Transformation Of Lignocellulose Research Articles

Highly Efficient Production of Furfural from Corncob by Barley Hull Biochar-Based Solid Acid in Cyclopentyl Methyl Ether–Water System

Furfural, an important biobased compound, can be synthesized through the chemocatalytic conversion of D-xylose and hemicelluloses from lignocellulose. It has widespread applications in the production of valuable furans, additives, resins, rubbers, synthetic fibers, polymers, plastics, biofuels, and pharmaceuticals. By using barley hulls (BHs) as biobased support, a heterogeneous biochar Sn-NUS-BH catalyst was created to transform corncob into furfural in cyclopentyl methyl ether–H2O. Sn-NUS-BH had a fibrous structure with voids, a large comparative area, and a large pore volume, which resulted in more catalytic active sites. Through the characterization of the physical and chemical properties of Sn-NUS-BH, it was observed that the Sn-NUS-BH had tin dioxide (Lewis acid sites) and a sulfonic acid group (Brønsted acid sites). This chemocatalyst had good thermostability. At 170 °C for 20 min, Sn-NUS-BH (3.6 wt%) was applied to transform 75 g/L of corncob with ZnCl2 (50 mM) to generate furfural (80.5% yield) in cyclopentyl methyl ether–H2O (2:1, v/v). This sustainable catalytic process shows great promise in the transformation of lignocellulose to furfural using biochar-based chemical catalysts.

Characterization of a novel cellobiose phosphorylase with broad optimal pH range from a tailings pond macrogenomic library

Glucose-1-phosphate, a crucial pharmaceutical intermediate, can be generated through the synergistic transformation of lignocellulose using cellulase and cellobiose phosphorylase (CBP), thus holding promise for a profitable biorefinery process. However, the reported optimal pH range of CBPs (6.0–7.5) does not align with that of cellulase (4.8), resulting in suboptimal efficiency in the one-pot conversion of cellulose to glucose-1-phosphate. In this study, we identified a novel cellobiose phosphorylase, CBP1942, comprising 811 amino acid residues (92.5 kDa), in tailing pond macrogenomes, exhibiting identity of 60% to 75% with reported CBPs. CBP1942 was efficiently expressed in E. coli BL21 and purified with His tagging. It maintains over 90% enzyme activity across pH 4–9. Compared to the benchmark CtCBP (GenBank ID: AAL67138.1), CBP1942 displays a 1.2-fold increase in specific enzyme activity at the optimal cellulase temperature (50 °C), indicating its superior suitability for cellulase compounding. CBP1942 exhibits Km and kcat values of 6.69 mM and 8.83 s−1, respectively, with a kcat/Km ratio 6.6 times higher than CtCBP, suggesting superior catalytic efficiency. Notably, CBP1942 shows remarkable thermal stability, retaining 94.67% enzyme activity after 3 h at 50 °C, while CtCBP retains only 78.33%. Additionally, CBP1942 complexed with cellulase enhances the conversion of corn stover, resulting in a 6.2-fold increase in glucose-1-phosphate yield compared to CtCBP. These findings indicate CBP1942’s potential as an industrial enzyme for corn stover conversion to glucose-1-phosphate.

Efficient in situ saccharification of microcrystalline cellulose over immobilized cellulase on magnetic biochar in ionic liquid media

Saccharification serves as the entry point for the biomass into biorefinery schemes and plays a vital role in lignocellulose transformation towards bio-fuels and platform molecules. Herein, an efficient in situ saccharification of lignocellulose under the mediation of ionic liquid of [DMIM]DMP is reported, using a series of magnetically-separable biochars as catalyst supports with immobilized endoglucanase Cel5A. The physicochemical properties of these magnetic biochars with immobilized endoglucanase (abbreviated as MBIE) were thoroughly characterized by FTIR, TG, SEM/EDX, XRD, XPS, N2 physisorption, UV–vis and VSM. The results revealed that the endoglucanase, which functions as the catalytically active species, was immobilized on the biochar via simultaneous physical adsorption and covalent attachment. The extremely high surface area of biochar endows a high loading of endoglucanase and easy diffusion of reactant within the catalyst’s framework. The zeta potential of the catalyst was − 7.06 mV, indicating its excellent stability. MBIE with immobilizing endoglucanase of 484.36 mg/g exhibited the superior performance under a biphasic system (IL/water v/v 5:1), affording a glucose yield of 932.5 mg/g. The activity of MBIE remained constant after 10 consecutive cycles via magnetic recycling. This work demonstrates an efficient in situ saccharification process catalyzed by the developed MBIE with high activity and excellent regeneration ability.

