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The biodegradation kinetics of paper materials with various chemical additives was studied, focusing on their potential tunability. Paper materials with additives, including retention aid, hydrophobic agent, and wet and dry strength agents, were explored in two forms: disintegrated fiber and paper form. Using the Gompertz equation, biodegradation kinetics were modeled to calculate the lag phase, initial biodegradation rate, and ultimate biodegradation extent. All paper materials showed higher biodegradation extents than microcrystalline cellulose (MCC) due to the highly biodegradable nature of hardwood bleached pulp. Disintegrated paper materials exhibited similar lag phase values and ultimate biodegradation to MCC regardless of treatment, while punched paper materials showed noticeable differences, suggesting that fiber disintegration plays a critical role in initiating biodegradation. Hydrophobic and wet strength treatments, such as alkyl ketone dimer (AKD) and wetstrength agents (PAE), respectively, significantly increased the lag phase, but their ultimate biodegradation extent remained intact. These findings highlight that the biodegradability of paper materials can be preserved even after chemical treatments, underscoring their environmentally friendly potential. [ABSTRACT FROM AUTHOR]

• A metaproteomics-based comparison of microbial degradation from ASP to AB was conducted. • Upgrading from ASP to AB increased lignocellulose degradation rates by 18.49-46.52%. • The upgrade from ASP to AB improved diversity of CAZyme-producing microbes. • AB but not ASP can produce the key enzyme for acetate conversion. • AB was superior to ASP for compost decomposition with higher cellulose. Composting presents a viable management solution for lignocellulose-rich municipal solid waste. However, our understanding about the microbial metabolic mechanisms involved in the biodegradation of lignocellulose, particularly in industrial-scale composting plants, remains limited. This study employed metaproteomics to compare the impact of upgrading from aerated static pile (ASP) to agitated bed (AB) systems on physicochemical parameters, lignocellulose biodegradation, and microbial metabolic pathways during large-scale biowaste composting process, marking the first investigation of its kind. The degradation rates of lignocellulose including cellulose, hemicellulose, and lignin were significantly higher in AB (8.21%-32.54%, 10.21%-39.41%, and 6.21%-26.78%) than those (5.72%-23.15%, 7.01%-33.26%, and 4.79%-19.76%) in ASP at three thermal stages, respectively. The AB system in comparison to ASP increased the carbohydrate-active enzymes (CAZymes) abundance and production of the three essential enzymes required for lignocellulose decomposition involving a mixture of bacteria and fungi (i.e., Actinobacteria, Bacilli, Sordariomycetes and Eurotiomycetes). Conversely, ASP primarily produced exoglucanase and β-glucosidase via fungi (i.e., Ascomycota). Moreover, AB effectively mitigated microbial stress caused by acetic acid accumulation by regulating the key enzymes involved in acetate conversion, including acetyl-coenzyme A synthetase and acetate kinase. Overall, the AB upgraded from ASP facilitated the lignocellulose degradation and fostered more diverse functional microbial communities in large-scale composting. Our findings offer a valuable scientific basis to guide the engineering feasibility and environmental sustainability for large-scale industrial composting plants for treating lignocellulose-rich waste. These findings have important implications for establishing green sustainable development models (e.g., a circular economy based on material recovery) and for achieving sustainable development goals. [Display omitted] [ABSTRACT FROM AUTHOR]

The study was designed to explore the efficiency of magnetite nanoparticles (Fe3O4 NPs)/bacterial cell assembly to biodegrade lignin and lignocellulose, decontaminate pulp and paper-contaminated wastewater and optimize lignin adsorption by Fe3O4 NPs. Water samples were collected from three paper and carton manufacturing companies, Alexandria Governorate, Egypt. Pseudomonas otitidis MCC10330, the most active and promising strain among 10 previously screened indigenous and exogenous isolates, was selected and decorated with magnetic Fe3O4 Nanoparticles, that were prepared by the co-precipitation method, characterized and used to decontaminate paper and pulp effluent in a batch mode bioassay for 4 h. Fe3O4 NPs/bacterial cell assembly achieved the highest removals (64.1, 52.0, 54.3 and 66.6%) of TSS, COD, BOD, and Total Tannin and Lignin after 1, 4 and 4 h, reaching residual concentrations (RCs) of 322, 216, 112 and 7 mg/L, which are still slightly higher (5.35, 2.7 and 1.86-fold) than their maximum permissible limits (MPLs), respectively. RCs of pH, DO and TDS in the treated effluent are accepted for safe discharging. Maximum lignin adsorption and removal (82.14%) using Fe3O4 NPs was achieved at the optimized conditions (pH 6, Fe3O4 NPs dosage of 100 mg and 10 min contact time). Results confirmed that the proposed magnetite-coated Pseudomonas otitidis treatment system is highly efficient and recommended to treat the highly contaminated pulp and paper wastewater. Also, as far as we know, this integrated assemblage is the first time to be used as a novel, very promising, eco-friendly, renewable and economical biotechnological approach to minimize/eliminate the involved pollutants with the least running time. [ABSTRACT FROM AUTHOR]

Aims: Fungi species received much attention due to their numerical ability to manufacture various enzymes that can be used to break down cellulose, starch and lipids. However, the conventional way of mycelial incorporation in lignocellulolytic agriculture materials shows less quantity for the degradation of organic compounds. Therefore, fungal metabolites extract received much attention for large amounts of degradation. On the other hand, the effectiveness of fungal metabolite extracts depends on the solvent reaction process. Thus, this study compared degrading organic compounds such as lignin and cellulose in a plate assay experiment using Trichoderma reesei UMK04 secondary metabolites extract using ethyl acetate and hexene solvents. Methodology and results: The T. reesei UMK04 was cultured in potato dextrose broth (PDB) media. Secondary metabolites from the broth culture of T. reseei were extracted using two different solvents of ethyl acetate and hexene separately. The degradation of organic compounds was determined in a plate assay experiment using Jensen media and Tannic acid media. Metabolite extract of T. reesei was used in concentrations of 5 mg/mL, 10 mg/mL, 15 mg/mL and 20 mg/mL. The hollow zone method was used to determine the degradation range. The ethyl acetate solvent extract showed the highest cellulose degradation-like pigmentation formation, which appeared at 6.6 cm on the plate, compared to lignin, which was 3.6 cm. Conclusion, significance and impact of study: The secondary metabolites of T. reesei using ethyl acetate extracts showed higher cellulose degradation, which showed that solvents play the role of more effective compound extraction. [ABSTRACT FROM AUTHOR]

Ethyl levulinate (EL) is a key biomass-derived compounds due to its socio-economic benefits for the synthesis of commodity chemicals. Herein, we proposed an efficient one-step bamboo conversion to EL in ethanol, and a novel stepwise fractionation to purify EL and lignocellulose degradation products. A proton acid, due to its high catalytic efficiency, yielded 26.65 % EL in 120 min at 200 °C. The productions of ethyl glucoside and 5-ethoxymethylfurfural were analyzed in terms of by-products formation. To the best of our knowledge, there is no single report on catalyst for one step synthesis of EL directly from bamboo, as well as a stepwise fractionation to purify EL. Due to similar physiochemical properties in each fraction, the platform molecules could broaden a new paradigm of bamboo biomass utilization for renewable energy and value-added biochemicals. In addition, glucose, ethyl glucoside, corn starch, and microcrystalline cellulose were also investigated as substrates, so that the reaction intermediates of this one-pot procedure were identified and a possible reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

Wood-decaying white rot fungi live in changing environmental conditions and may switch from aerobic to fermentative metabolism under oxygen depletion. Decomposition of wood and lignocellulose by fungi is dependent on enzymatic and oxidative biochemistry including generation of reactive oxygen species. In this study, we subjected semi-solid wood-substrate cultures of the white rot fungus Phlebia radiata to oxidative stress by addition of hydrogen peroxide under aerobic and anaerobic cultivation conditions. Wood decomposition and fungal metabolism were followed by analysis of extracellular organic compounds, mycelial growth, and laccase activity. Under both atmospheric conditions, accumulation of bioactive aromatic compounds from birch wood occurred into the culture supernatants after hydrogen peroxide treatment. The supernatants inhibited both fungal growth and laccase activity. However, the fungus recovered from the oxidative stress quickly in a few days, especially when cultivated under regular aerobic conditions. With repeated hydrogen peroxide treatments, laccase suppressive-recovery effect was observed. Culture supernatants demonstrated antioxidant and antimicrobial effects, in concert with emergence of chlorinated birch-derived organic compounds. Bioactivities in the cultures disappeared in the same pace as the chlorinated compounds were transformed and de-chlorinated by the fungus. Our results indicate tolerance of white rot fungi against excessive oxidative stress and wood-derived, growth-inhibiting and harmful agents.

