2%(w/v) of NaOH. The digestions were performed at 1:1 of dung and corn residual ratio, at 37±2 ๐ C, 74±3% humidity, 25% of initial total solid, and C/N ratio at 3-10:1. The results showed that anaerobic co-digestion between pig dung/seed (PS), goat dung/husk (GH) and cow dung/husk (CH) showed the highest efficiency of COD removal at 79.80%, 74.37% and 72.49%, respectively. While GH, goat dung/cob (GC), and PS had maximum biochemical methane potential at 68.20%, 60.58% and 24.11%, respectively. Moreover, GH had highest methane concentration at 46 vol%, and also produced the volume of methane at 5,045.8 ml/gVS. These values were equivalent to heating value at 16.53 MJ/m3. Meanwhile pig dung/seed (PS) and cow dung/cob (CC) had methane concentration at 19 vol% and 9.10 vol%, respectively. However, the amount of H 2 S at 30 day of dry digestion using pig dung, cow dung and goat dung were equal to 160 ppm, 58.33 ppm and 25 ppm, respectively. [ABSTRACT FROM AUTHOR]

Biomethane was produced from water hyacinth ( Eichhornia crassipes (Mart.) Solms), an aquatic weed plant, comprising of cellulose, hemicellulose and lignin by using two steps of methods. The first was that fresh and dry water hyacinth in the length of 1 cm, were pretreated with 2 different alkali solutions; 2%(w/v) of NaOH and 10% (w/v) of Lime. The optimum condition was selected from 100, 120 and 140oC for 4 hr at ratio of 1g plant per 15 ml of treatment solution. The yields of sugar from NaOH pretreatments were higher than lime conditions. The highest of sugar yield at 60 g sugar /g substrate was observed from 140oC by using dry water hyacinth, whereas fresh hyacinth had yield at 36.7 g sugar /g substrate . The second method was 12 sets of anaerobic co-digestions with 3 types of dung; pig dung, elephant dung and bat dung, and 2 types plants; fresh and dry hyacinth that pretreated by sodium hydroxide and calcium hydroxide. The mixtures of sugar solution and treated plant solid from both hyacinths were used as substrates by using 200 ml of waste water from sweet corn industrial as starter. The co-digestions were achieved at 1:1 ratio of dung and mixture solutions and at 37±2°C under anaerobic condition for 45 days. The COD removal in rang of 51-69% were absorbed from all 12 conditions. The digestions from all lime treated plants showed higher methane concentration than NaOH treated plants. The lime treated fresh hyacinth had highest values of biochemical methane potential (BMP) and methane concentration were at 59.3% and 63.65 vol.%, respectively. They were equivalent to heating value at 12.58 MJ/m 3 . The second was lime treated dry hyacinth that showed 32.4% BMP and 43.15 vol.% of methane, respectively. [ABSTRACT FROM AUTHOR]

Coking coal has been employed for coking wastewater adsorption treatment. The modification and adsorption of coking coal pretreated by alkali solution is discussed and compared in this study. Results demonstrated OH- could react with -COOH, -OH and minerals, which resulted in coal surface variations. As the hydroxide concentration is increased, surface hydrophobility increased and the zeta potential became less negative. A coal sample pretreated by 0.1 mol/L NaOH solution had the highest surface area and pore volume. The adsorption ability of the samples was improved significantly as surface changes. The coal sample pretreated by 0.1 mol/L NaOH solution had the highest adsorption capacity, and followed pseudo-second-order kinetics. [ABSTRACT FROM PUBLISHER]

Lyocell fabrics were pretreated with NaOH, KOH and LiOH and subsequently crosslinked with three urea-formaldehyde based crosslinkers DMDHEU, DMeDHEU and DMU. The mechanical properties varied with the alkali concentration in fabrics crosslinked after pretreatment with 2-8 mol/l NaOH and 4 mol/l LiOH. In fabrics crosslinked after pretreatment with 2-8 mol/l KOH and 1-3 mol/l LiOH, in contrast, the mechanical properties were relatively insensitive to the alkali concentration. The difference in effects is attributed to the alkali influence on the accessibility of crosslinker in fiber structures. The NaOH and 4 mol/l LiOH pretreatments increase the accessibility of crosslinker but the KOH and 1-3 mol/l LiOH pretreatments do not appear to change accessibilities to the same extent. The results underscore the importance of alkali choice and process control in the pretreatments of lyocell. Both NaOH and KOH may be used to good effect. However, lyocell is more sensitive to changes of alkali concentration in NaOH treatments as compared to KOH pretreatments. Thus, the use of NaOH in pretreatments of lyocell will require a greater degree of monitoring and control of alkali concentrations as compared to when KOH is used. [ABSTRACT FROM AUTHOR]