High concentration bioethanol production from corn stalk via enhanced pretreatment with ionic liquids

The transformation of lignocellulose into bioethanol is of great significance for energy security and environmental protection. Traditionally, the concentration of ethanol obtained by fermentation does not exceed 7 % (v/v), resulting in high cost of rectification (about 100 t water are needed to produce 1 t ethanol) and a large amount of wastewater, which is not suitable for industrial production. In this study, producting high concentration bioethanol from ionic liquid pretreated corn stalk integrated by feed-batch method was proposed. The cellulose content and the lignin removal rate of the corn stalk pretreated by [BHEM]mesy-ethylene glycol co-solvent system (rich-cellulose material) were 91 % and 93 %, respectively. The co-solvent system showed stable pretreatment efficiency after amplification of 20 times. Observably, the rich-cellulose material became easier to enzymolysis because the lower crystallinity from XRD, less lignin from CLSM and so on. The optimal enzymolysis conditions were 160 EGU/g cellulose, 50 ℃, pH = 4.8, 96 h, under which the yield of glucose could reach 90 %. The tolerance limit of Saccharomyces cerevisiae to glucose concentration is 0.3 g/L. The viscosity of enzymolysis materials was one of the main factors limiting the efficiency of enzymolysis by rheometer, and the 5 % concentration of materials was the most suitable for enzymolysis. Significantly, by feed-batch method, the glucose concentration reached 250 g/L with the yield of 100 %. The ethanol concentration is 93 g/L with the yield of 73 %. This study provided the possibility for industrialization of bioethanol production.

Unraveling the roles of coastal bacterial consortia in degradation of various lignocellulosic substrates.

Lignocellulose, as the most abundant natural organic carbon on earth, plays a key role in regulating the global carbon cycle, but there have been only few studies in marine ecosystems. Little information is available about the extant lignin-degrading bacteria in coastal wetlands, limiting our understanding of their ecological roles and traits in lignocellulose degradation. We utilized in situ lignocellulose enrichment experiments coupled with 16S rRNA amplicon and shotgun metagenomics sequencing to identify and characterize bacterial consortia attributed to different lignin/lignocellulosic substrates in the southern-east intertidal zone of East China Sea. We found the consortia enriched on woody lignocellulose showed higher diversity than those on herbaceous substrate. This also revealed substrate-dependent taxonomic groups. A time-dissimilarity pattern with increased alpha diversity over time was observed. Additionally, this study identified a comprehensive set of genes associated with lignin degradation potential, containing 23 gene families involved in lignin depolymerization, and 371 gene families involved in aerobic/anaerobic lignin-derived aromatic compound pathways, challenging the traditional view of lignin recalcitrance within marine ecosystems. In contrast to similar cellulase genes among the lignocellulose substrates, significantly different ligninolytic gene groups were observed between consortia under woody and herbaceous substrates. Importantly, we not only observed synergistic degradation of lignin and hemi-/cellulose, but also pinpointed the potential biological actors at the levels of taxa and functional genes, which indicated that the alternation of aerobic and anaerobic catabolism could facilitate lignocellulose degradation. Our study advances the understanding of coastal bacterial community assembly and metabolic potential for lignocellulose substrates. IMPORTANCE It is essential for the global carbon cycle that microorganisms drive lignocellulose transformation, due to its high abundance. Previous studies were primarily constrained to terrestrial ecosystems, with limited information about the role of microbes in marine ecosystems. Through in situ lignocellulose enrichment experiment coupled with high-throughput sequencing, this study demonstrated different impacts that substrates and exposure times had on long-term bacterial community assembly and pinpointed comprehensive, yet versatile, potential decomposers at the levels of taxa and functional genes in response to different lignocellulose substrates. Moreover, the links between ligninolytic functional traits and taxonomic groups of substrate-specific populations were revealed. It showed that the synergistic effect of lignin and hemi-/cellulose degradation could enhance lignocellulose degradation under alternation of aerobic and anaerobic conditions. This study provides valuable taxonomic and genomic insights into coastal bacterial consortia for lignocellulose degradation.