[Display omitted] • Inoculation of thermophilic bacterial consortia promoted the compost efficiency. • P V , n/P III , n values revealed the humification degree in different treatments. • Core microbes drove the variations in compost temperature, TOC, TN, and HAC. • Microbial community functions were closely related to compost quality. The objective of this study was to investigate the potential effects of thermophilic bacterial consortia on compost efficiency and quality. The application of bacterial consortia resulted in an earlier onset of the thermophilic period (THP), an increased upper temperature limit, and an extended duration of the THP by 3–5 days compared to the control group (CK). Microbial inoculation significantly improved the efficiency of organic matter degradation, as well as the content of water-soluble nitrogen (WSN) and humic acid-carbon (HAC). In the case of consortium Ⅱ inoculation (T2), the activities of cellobiohydrolase, β-glucosidase, and protease were increased by 81.81 %, 70.13 %, and 74.09 % at the THP respectively compared to CK. During the maturation stage, T2 also exhibited the highest P V , n/P III , n value (1.33) and HAC content (39.53 mg·g−1), indicating that inoculation of consortium Ⅱ effectively promoted substrate maturity and product quality. Moreover, this inoculation effectively optimized the bacterial communities, particularly the growth of Planococcus, Chelatococcus, and Chelativorans during the composting, which were involved in carbon and nitrogen conversion or HAC synthesis. Carbohydrate and amino acid metabolism, and membrane transport were predominant in the consortia-inoculated samples, with an increased gene abundance, suggesting that inoculation contributed to promoting the biodegradation of lignocellulose and the exchange of favorable factors. In conclusion, this study demonstrates that inoculating thermophilic bacterial consortia has a positive impact on enhancing the resource utilization efficiency of agricultural waste and improving the quality of compost products. [ABSTRACT FROM AUTHOR]

The degradation of lignocellulose in biogas processes has been focused on the inoculant microorganisms involved, with a view to gaining a deeper understanding in order to improve lignocellulose degradation. The maximum volumetric biogas yield (12.17 L/L) was achieved with the inoculum used in experiment "B", containing 400 g of digestate from the bioreactor along with 400 g of rumen fluid. The highest concentration of methane in biogas was obtained from the same inoculum composition (63.2 ± 1.5%). The second largest volumetric yield of 8.41 ± 0.45 L/L biogas was achieved in experiment "C," where digestates were used as the main inoculum. Accordingly, in this case, the volumetric yield of biogas was 8.41 ± 0.45 L/L. The composition of rumen fluid and digestate increased biogas production from the same amount of alfalfa leaves by 30.9%. [ABSTRACT FROM AUTHOR]

Composting is a sustainable alternative for green waste (GW) valorization contributing to the circular bioeconomy. However, the processing time must be reduced and the end-product quality must be improved. This study determined the effect of the incorporation of processed food waste (PFW), unprocessed food (UPFW), sawdust (SW), phosphate rock (PR) and a specific bacterial inoculum on GW-composting process parameters and product quality. Three treatments were evaluated in 120 kg piles: (i) TA: (GW + UPFW + PFW + inoculum), (ii) TB (GW + UPFW + PFW), and (iii) TC (GW). An inoculum of Bacillus sp. and Paenibacillus sp. was incorporated in the cooling phase for TA. On the other hand, the effect of the inoculum at the laboratory scale (20 kg reactors) was compared with that found at the pilot scale (120 kg piles). The incorporation of FW, SW, PR and the inoculum increased the amount of lignocellulose biodegradation (TA: 29.1%; TB: 22.7%; TC: 18.2%), which allowed for a reduction of up to 14 days of processing time. The product obtained for TA had a similar quality to the other two treatments, although a lower phytotoxicity was determined according to the germination index (TA: 95%; TB: 85%; and TC: 83%). The final product of TA showed the best agricultural characteristics with pH 8.3, TOC of 24.8%, TN of 1.32%, and GI of 98.8%. Finally, the scaling effect with the bacterial inoculum was shown to affect parameters such as the TOC, TN, GI, and, to a lesser extent, temperature and pH. The results obtained in this paper highlight the importance of optimizing the composting of GW, specifically with the use of co-substrates and specific inocula, which can be of interest for composting materials with a high content of lignocellulose such as GW. [ABSTRACT FROM AUTHOR]

[Display omitted] • Optimized organic composition boosts SSAD humification and HMs passivation. • Increasing proteins and lignocellulose enhanced HMs complexation in SSAD. • Environmental factors, especially pH, significantly influence HMs passivation. This study uncovered the impacts of feedstock organic composition, comprising proteins, lignocellulose, and lipids, on humification and passivation of heavy metals (HMs) in solid-state anaerobic digestion (SSAD). Mantel tests and partial least squares structural equation modeling (PLS-SEM) results revealed that copper (Cu) and zinc (Zn) passivation predominantly occurred through complexation with humic acid (HA). In contrast, lead (Pb) and chromium (Cr) passivation were pH-dependent as influenced by substrate conditions in SSAD. Increasing protein content in the feedstock facilitated lignocellulose biodegradation to enhance HA formation, and thus augmenting Cu and Zn passivation. Furthermore, the improved biodegradation of organic components elevated the substrate pH, further enhancing Pb and Cr passivation. Such improvement was notable when the protein: lignocellulose: lipid ratio of feedstock was regulated to 4.1:3.7:2.2, which increased HA contents to 35.25% and pH to 9 to enhance the passivation of Cu, Pb, and Cr by 0.48%, 52.0%, and 17.9%, respectively. [ABSTRACT FROM AUTHOR]

The essential oil from Melaleuca leucadendra L. leaves has been widely used as a perfume and traditional remedy, cosmetics and pharmaceutical products ingredient since many years ago. The common technology to recover the oil is hydro-distillation and steam-distillation. However, all oil can not be fully extracted from the leaves by this method due to the recalcitrant structure of leaves that hindrance the access of the solvent. Adding a submerged fermentation as a pre-treatment step prior to the extraction process helped to loosen the lignocellulose structure and enhance oil release in the extraction process. In this study, the raw materials were collected from the natural forest in Buru Island, Maluku, Indonesia. The biological agents applied in these processes were Phanerochaete chrysosporium ITBCC136 and Trichoderma viride ITBCC143. The oil extraction process was conducted by method of steam-distillation, the oil was analysed using gas chromatography-mass spectroscopy (GC-MS), and the lignocellulose content in the biomass was measured by the fractionation method. The treatment using T.viride provided the highest increase in yield percentage up to 3.47% as compared with control of 1.45%, with the lowest percentages of the remained cellulose, while the fermentation with the presence of P.chrysosporium did not affect the oil yield even the lignin content was decrease as much as 21%. The percentages of 1,8-cineole in the oil were almost unchanged, which was about 20% of the oil.