Ferulic acid production from wheat bran by integration of enzymatic pretreatment and a cold-adapted carboxylesterase catalysis

High-value chemical production from natural lignocellulose transformation is a reliable waste utilization approach. A gene encoding cold-adapted carboxylesterase in Arthrobacter soli Em07 was identified. The gene was cloned and expressed in Escherichia coli to obtain a carboxylesterase enzyme with a molecular weight of 37.2 KDa. The activity of the enzyme was determined using α-naphthyl acetate as substrate. Results showed that the optimum enzyme activity of carboxylesterase was at 10 °C and pH 7.0. It was also found that the enzyme could degrade 20 mg enzymatic pretreated de-starched wheat bran (DSWB) to produce 235.8 μg of ferulic acid under the same conditions, which was 5.6 times more than the control. Compared to the chemical strategy, enzymatic pretreatment is advantageous because it is environmentally friendly, and the by-products can be easily treated. Therefore, this strategy provides an effective method for high-value utilization of biomass waste in agriculture and industry.

Synthesis of furoic acid from biomasses by sequential catalysis with fish scale-rice husk-based heterogeneous chemocatalyst and dehydrogenase biocatalyst

In this work, furfural was effectively converted to furoic acid (FCA) by using biological macromolecules as raw materials in tandem reaction with chemical biological catalysts. Firstly, a biochar-based heterogeneous catalyst Sn-FS-RH was prepared using equal mass of fish scale (FS) and rice husk (RH) as carriers. Different biomasses (such as poplar wood, winter bamboo shoot shell, corn cob, corn straw, reed leaf, peanut shell, rape straw, and potato shell) were transformed into furfural with Sn-FS-RH in deep eutectic solvent choline chloride:Maleic acid (ChCl:MLA)-H2O (10:90, v/v; 170 °C), and the furfural yield from corn cob-derived xylose reached the highest (70.5% yield, based on xylose) after 15 min of catalysis. The mechanism of Sn-FS-RH-catalyzed the transformation of lignocellulose to furfural was interpreted in ChCl:MLA-H2O. One liter of xylose-hydrolysate was obtained after acid hydrolysis of biomass. The preparation of FUR was generally carried out in a 10 liter of autoclave reactor containing 75 g biomass, 36 g Sn-FS-RH catalyst, 100 g ChCl:MLA, and 20 g ZnCl2. The reactor was stirred at 170 ℃ for 15 min at 500 rpm. It was observed that the by-products (formic acid, levulinic acid, and 5-hydroxymethylfurfural) formed in the transformation of lignocellulose to furfural had somewhat inhibitory effect on the formation of furoic acid from furfural bioconversion. After 24–72 h, Escherichia coli HMFOMUT cells containing dehydrogenase could transform fully furfural derived from different biomass (30–90 mM) into furoic acid. This two-step chemoenzymatic strategy was an efficient way to transform biomacromolecules into biofurans in a sustainable medium.

Advances in catalytic valorization of cellulose into value-added chemicals and fuels over heterogeneous catalysts

The valorization of lignocellulose has received increasing attention due to the diminishing of conventional fossil energy (coal, petroleum, and natural gas). Lignocellulosic biomass is the most important form of biomass, which is naturally abundant, widely distributed, easily accessible, and renewable in earth. Upgrading the nonedible lignocellulosic biomass into various fine-chemicals and liquid fuels is of great importance to the sustainable development of mankind and society. Heterogeneous catalysts have played a significant role in the transformation of lignocellulose, owing to their easy recovery, environmentally friendly, and stability feature. This review focuses on the conversion of lignocellulosic biomass into alcohols, acids, furan derivatives, ethylene glycol, and liquid hydrocarbon fuels using heterogeneous catalysts. A brief outlook is supplied at the end of this review to emphasize the challenges and prospective with respective to this interesting and important field.

Efficient delignification of sugarcane bagasse by Fenton oxidation coupled with ultrasound-assisted NaOH for biotransformation from Agaricus sinodeliciosus var. Chaidam