Anaerobic fungus–methanogen co-cultures from rumen liquids and faeces can degrade lignocellulose efficiently. In this study, 31 fungus–methanogen co-cultures were first obtained from the rumen of yaks grazing in Qinghai Province, China, using the Hungate roll-tube technique. The fungi were identified according to morphological characteristics and internal transcribed spacer (ITS) sequences. The methanogens associated with each fungus were identified by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and 16S rRNA gene sequencing. They were five co-culture types: Neocallimastix frontalis + Methanobrevibacter ruminantium, Neocallimastix frontalis + Methanobrevibacter gottschalkii, Orpinomyces joyonii + Methanobrevibacter ruminantium, Caecomyces communis + Methanobrevibacter ruminantium, and Caecomyces communis + Methanobrevibacter millerae. Among the 31 co-cultures, during the 5-day incubation, the N. frontalis + M. gottschalkii co-culture YakQH5 degraded 59.0%–68.1% of the dry matter (DM) and 49.5%–59.7% of the neutral detergent fiber (NDF) of wheat straw, corn stalk, rice straw, oat straw and sorghum straw to produce CH4 (3.0–4.6 mmol/g DM) and acetate (7.3–8.6 mmol/g DM) as end-products. Ferulic acid (FA) released at 4.8 mg/g DM on corn stalk and p-coumaric acid (PCA) released at 11.7 mg/g DM on sorghum straw showed the highest values, with the following peak values of enzyme activities: xylanase at 12,910 mU/mL on wheat straw, ferulic acid esterase (FAE) at 10.5 mU/mL on corn stalk, and p-coumaric acid esterase (CAE) at 20.5 mU/mL on sorghum straw. The N. frontalis + M. gottschalkii co-culture YakQH5 from Qinghai yaks represents a new efficient combination for lignocellulose biodegradation, performing better than previously reported fungus–methanogen co-cultures from the digestive tract of ruminants. [ABSTRACT FROM AUTHOR]

Lignocellulose biomass (LCB) has extensive applications in many fields such as bioenergy, food, medicines, and raw materials for producing value‐added products. One of the keys to efficient utilization of LCB is to obtain directly available oligo‐ and monomers (e. g. glucose). With the characteristics of easy recovery and separation, high efficiency, economy, and environmental protection, immobilized enzymes have been developed as heterogeneous catalysts to degrade LCB effectively. In this review, applications and mechanisms of LCB‐degrading enzymes are discussed, and the nanomaterials and methods used to immobilize enzymes are also discussed. Finally, the research progress of lignocellulose biodegradation catalyzed by nano‐enzymes was discussed. [ABSTRACT FROM AUTHOR]

In the Anthropocene, plastic pollution is a worldwide concern that must be tackled from different viewpoints, bringing together different areas of science. Microbial transformation of polymers is a broad-spectrum research topic that has become a keystone in the circular economy of fossil-based and biobased plastics. To have an open discussion about these themes, experts in the synthesis of polymers and biodegradation of lignocellulose and plastics convened within the framework of The Transnational Network for Research and Innovation in Microbial Biodiversity, Enzymes Technology and Polymer Science (MENZYPOL-NET), which was recently created by early-stage scientists from Colombia and Germany. In this context, the international workshop "Microbial Synthesis and Degradation of Polymers: Toward a Sustainable Bioeconomy" was held on 27 September 2021 via Zoom. The workshop was divided into two sections, and questions were raised for discussion with panelists and expert guests. Several key points and relevant perspectives were delivered, mainly related to (i) the microbial evolution driven by plastic pollution; (ii) the relevance of and interplay between polymer structure/composition, enzymatic mechanisms, and assessment methods in plastic biodegradation; (iii) the recycling and valorization of plastic waste; (iv) engineered plastic-degrading enzymes; (v) the impact of (micro)plastics on environmental microbiomes; (vi) the isolation of plastic-degrading (PD) microbes and design of PD microbial consortia; and (vii) the synthesis and applications of biobased plastics. Finally, research priorities from these key points were identified within the microbial, enzyme, and polymer sciences. [ABSTRACT FROM AUTHOR]

Microorganisms play a vital role in the degradation of organic matters such as Sawdust and woodchips. In this study, the Serial dilution method and pour plate techniques were used according to microbiological standards. The media used were nutrient agar, sabouraud dextrose agar, and cellulolytic medium to identify microorganisms and inoculated them into the Sawdust and woodchips and kept for 30 days at 37 oC and 25 oC. The total viable bacterial count for Sawdust and woodchips ranged between 9.0×103 - 6.0×103and 1.96×103 - 1.48×103, respectively. A total of 12 organisms were identified according to the biochemical reactions, six bacteria, and six fungi. Bergy's manual of determinative bacteriology confirmed the organism as Escherichia coli, Pseudomonas aeruginosa, Klebsiella sp, Staphylococcus aureus, Bacillus cereus, and Cellulomona sp. The fungal species identified include Rhizopus sp, Mucor sp, Saccharomyces cerevisiae, Candida sp, Aspergillus niger, and Aspergillus flavus. The bacteria with the highest potential to degrade Sawdust and Woodchips are Cellulomonas sp. (20.9%), Klebsiella sp (17.8%), Escherichia coli (8.3%), Bacillus cereus (7.15%), and Staphylococcus sp (6.2%). Furthermore, the fungi capable of degrading the Sawdust and woodchips are Mucor sp (19.90%), Aspergillus flavus (17.8%), Aspergillus niger (17.3%), Rhizopus (16.9%), and Saccharomyces cerevisiae (15.55%). From these results, it can be concluded that some microorganisms could be used for the biodegradation of lignocellulose materials. [ABSTRACT FROM AUTHOR]

Xyloglucan is closely associated with cellulose and still retained with some modification in pretreated lignocellulose; however, its influence on lignocellulose biodegradation is less understood. TtGH74 from Thielavia terrestris displayed much higher catalytic activity than previously characterized fungal GH74 xyloglucanases. The carbohydrate-binding module 1 (CBM1) deleted variant (TtGH74ΔCBM) had the same optimum temperature and pH but an elevated thermostability. TtGH74 displayed a high binding affinity on xyloglucan and cellulose, while TtGH74ΔCBM completely lost the adsorption capability on cellulose. Their hydrolysis action alone or in combination with other glycoside hydrolases on the free xyloglucan, xyloglucan-coated phosphoric acid-swollen cellulose or pretreated corn bran and apple pomace was compared. CBM1 might not be essential for the hydrolysis of free xyloglucan but still effective for the associated xyloglucan to an extent. TtGH74 alone or synergistically acting with the CBH1/EG1 mixture was more effective in the hydrolysis of xyloglucan in corn bran, while TtGH74ΔCBM showed relatively higher catalytic activity on apple pomace, indicating that the role and significance of CBM1 are substrate-specific. The degrees of synergy for TtGH74 or TtGH74ΔCBM with the CBH1/EG1 mixture reached 1.22–2.02. The addition of GH10 xylanase in TtGH74 or the TtGH74ΔCBM/CBH1/EG1 mixture further improved the overall hydrolysis efficiency, and the degrees of synergy were up to 1.50–2.16. [ABSTRACT FROM AUTHOR]

Wood-decaying white rot fungi live in changing environmental conditions and may switch from aerobic to fermentative metabolism under oxygen depletion. Decomposition of wood and lignocellulose by fungi is dependent on enzymatic and oxidative biochemistry including generation of reactive oxygen species. In this study, we subjected semi-solid wood-substrate cultures of the white rot fungus Phlebia radiata to oxidative stress by addition of hydrogen peroxide under aerobic and anaerobic cultivation conditions. Wood decomposition and fungal metabolism were followed by analysis of extracellular organic compounds, mycelial growth, and laccase activity. Under both atmospheric conditions, accumulation of bioactive aromatic compounds from birch wood occurred into the culture supernatants after hydrogen peroxide treatment. The supernatants inhibited both fungal growth and laccase activity. However, the fungus recovered from the oxidative stress quickly in a few days, especially when cultivated under regular aerobic conditions. With repeated hydrogen peroxide treatments, laccase suppressive-recovery effect was observed. Culture supernatants demonstrated antioxidant and antimicrobial effects, in concert with emergence of chlorinated birch-derived organic compounds. Bioactivities in the cultures disappeared in the same pace as the chlorinated compounds were transformed and de-chlorinated by the fungus. Our results indicate tolerance of white rot fungi against excessive oxidative stress and wood-derived, growth-inhibiting and harmful agents., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Lignocellulosic biomass such as agricultural and forestry waste is the most abundant renewable organic carbon source on earth and can be used to produce source of clean energy such as ethanol. One of the disadvantages of the preparation of ethanol using lignocellulose as raw material is the high cost of production of cellulase. Fungi are capable of effectively degrading lignocellulose and secreting a large amount of cellulase, and have the advantages of ease of preparation, high yield, and full enzyme systems. Therefore, this paper reviews sources of lignocellulose and the biodegradation properties which limit the production of cellulase, proposes micro-organisms capable of degrading lignocellulose and explains the types of cellulase, and the mechanism of action, methods of fermentation optimization, and control are analyzed, and ways to increase the yield of cellulase are described. Finally, research on the effects of inducers on the production of cellulase by fungi is reviewed. The aims of this review are to provide a reference for the efficient production and industrial application of cellulase. [ABSTRACT FROM AUTHOR]