Sugarcane bagasse (SCB), a widely available lignocellulosic by-product, could be potentially used in macrofungal bioconversion for high-value bioactive compounds. For macrofungus with poor lignin degradation capacity, its recalcitrant lignin structure blocked the release of fermentable sugars for cell growth. Herein, the main objective was to construct an effective delignification pretreatment strategy for SCB biotransformation and synthesis of bioactive substances by Agaricus sinodeliciosus var. Chaidam. Different pretreatments including chemical (alkali and Fenton oxidation) and ultrasound methods were used to intensify the delignification process. Physico-chemical characteristics of native and pretreated SCB were examined via XRD, XPS, FT-IR and 13C ssNMR to characterize crystallinity index, surface lignin and chemical structure. Lignocellulose-degrading enzymes were also used to assess the ability of the macrofungus to degrade SCB. By comparing morphological structure, chemical composition and fermentation characteristics, a suitable multiple sequential pretreatment method was finally identified. Our findings revealed that Fenton-ultrasound-alkali pre-treatment has an optimum delignification effect on SCB with never-uncovered excellent ability to detoxify harmful substances produced by Fenton oxidation. Under this pretreatment condition, the cellulose content was increased by 106.45%, whereas hemicelluloses and lignin were decreased by 48.34% and 74.15%, respectively. The macrofungal growth, intracellular polysaccharides, total phenols and terpenoids formation were 2.4, 1.46, 1.36 and 1.66 times higher than those of the untreated, respectively. Fermentation kinetic results showed outstanding fit and prediction of macrofungal growth and enzymatic activity secretion on above pretreated SCB. This study shed light on developing a novel pretreatment strategy for low-cost SCB lignocellulose transformation into high-value products.

Selective preparation of bio‐based high‐value chemical of cresol with Cu‐MOF catalyst

AbstractBACKGROUNDThe development of efficient synthetic pathways for bio‐based chemicals is beneficial to sustainable development of the chemical industry. However, directional production of phenolic chemicals using lignocellulose remains a challenging issue, because the reaction paths as well as intermediates in the catalytic transformation of lignocellulose are often complicated.RESULTSBio‐based cresol can be selectively prepared from lignocellulose biomass. This steerable transformation has been achieved by lignocellulose catalytic pyrolysis to aromatic intermediates over a magnetic oxide‐modified zeolite catalyst (Fe3O4@HZSM‐5) and intermediate hydroxylation to cresol over a metal–organic framework catalyst (Cu‐MOF). Based on the analysis of intermediates and on catalyst characterization, the corresponding reaction pathways are put forward. Using the Cu‐MOF catalyst, the highest selectivity of cresol (81.5%) and the highest conversion (76.8%) were gained at 40 °C in 4 h.CONCLUSIONSThe work presented proves that an important phenolic chemical (cresol) can be selectively prepared from lignocellulose raw materials. The Cu‐MOF catalyst shows superior performance and good reusability in the bio‐cresol synthesis. Reactive oxygen species take a prominent role in the cresol synthesis. © 2022 Society of Chemical Industry (SCI).

Study on dynamic changes of microbial community and lignocellulose transformation mechanism during green waste composting.

There are few reports on the material transformation and dominant microorganisms in the process of greening waste (GW) composting. In this study, the target microbial community succession and material transformation were studied in GW composting by using MiSeq sequencing and PICRUSt tools. The results showed that the composting process could be divided into four phases. Each phase of the composting appeared in turn and was unable to jump. In the calefactive phase, microorganisms decompose small molecular organics such as FA to accelerate the arrival of the thermophilic phase. In the thermophilic phase, thermophilic microorganisms decompose HA and lignocellulose to produce FA. While in the cooling phase, microorganisms degrade HA and FA for growth and reproduction. In the maturation phase, microorganisms synthesize humus using FA, amino acid and lignin nuclei as precursors. In the four phases of the composting, different representative genera of bacteria and fungi were detected. Streptomyces, Myceliophthora and Aspergillus, maintained high abundance in all phases of the compost. Correlation analysis indicated that bacteria, actinomycetes and fungi had synergistic effect on the degradation of lignocellulose. Therefore, it can accelerate the compost process by maintaining the thermophilic phase and adding a certain amount of FA in the maturation phase.

High value utilization of biomass: selective catalytic transformation of lignocellulose into bio-based 2,5-dimethylphenol

A new strategy for the synthesis of high-value biochemical 2,5-dimethylphenol was constructed by lignocellulose catalytic pyrolysis and selective hydroxylation.