The essential oil from Melaleuca leucadendra L. leaves has been widely used as a perfume and traditional remedy, cosmetics and pharmaceutical products ingredient since many years ago. The common technology to recover the oil is hydro-distillation and steam-distillation. However, all oil can not be fully extracted from the leaves by this method due to the recalcitrant structure of leaves that hindrance the access of the solvent. Adding a submerged fermentation as a pretreatment step prior to the extraction process helped to loosen the lignocellulose structure and enhance oil release in the extraction process. In this study, the raw materials were collected from the natural forest in Buru Island, Maluku, Indonesia. The biological agents applied in these processes were Phanerochaete chrysosporium ITBCC136 and Trichoderma viride ITBCC143. The oil extraction process was conducted by method of steam-distillation, the oil was analysed using gas chromatography-mass spectroscopy (GC-MS), and the lignocellulose content in the biomass was measured by the fractionation method. The treatment using T.viride provided the highest increase in yield percentage up to 3.47% as compared with control of 1.45%, with the lowest percentages of the remained cellulose, while the fermentation with the presence of P.chrysosporium did not affect the oil yield even the lignin content was decrease as much as 21%. The percentages of 1,8-cineole in the oil were almost unchanged, which was about 20% of the oil. [ABSTRACT FROM AUTHOR]

Lignocellulosic materials have a complex physicochemical composition and structure that reduces their decomposition rate and hinders the formation of humic substances during composting. Therefore, a composting experiment was conducted to evaluate the effects of different C/N ratios on lignocellulose (cellulose, hemicellulose and lignin) degradation and the activities of corresponding enzymes during aerobic composting. The study had five C/N ratios, namely, T1 (C/N ratio of 15), T2 (C/N ratio of 20), T3 (C/N ratio of 25), T4 (C/N ratio of 30) and T5 (C/N ratio of 35). The results showed that treatments T3 and T4 had the highest rate of degradation of cellulose and hemicellulose, while treatment T3 had the highest rate of degradation of lignin. Among the five treatments, treatment T3 enhanced the degradation of the lignocellulose constituents, indicating a degradation rate of 6.86–35.17%, 15.63–44.08% and 31.69–165.60% for cellulose, hemicellulose and lignin, respectively. The degradation of cellulose and lignin occurred mainly at the thermophilic and late mesophilic phases of composting, while hemicellulose degradation occurred at the maturation phase. Treatment T3 was the best C/N ratio to stimulate the activities of manganese peroxidase, lignin peroxidase, polyphenol oxidase and peroxidase, which in turn promoted lignocellulose degradation. [ABSTRACT FROM AUTHOR]

Fungi are ecologically outstanding decomposers of lignocellulose. Fungal lignocellulose degradation is prominent in saprotrophic Ascomycota and Basidiomycota of the subkingdom Dikarya. Despite ascomycetes dominating the Dikarya inventory of aquatic environments, genome and transcriptome data relating to enzymes involved in lignocellulose decay remain limited to terrestrial representatives of these phyla. We sequenced the genome of an exclusively aquatic ascomycete (the aquatic hyphomycete Clavariopsis aquatica), documented the presence of genes for the modification of lignocellulose and its constituents, and compared differential gene expression between C. aquatica cultivated on lignocellulosic and sugar-rich substrates. We identified potential peroxidases, laccases, and cytochrome P450 monooxygenases, several of which were differentially expressed when experimentally grown on different substrates. Additionally, we found indications for the regulation of pathways for cellulose and hemicellulose degradation. Our results suggest that C. aquatica is able to modify lignin to some extent, detoxify aromatic lignin constituents, or both. Such characteristics would be expected to facilitate the use of carbohydrate components of lignocellulose as carbon and energy sources. [ABSTRACT FROM AUTHOR]

Abstract Background For enzymes with buried active sites, transporting substrates/products ligands between active sites and bulk solvent via access tunnels is a key step in the catalytic cycle of these enzymes. Thus, tunnel engineering is becoming a powerful strategy to refine the catalytic properties of these enzymes. The tunnel-like structures have been described in enzymes catalyzing bulky substrates like glycosyl hydrolases, while it is still uncertain whether these structures involved in ligands exchange. Till so far, no studies have been reported on the application of tunnel engineering strategy for optimizing properties of enzymes catalyzing biopolymers. Results In this study, xylanase S7-xyl (PDB: 2UWF) with a deep active cleft was chosen as a study model to evaluate the functionalities of tunnel-like structures on the properties of biopolymer-degrading enzymes. Three tunnel-like structures in S7-xyl were identified and simultaneously reshaped through multi-sites saturated mutagenesis; the most advantageous mutant 254RL1 (V207N/Q238S/W241R) exhibited 340% increase in specific activity compared to S7-xyl. Deconvolution analysis revealed that all three mutations contributed synergistically to the improved activity of 254RL1. Enzymatic characterization showed that larger end products were released in 254RL1, while substrate binding and structural stability were not changed. Dissection of the structural alterations revealed that both the tun_1 and tun_2 in 254RL1 have larger bottleneck radius and shorter length than those of S7-xyl, suggesting that these tunnel-like structures may function as products transportation pathways. Attributed to the improved catalytic efficiency, 254RL1 represents a superior accessory enzyme to enhance the hydrolysis efficiency of cellulase towards different pretreated lignocellulose materials. In addition, tunnel engineering strategy was also successfully applied to improve the catalytic activities of three other xylanases including xylanase NG27-xyl from Bacillus sp. strain NG-27, TSAA1-xyl from Geobacillus sp. TSAA1 and N165-xyl from Bacillus sp. N16-5, with 80%, 20% and 170% increase in specific activity, respectively. Conclusions This study represents a pilot study of engineering and functional verification of tunnel-like structures in enzymes catalyzing biopolymer. The specific activities of four xylanases with buried active sites were successfully improved by tunnel engineering. It is highly likely that tunnel reshaping can be used to engineer better biomass-degrading abilities in other lignocellulolytic enzymes with buried active sites.

Penicillium purpurogenum is a filamentous fungus, which grows on a variety of natural carbon sources and secretes a large number of enzymes involved in cellulose, hemicelluloses and pectin biodegradation. The purpose of this work has been to identify potential lignocellulolytic enzymes and to compare the secreted enzymes produced when the fungus is grown on sugar beet pulp (rich in cellulose and pectin) and corn cob (rich in cellulose and xylan). Culture supernatants were subjected to two-dimensional nano-liquid chromatography/tandem mass spectrometry. Using MASCOT and a genome-derived protein database, the proteins present in the supernatant were identified. The putative function in the degradation of the polysaccharides was determined using dbCAN software. The results show that there is a good correlation between the polysaccharide composition of the carbon sources and the function of the secreted enzymes: both cultures are rich in cellulases, while sugar beet pulp induces pectinases and corncob, xylanases. The eventual biochemical characterisation of these enzymes will be of value for a better understanding of the biodegradation process performed by the fungus and increase the availability of enzymes for biotechnological methods associated with this process.

Bacterial systems have gained wide attention for depolymerization of lignocellulosic biomass, due to their high functional diversity and adaptability. To achieve the full microbial exploitation of lignocellulosic residues and the cost-effective production of bioproducts within a biorefinery, multiple metabolic pathways and enzymes of various specificities are required. In this work, highly diverse aerobic, mesophilic bacteria enriched from Keri Lake, a pristine marsh of increased biomass degradation and natural underground oil leaks, were explored for their metabolic versatility and enzymatic potential towards lignocellulosic substrates. A high number of Pseudomonas species, obtained from enrichment cultures where organosolv lignin served as the sole carbon and energy source, were able to assimilate a range of lignin-associated aromatic compounds. Comparatively more complex bacterial consortia, including members of Actinobacteria, Proteobacteria, Bacilli, Sphingobacteria, and Flavobacteria, were also enriched from cultures with xylan or carboxymethyl cellulose as sole carbon sources. Numerous individual isolates could target diverse structural lignocellulose polysaccharides by expressing hydrolytic activities on crystalline or amorphous cellulose and xylan. Specific isolates showed increased potential for growth in lignin hydrolysates prepared from alkali pretreated agricultural wastes. The results suggest that Keri isolates represent a pool of effective lignocellulose degraders with significant potential for industrial applications in a lignocellulose biorefinery.

The postindustrial era is currently facing two ecological challenges. First, the rise in global temperature, mostly caused by the accumulation of carbon dioxide (CO2) in the atmosphere, and second, the inability of the environment to absorb the waste of human activities. Fungi are valuable levers for both a reduction in CO2 emissions, and the improvement of a circular economy with the optimized valorization of plant waste and biomass. Soil fungi may promote plant growth and thereby increase CO2 assimilation via photosynthesis or, conversely, they may prompt the decomposition of dead organic matter, and thereby contribute to CO2 emissions. The strategies that fungi use to cope with plant-cell-wall polymers and access the saccharides that they use as a carbon source largely rely on the secretion of carbohydrate-active enzymes (CAZymes). In the past few years, comparative genomics and phylogenomics coupled with the functional characterization of CAZymes significantly improved the understanding of their evolution in fungal genomes, providing a framework for the design of nature-inspired enzymatic catalysts. Here, we provide an overview of the diversity of CAZyme enzymatic systems employed by fungi that exhibit different substrate preferences, different ecologies, or belong to different taxonomical groups for lignocellulose degradation. [ABSTRACT FROM AUTHOR]

The recently identified lytic polysaccharide monooxygenases (LPMOs) are important auxiliary proteins which contribute to lignocellulose biodegradation by oxidatively cleaving the glycosidic bonds in cellulose and other polysaccharides. The vast differences in terms of substrate specificity and regioselectivity within LPMOs provide us new possibilities to find promising candidates for the use in enzyme cocktails in biorefinery applications. In this study, a highly xyloglucan active family AA9 lytic polysaccharide monooxygenase Ep LPMO9A was identified from Eupenicillium parvum 4-14. Ep LPMO9A exhibited a mixed C1/C4 oxidative cleavage activity on cellulose and xyloglucan with a broad range of pH stability and good thermal stability at 40 °C. It showed a higher boosting effect on the enzymatic saccharification of complex lignocellulosic substrates associated with xyloglucan than on the lignocellulosic substrates without xyloglucan particularly in low commercial cellulase dosage cases. The oxidative cleavage of xyloglucan by Ep LPMO9A may facilitate to open up the sterical hindrance of cellulose by xyloglucan and thereby increase accessibility for cellulase to lignocellulosic substrates. The discovery of more and more hemicellulose-active LPMOs and their contribution to breaking down the barriers by oxidatively acting on hemicellulose may expand our knowledge for their functions of LPMOs in lignocellulose biodegradation. [ABSTRACT FROM AUTHOR]

The capacity of Pleurotus ostreatus to degrade the lignocellulose of spent coffee grounds (SCG) and its resultant nutrient composition is not yet studied. The study tested four SCG/wheat straw mixtures, containing 0, 33, 67, or 100% SCG. Initial lignin content was higher, and lignin loss was lower in mixtures containing SCG, compared to control revealing lower substrate degradation. Biological yield was negatively correlated with initial lignin content, and positively with the lignin loss from substrates. The nutritional value of mushrooms was improved by a general increase in carbohydrates, a decrease in sodium content with 33% and 67% SCG, and lower fat content with 33% SCG. Polyunsaturated fatty acids of mushrooms (PUFA) increased with 67% SCG; while saturated ones (SFA) increased with 33 and 67% SCG. All mushrooms had a close PUFA/SFA, ranging between 7.4 and 8.1. The study suggests using SCG as a nutritional supplement to the commercial wheat straw. [ABSTRACT FROM AUTHOR]

Aims: Lytic polysaccharide monooxygenase (LPMO) is an enzyme capable of cleaving glycoside bonds of recalcitrant polysaccharides through an oxidative mechanism. LPMO activity, in synergy with hydrolytic enzymes, increases the production of monomer sugars from the biodegradation of lignocellulose. This study was aimed at evaluating actinomycete S2 strain LPMO activity based on the release of xylose as one of reducing sugar and hydrogen peroxide (H2O2) in the course of lignocellulosic biodegradation. Methodology and results: The oxidation activity of LPMO from actinomycete S2 strain was measured by using the substrate of Avicel supplemented with ascorbic acid and copper ions (Cu2+) to identify its effect on the release of xylose as one of reducing sugar. The optimum incubation time for the LPMO production was also conducted. Further, H2O2 quantitative analysis was performed as by-product of LPMO activity and 16S rRNA gene sequence of actinomycete S2 strain were subsequently determined. We found that supplementation of 1 mM ascorbic acid and 0.2 mM Cu2+ increased xylose as one of reducing sugar production by up to 5-fold from 255.03 to 1290 μg/mL after an optimal incubation period of 6 days. Based on H2O2 production, the LPMO activity of actinomycete S2 strain was 0.019 ± 0.001 U/mL. There is likelihood that LPMO activity derived from actinomycete S2 strain has a synergistic effect with the activity of other lignocellulose-degrading enzymes. This actinomycete showed 99% similarity to the 16S rRNA gene sequence of Streptomyces avermitilis strain EAAG80. Conclusion, significance, and impact of study: LPMO enzyme activity from actinomycete S2 strain as determined by the production of reducing sugar and H2O2was greatly increased by supplementation with ascorbic acid as an electron donor and Cu2+ ions. To the best of our knowledge, this is the first elucidation of LPMO activity from an indigenous Indonesian actinomycete. [ABSTRACT FROM AUTHOR]

The high lignocellulolytic activity displayed by the soft-rot fungus Penicillium purpurogenum has made it a target for the study of novel lignocellulolytic enzymes. We have obtained a reference genome of 36.2 Mb of non-redundant sequence (11,057 protein-coding genes). The 49 largest scaffolds cover 90% of the assembly, and Core Eukaryotic Genes Mapping Approach (CEGMA) analysis reveals that our assembly captures almost all protein-coding genes. RNA-seq was performed and 93.1% of the reads aligned to the assembled genome. These data, plus the independent sequencing of a set of genes of lignocellulose-degrading enzymes, validate the quality of the genome sequence. P. purpurogenum shows a higher number of proteins with CAZy motifs, transcription factors and transporters as compared to other sequenced Penicillia. These results demonstrate the great potential for lignocellulolytic activity of this fungus and the possible use of its enzymes in related industrial applications.

Lignocellulosic materials are the constituent elements of all plants and are most renewable feedstock available for most regions of our world. Lignocellulosic waste represents huge amounts of unutilized plant-based bioresurces, difficult to degrade for industry. Very important components of natural lignocellulosic materials are carbohydrate polymers represented by cellulose and hemicellulose, and lignin an aromatic polymer. In its natural lignocellulose state, cellulose is protected from microbial degradation, mainly due to the lignin and hemicellulose polymer components. The biotechnology of lignocellulosic material conversion into bio-products normally requires multistep processes. The focus of this article is a study on the potential cultivation of edible and medicinal mushrooms, using different types of residues as natural substrates: fruit tree wastes, winery and vine wastes, agricultural and agro-industrial wastes. A large number of fungi are capable for selectively degrading lignin. Proper management of lignocellulose biodegradation and utilization can serve to improve the quality of the environment. [ABSTRACT FROM AUTHOR]

Industrial processes lead to high amounts of lignocellulosic wastes, that are not valorised properly. Feruloyl esterase are a group of accesory enzymes used in the biodegradation of lignocellulose, capable of releasing ferulic acid that is located either between lignin and hemicellulose or between hemicelluloses. The importance of feruloyl esterase is given mainly by the fact that its action allows other enzymes to hydrolyse xylan or lignin. The released ferulic acid has several applicatios in various industries such as food, feed, medical, biofuel, pulp and paper etc. Feruloyl esterases are produced by several microorganisms (bacteria or fungi), but research studies are still focused on finding more sources for these enzymes. There are different methods for detecting microbial strains able to produce feruloyl esterase, the most used being plate screening methods. [ABSTRACT FROM AUTHOR]

Lignocellulose is an important component of domestic biodegradable waste (DBW), and its complex structure makes it an obstacle in the biological treatment of DBW. Here, we identify black soldier fly larvae (Hermetia illucens L., BSFL) as a bioreactor for lignocellulose degradation in DBW based on their ability to effectively recruit lignocellulose-degrading bacteria. This study mainly examined the lignocellulose degradation, dynamic succession of the microbial community, gene expression of carbohydrate-active enzymes (CAZymes), and co-occurrence network analysis. Investigation of lignocellulose degradation by BSFL within 14 days indicated that the lignocellulose biodegradation rate in the larvae treatment (LT, 26.5%) group was higher than in natural composting (NC, 4.06%). In order to gain a more comprehensive understanding of microbiota, we conducted metagenomic sequencing of larvae intestines (LI), along with the LT and NC. The relative abundance of lignocellulose-degrading bacteria and CAZymes genes in LT and LI were higher than those in NC based on metagenomics sequencing. Importantly, genes coding cellulase and hemicellulase in LI were 3.36- and 2.79-fold higher, respectively, than that in LT, while the ligninase genes in LT were 1.82-fold higher than in LI. A co-occurrence network analysis identified Enterocluster and Luteimonas as keystone taxa in larvae intestines and residues, respectively, with a synergistic relationship to lignocellulose-degrading bacteria. The mechanism of recruiting functional bacteria through the larvae intestines promoted lignocellulose degradation in DBW, improving the efficiency of BSFL biotechnology and resource regeneration. [Display omitted] • BSFL recruited lignocellulose degrading functional bacteria in gut-residue system. • BSFL enriched with functional bacteria improved lignocellulose degradation by 526%. • Corynebacterium and Brevibacterium recruited mainly in residues to degrade lignin. • Dysgonomonas, Prevotella, and Miniimonas recruited in gut to degrade celluloses. • Enterocluster and Luteimonas as keystone taxa in BSFL intestines and residues. [ABSTRACT FROM AUTHOR]

Penicillium purpurogenum is a filamentous fungus, which grows on a variety of natural carbon sources and secretes a large number of enzymes involved in cellulose, hemicelluloses and pectin biodegradation. The purpose of this work has been to identify potential lignocellulolytic enzymes and to compare the secreted enzymes produced when the fungus is grown on sugar beet pulp (rich in cellulose and pectin) and corn cob (rich in cellulose and xylan). Culture supernatants were subjected to two-dimensional nano-liquid chromatography/tandem mass spectrometry. Using MASCOT and a genome-derived protein database, the proteins present in the supernatant were identified. The putative function in the degradation of the polysaccharides was determined using dbCAN software. The results show that there is a good correlation between the polysaccharide composition of the carbon sources and the function of the secreted enzymes: both cultures are rich in cellulases, while sugar beet pulp induces pectinases and corncob, xylanases. The eventual biochemical characterisation of these enzymes will be of value for a better understanding of the biodegradation process performed by the fungus and increase the availability of enzymes for biotechnological methods associated with this process. [ABSTRACT FROM AUTHOR]

Termites are global pests and can cause serious damage to buildings, crops, and plantation forests. The symbiotic intestinal flora plays an important role in the digestion of cellulose and nitrogen in the life of termites. Termites and their symbiotic microbes in the gut form a synergistic system. These organism work together to digest lignocellulose to make the termites grow on nitrogen deficient food. In this paper, the diversity of symbiotic microorganisms in the gut of termites, including protozoan, spirochetes, actinomycetes, fungus and bacteria, and their role in the digestion of lignocellulose and also the biotechnological applications of these symbiotic microorganisms are discussed. The high efficiency lignocellulose degradation systems of symbiotic microbes in termite gut not only provided a new way of biological energy development, but also has immense prospect in the application of cellulase enzymes. In addition, the study on the symbiotic microorganisms in the gut of termites will also provide a new method for the biological control of termites by the endophytic bacteria in the gut of termites. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Cellulose is converted to glucose in yield of 83% by WCl 6 in [BMIM]Cl at 70 °C. • Nature cellulose and lignocelluloses can be degraded by WCl 6 in high yield of TRS. • WCl6 can interact with aldehyde O in cellulose to break the 1,4-glucosidic bond. Abstract Degradation of cellulose to reducing sugar is the key step for the conversion of cellulose to valuable chemicals. Cellulose was degraded by WCl 6 in 1-butyl-3-methyl imidazole chloride at 80 °C and lower. 83% and 85.5% yield of total reducing sugar was gotten at 70 and 80 °C, respectively. Compared with inorganic acid, heteropoly acid, acidic ionic liquid and other metal chlorides, WCl 6 has shown better catalytic performance for degradation of cellulose to reducing sugar. The effect of reaction temperature, reaction time, WCl 6 amount and cellulose concentration were investigated. Degradation of cellulose by WCl 6 in 1-butyl-3-methyl imidazole chloride is a zero reaction. WCl 6 also showed excellent catalytic performance for the degradation of nature cellulose and lignocellulose. Catalyst can be reused at least 5 times without decrease of reducing sugar yield. The mechanism of degradation of WCl 6 was also suggested. [ABSTRACT FROM AUTHOR]

Present study aimed to evaluate the vermicomposting of lignocellulosic wastes employing Eisenia fetida earthworms. The study examined the effectiveness of vermicomposting for 105 days by mixing lignocellulosic waste (LW) with cattle manure (CM) in five different proportions. Results revealed that TOC and C/N ratio decreased gradually till end and in vermicomposts varied between 268–320 g/kg and 12.26–16.85, respectively. Nutrient content (NPK) in the vermicomposts increased with time in all the mixtures. Heavy metals' content also increased in vermicomposts and benefit ratio for heavy metals ranged between 0.06 and 5.1. Increase in earthworm biomass (22.38–39.64 g) and reproduction (21.27–31.60 hatchlings/worm) was also satisfactory in all the waste mixtures. Based on results, it can be inferred that lignocellulosic waste can successfully be converted into good quality manure employing earthworms. [ABSTRACT FROM AUTHOR]

The thermophilic fungus Thielavia terrestris when cultured on cellulose produces a cocktail of thermal hydrolases with potential application in saccharification of lignocellulosic biomass and other biotechnological areas. Glucuronoyl esterases are considered to play a unique role as accessory enzymes in lignocellulosic material biodegradation by cleaving the covalent ester linkage between 4-O-methyl-D-glucuronic acid (MeGlcA) and lignin in lignin-carbohydrate complexes (LCCs). Two glucuronoyl esterases from T. terrestris named TtGE1 and TtGE2 were expressed in Pichia pastoris. Both esterases displayed features of thermophilic enzymes, with the optimal temperature at 45 °C and 55 °C. TtGE1 and TtGE2 exhibited activity towards methyl (4-nitrophenyl β-D-glucopyranosid) uronate (Me-GlcA-pNP) but no catalytic activity to benzyl-D-glucuronate (BnzGlcA), indicating the difference in substrate specificity from previously studied fungal GEs. A substantial increase in the release of monomeric sugars and glucuronic acid from autohydrolysis of corn bran was observed by the supplementing TtGEs into commercial xylanase; the results clearly demonstrated that the TtGEs played a significant role in this degradation process. This research on TtGEs enriches our knowledge of this novel class of fungal GEs. These newly characterized TtGEs could be used as promising accessory enzymes to improve the hydrolysis efficiency of commercial enzymes in saccharification of lignocellulosic materials due to their thermophilic characteristics. [ABSTRACT FROM AUTHOR]

Abstract The effect and the response of several trace elements (TE) addition to the anaerobic degradation of key compounds of lignocellulosic biomass were evaluated. Lignin, cellulose and xylose were selected as principal compounds of lignocellulosic biomass. Lignin degradation was only improved by the addition of 1000 mg Fe/L, which allowed an improvement on the methane yield coefficient of 28% compared to control. SEM images from an abiotic assay showed that this effect is more likely related with a chemical effect induced by the Fe solution, instead of an enzymatic response. Pre-treatments focused on breaking the recalcitrant structure of the lignin could be more promising than TE addition for rich lignin-content substrates. Unlike to the response observed with lignin, cellulose showed a clear effect of the TE addition on methane production rate, indicating a higher preponderance of the enzymatic activity compared to the lignin biomethanization. Experiments with xylose resulted in a strong accumulation of volatile fatty acids. TE addition should be adapted to the substrate composition given the different response of each lignocellulosic compound to the different TE addition. Highlights • Lignin, cellulose and xylose were selected to represent the lignocellulose biomass. • Trace elements addition affected differently the biomethanization of each compound. • The addition of 1000 mg Fe/L had an abiotic effect on the structure of the lignin. • Biomethanization of cellulose was significantly affected by Mn addition. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A novel biotechnology combined Fe 3 O 4 NMs and fungal treatment was proposed. • Possible mechanism of enhanced Fenton process was discussed. • Interaction between Fe 3 O 4 NMs and microorganisms was illustrated. • Decrystallization of lignocellulose by fungal treatment was observed. Abstract Nowadays, Nano-biotechnology is emerging to be one of the most promising tools in environmental remediation. In this study, the degradation efficiency of lignocellulose by white-rot fungi was improved by addition of Fe 3 O 4 nanomaterials (NMs) in solid-state fermentation. The highly-ordered cellulose crystalline was demonstrated to be broken down through infrared spectroscopy (FT-IR) and crystallinity index analysis. The decay of fluorescence intensity presented a lower degree of aromatic polycondensation and less conjugated chromophores in lignocellulose. Mechanistic analysis showed that NMs participated in the Fenton reaction and affected lignocellulose biodegradation process by regulating enzyme secretion. Specifically, the time variation curves of hydroxyl radicals and Fe2+ were discussed to illustrate the degradation pattern. The NMs remained stable after the fermentation and were possible to be recycled for the next cycle. All the results support that the synergism of Fe 3 O 4 NMs and white-rot fungi would be a promising research direction in lignocellulose treatment. [ABSTRACT FROM AUTHOR]

Cassava starch factory residue (CSFR) is an attractive lignocellulosic material for bioethanol production because it is one of the most abundant renewable resources. The purpose of this work was to investigate the technical feasibility of converting CSFR into fermentable sugars using 12 different pretreatment methods. The yields of monosaccharides, oligosaccharides, and total sugars present in the hydrolysates obtained from the different pretreatment methods were examined by transferring the solid organic matter present to a liquid phase. We found that pretreatment with a dilute acid was superior to both alkaline and hot water pretreatment methods, while combined chemical‐enzymatic pretreatment was superior to single enzymatic pretreatment. More specifically, treatment with a dilute acid was conducive to the formation of monomeric sugars, whereas single enzyme pretreatment and high‐temperature alkaline pretreatment methods were conducive to the formation of oligomeric sugars. Pretreatment with 0.5% (w/v) HNO3 (160 °C, 10 min) gave the highest total monosaccharide concentration (i.e., 25,827 mg/L) with a yield of 30.99%, whereas hemicellulose (45 U/g CSFR) + cellulose (120 U/g CSFR) pretreatment gave the highest total oligosaccharide concentration (i.e., 22,152 mg/L) with a yield of 26.69%. Finally, pretreatment with 1% (w/v) H2SO4 (121 °C, 40 min) + hemicellulose (120 U/g CSFR) + cellulose (120 U/g CSFR) gave the highest total sugar concentration (i.e., 43,196 mg/L) with a yield of 51.84%. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 624–629, 2019 [ABSTRACT FROM AUTHOR]

Abstract Symbionts in the gut of termites are expected to be large sources of enzymes involved in lignocellulose degradation, but their biotechnological potential has not been fully explored. In this study, we expressed, purified, and biochemically characterized a glycoside hydrolase family 11 xylanase, NtSymX11, from a symbiotic bacterium of the higher termite, Nasutitermes takasagoensis. NtSymX11 is a multimodular enzyme consisting of a catalytic domain and two tandem carbohydrate-binding modules (CBM36). The pH and temperature optima of NtSymX11 were pH 6.0 and 40 °C, respectively. By comparing the properties of full-length and truncated variants of NtSymX11, it was shown that CBM36 decreases the enzyme stability at acidic pH and high temperature. The main products from xylohexaose and various xylan substrates were X1-X3 xylooligosaccharides. Analysis of kinetic parameters indicated that NtSymX11 displays an outstanding catalytic performance when compared to other reported xylanases, and CBM36 enhances the activity by increasing the affinity to the substrate. Addition of Ca2+ boosted the activity of full-length enzyme, but not the truncated variant lacking the CBM, against the insoluble substrate, suggesting that CBM36 plays a role in the Ca2+-dependent increase of catalytic efficiency. Graphical abstract Image 1 Highlights • A GH11 xylanase, NtSymX11, from a termite symbiotic bacterium was characterized. • NtSymX11 consists of a catalytic domain and two tandem CBM36s. • NtSymX11 displayed a prominent catalytic performance compared to other xylanases. • CBM36 decreased the enzyme stability at acidic pH and high temperature. • CBM36 increased the activity to the insoluble substrate in a Ca2+-dependent manner. [ABSTRACT FROM AUTHOR]

Three experimental groups were designed to study the effects of different exogenous nutrients on a composting process and the degradation extents of cellulose, hemicellulose, and lignin. Hickory shell was the main raw material, and spent mushroom substrate and composted chicken manure were used as exogenous nutrients. The C/N ratios of these groups were adjusted to 34 by using soybean meal. The study results showed that the duration of high-temperature stage of composting was shortened and the maturity of composting products was improved by adding exogenous nutrients. The seed germination index with spent mushroom substrate and composted chicken manure were 112% and 101%. The addition of exogenous nutrients reduced the composting weight loss and increase the degradation extents of cellulose (=64.6%), hemicellulose (=82.4%), and lignin (=64.3%). In particular, the degradation of compost products with composted chicken manure was higher than that of the composting products with the spent mushroom substrate. In the hickory shell composting system, bacteria played a dominant role in the initial and thermophilic phase, and the lignin degradation is related to the quantity of fungi and actinomycetes in composting process. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Actinomycetes were added into straw composting from wheat, rice, corn and soybean. • Bacterial and actinomycetic community composition were analyzed during composting. • Key factor affecting lignocellulose degradation and enzyme activities were discerned. • Inoculation increased 34.3% lignocellulose degradation and 8.3% enzyme activity. • Combined adding inoculants and urea was suggested to improve the inoculation effect. Abstract This study was conducted to assess the effect of thermophilic actinomycetes inoculation on the lignocellulose degradation, enzyme activities and microbial community during different types of straw composting from wheat, rice, corn and soybean. The results showed that actinomycetes inoculation not only changed the structure of actinomycetic and bacterial community but also accelerated the degradation of cellulose, hemicellulose and lignin and increased the key enzymes activities including CMCase, Xylanase, manganese peroxidase, lignin peroxidase and laccase during composting particularly from wheat straw and rice straw. The key enzyme and physiochemical parameters which affected organic fractions degradation have been identified by redundancy analysis. The combined application of actinomycete inoculation and urea addition as a source of nitrogen was suggested to regulate the key enzyme activities and lignocellulose degradation, which lays a foundation for effectively managing organic wastes from different types of crop straws by composting. [ABSTRACT FROM AUTHOR]

The fungus Penicillium purpurogenum grows on a variety of natural carbon sources and secretes a large number of enzymes which degrade the polysaccharides present in lignocellulose. In this work, the gene coding for a novel endoxylanase has been identified in the genome of the fungus. This gene (xynd) possesses four introns. The cDNA has been expressed in Pichia pastoris and characterized. The enzyme, XynD, belongs to family 10 of the glycoside hydrolases. Mature XynD has a calculated molecular weight of 40,997. It consists of 387 amino acid residues with an N-terminal catalytic module, a linker rich in ser and thr residues, and a C-terminal family 1 carbohydrate-binding module. XynD shows the highest identity (97%) to a putative endoxylanase from Penicillium subrubescens but its highest identity to a biochemically characterized xylanase (XYND from Penicillium funiculosum) is only 68%. The enzyme has a temperature optimum of 60 °C, and it is highly stable in its pH optimum range of 6.5-8.5. XynD is the fourth biochemically characterized endoxylanase from P. purpurogenum, confirming the rich potential of this fungus for lignocellulose biodegradation. XynD, due to its wide pH optimum and stability, may be a useful enzyme in biotechnological procedures related to this biodegradation process. [ABSTRACT FROM AUTHOR]

Rice husk is an abundant agricultural waste generated from rice production, but its application is limited. Considering its complex components, the rice husk was hydrolyzed by different enzymes to enhance its saccharification. In this study, saccharification of the rice husk by cellulase, xylosidase, and xylanase was first investigated. The synergistic effect of LPMO on the above hydrolases and different enzyme combinations in the saccharification process was then explored. Thereafter, the formulation of the enzyme cocktail and the degradation conditions were optimized to obtain the highest saccharification efficiency. The results showed that the optimum enzyme cocktail consists of Celluclast 1.5 L (83.3 mg/g substrate), the key enzymes in the saccharification process, worked with Bp Xyl (20 mg/g substrate), Bp Xyn11 (24 mg/g substrate), and R17L/N25G (4 mg/g substrate). The highest reducing sugar concentration (1.19 mg/mL) was obtained at pH 6.0 and 60 ℃ for 24 h. Fourier transform infrared spectroscopy and scanning electron microscopy were employed to characterize the structural changes in the rice husk after degradation. The results showed that the key chemical bonds in cellulose and hemicellulose were broken. This study illuminated the concept of saccharifying lignocellulose from rice husk using LPMO synergistically assisted combined-hydrolase including cellulase, xylosidase, and xylanase, and provided a theoretical basis for lignocellulose biodegradation. • Synergistic effect of xylanase and xylosidase with cellulase is identified to saccharify rice husk. • LPMO can synergize with the above three hydrolases to saccharify rice husk. • A combination of all four enzymes provided 1.19 mg/mL of reducing sugar production. • The conditions of the degradation process are optimized. [ABSTRACT FROM AUTHOR]

Abstract The characteristics of bio-oil produced from biomass pyrolysis can be improved by co-feeding waste materials. In this work, co-pyrolysis of lignocellulosic biomass with six different waste plastics (waste tyre (WT), polylactic acid (PLA), polystyrene (PS), polyethylene terephthalate (PET), polypropylene (PP) and high density polyethylene (HDPE)) were conducted in a thermogravimetric analyser to study thermal decomposition of the mixtures. The distributed activation energy model (DAEM) was applied to pure feedstocks at 5 and 10 °C/min heating rates to fit the kinetic parameters. The model was used to simulate the co-pyrolysis of biomass/plastic mixtures assuming additive effect of components at different weight proportions and heating rates. Profiles of the fraction of mass remaining for mixtures at 100 °C/min were reproduced with a remarkable agreement. Discrepancies between the experimental and calculated profiles were considered as a measure of the extent of interactions occurring in the co-pyrolysis. Projections of the behaviour of mixtures under flash pyrolysis conditions were performed to study important aspects of the process, such as radical interactions and optimum working temperature. Highlights • The Distributed Activation Energy Model was applied to co-pyrolysis. • Mixtures of lignocellulosic biomass and plastic wastes were studied. • Different proportions of components and heating rates were successfully simulated. • Deviations of simulations from experiments were ascribed to interactions of solids. • Interactions depend on the nature and proportion of plastics and the heating rate. [ABSTRACT FROM AUTHOR]

Abstract The efficiency of enzymatic hydrolysis is reduced by the naturally recalcitrant complex polymers comprising lignocellulose. Increasing enzymatic conversion, which the complex macromolecules converted into simpler molecules, is still had to be overcome. High hydrostatic pressure (HHP), an emerging technology, is expected to ameliorate the situation. The effects of enzymatic hydrolysis after HHP pretreatment on pumpkin lignocellulose were studied and compared with hydrothermal and alkaline pretreatment. Further investigation was performed to evaluate the effect of enzymatic hydrolysis of pumpkin combined with HHP treatment. The samples underwent HHP treatment simultaneously exhibited overall better performance in enzymatic hydrolysis than the untreated. The highest glucose yield of 91.2% and xylose yield of 84.2% was achieved when 400 MPa HHP with high enzyme loading was applied. HHP exerted positive effects on enzyme-substrate interactions during the enzymatic hydrolysis of lignocellulose, which implied that HHP technology combined with enzymatic hydrolysis could be used to pretreat pumpkin pomace. Highlights • Cellulose and hemicellulose removal significantly increased after hydrothermal and alkaline pretreatment. • The highest yields of glucose and xulose were achieved at 400 MPa with high enzyme loading. • High hydrostatic pressure exerted positive effects on enzyme-lignocellulose complex interactions. • The method of high hydrostatic pressure was established on the conversion of lignocellulose. [ABSTRACT FROM AUTHOR]

The generation of a complex microbial consortium is a promising approach for efficient biomass decomposition. An anaerobic thermophilic alkaliphilic microbial consortium with efficient degradation ability was screened from bovine manure compost using non-pretreated milling corn stover (CS) and rice straw (RS). A stable microbial consortium ISHI-3 with high degradation ability for CS and RS was isolated by the roll tube technique. ISHI-3 comprised Herbivorax saccincola and bacteria belonging to the classes Pelotomaculum, Tepidanaerobacter , and Tepidimicrobium , as determined by DGGE of the PCR-generated 16S rRNA genes. Furthermore, metagenomics analysis using a 16S rRNA library was carried out to determine the bacterial distribution during degradation of CS and RS. H. saccincola and bacteria belonging to Pelotomaculum were relatively abundant in the beginning to middle periods of culture with CS and RS whereas bacteria belonging to Tepidanaerobacter and Tepidimicrobium gradually increased in the population during the later stages. To understand the role of non-cellulolytic bacteria in the consortium, novel strains ET1 and GL4, which were most closely related to Tepidimicrobium ferriphilum and Tepidanaerobacter acetatoxydans , were isolated from ISHI-3. Based on their carbon source usage, morphology, and phylogenetic analysis, we propose that strains ET1 and GL4 should be classified as a novel genus or species. Bacteria ET1 and GL4 can utilize different organic compounds as carbon and energy sources such as organic acids, alcohols, sugars, and amino acids, showing a preference for organic acids and alcohols rather than sugars such as glucose and cellobiose. These results indicated that ET1 and GL4 help to accelerate efficient lignocellulose degradation of H. saccincola . [ABSTRACT FROM AUTHOR]