Selective upgrading of biomass-derived benzylic ketones by (formic acid)–Pd/HPC–NH2 system with high efficiency under ambient conditions

Selective upgrading of biomass-derived benzylic ketones by (formic acid)–Pd/HPC–NH2 system with high efficiency under ambient conditions

Transformation of lignocellulose to starch‐like carbohydrates by organic acid‐catalyzed pretreatment and biological detoxification

Corn dry milling provides a mature model for lignocellulose biorefinery process. To copy this technical success, a crucial step is to transform lignocellulose into starch-like carbohydrates (SLC), similar to milled corn grain and in a similar fashion to corn dry milling. The transformation process should be zero wastewater generation and sufficient fermentable sugar conservation; the product should be in solid particle form, free of toxic residues, and high enzymatic hydrolysis yield and fermentability. Here we designed and verified a SLC transformation process by (i) biodegradable oxalic acid-catalyzed pretreatment, and (ii) simultaneous biodegradation of inhibitors and oxalic acid catalyst. The oxalic acid catalyst was effective on disrupting the lignocellulose structure and also biodegradable at low pH value. The biodetoxification fungus Paecilomyces variotii FN89 was capable of degrading the furan/phenolic aldehydes and oxalic acid simultaneously and ultimately, while the fermentable sugars were well preserved. The obtained SLC from wheat straw and corn stover were similar to dry milled corn meal in terms of morphological properties, fermentable sugar contents, enzymatic hydrolysis yield, elemental contents, and free of inhibitors and acid catalyst. The bioconversion of starch-like wheat straw and corn stover produced 78.5 and 75.3 g/L of ethanol (9.9% and 9.5%, v/v) with the yield of 0.47 and 0.45 g ethanol/g cellulose/xylose, respectively, compared with 78.7 g/L (10.0%, v/v) from corn meal and the yield of 0.48 g ethanol/g starch. Mass balances suggest that the ethanol yield, wastewater generation, and elemental recycling of the SLC from lignocellulose were essentially the same as those of corn meal.

Crystal structure and functional characterization of an oligosaccharide dehydrogenase from Pycnoporus cinnabarinus provides insights into fungal breakdown of lignocellulose

BackgroundFungal glucose dehydrogenases (GDHs) are FAD-dependent enzymes belonging to the glucose-methanol-choline oxidoreductase superfamily. These enzymes are classified in the “Auxiliary Activity” family 3 (AA3) of the Carbohydrate-Active enZymes database, and more specifically in subfamily AA3_2, that also includes the closely related flavoenzymes aryl-alcohol oxidase and glucose 1-oxidase. Based on sequence similarity to known fungal GDHs, an AA3_2 enzyme active on glucose was identified in the genome of Pycnoporus cinnabarinus, a model Basidiomycete able to completely degrade lignin.ResultsIn our work, substrate screening and functional characterization showed an unexpected preferential activity of this enzyme toward oligosaccharides containing a β(1→3) glycosidic bond, with the highest efficiency observed for the disaccharide laminaribiose. Despite its sequence similarity to GDHs, we defined a novel enzymatic activity, namely oligosaccharide dehydrogenase (ODH), for this enzyme. The crystallographic structures of ODH in the sugar-free form and in complex with glucose and laminaribiose unveiled a peculiar saccharide recognition mechanism which is not shared with previously characterized AA3 oxidoreductases and accounts for ODH preferential activity toward oligosaccharides. The sugar molecules in the active site of ODH are mainly stabilized through CH-π interactions with aromatic residues rather than through hydrogen bonds with highly conserved residues, as observed instead for the fungal glucose dehydrogenases and oxidases characterized to date. Finally, three sugar-binding sites were identified on ODH external surface, which were not previously observed and might be of importance in the physiological scenario.ConclusionsStructure–function analysis of ODH is consistent with its role as an auxiliary enzyme in lignocellulose degradation and unveils yet another enzymatic function within the AA3 family of the Carbohydrate-Active enZymes database. Our findings allow deciphering the molecular determinants of substrate binding and provide insight into the physiological role of ODH, opening new perspectives to exploit biodiversity for lignocellulose transformation into fuels and chemicals.

Optimization of OPEFB lignocellulose transformation process through ionic liquid [TEA][HSO4] based pretreatment

Research on the transformation of Oil Palm Empty Fruit Bunches (OPEFB) through pretreatment process using ionic liquid triethylammonium hydrogen sulphate (IL [TEA][HSO4]) was completed. The stages of the transformation process carried out were the synthesis of IL with the one-spot method, optimization of IL composition and pretreatment temperature, and IL recovery. The success of the IL synthesis stage was analyzed by FTIR, H-NMR and TGA. Based on the results obtained, it showed that IL [TEA][HSO4] was successfully synthesized. This was indicated by the presence of IR absorption at 1/λ = 2814.97 cm−1, 1401.07 cm−1, 1233.30 cm−1 and 847.92 cm−1 which were functional groups for NH, CH3, CN and SO2, respectively. These results were supported by H-NMR data at δ (ppm) = 1.217–1.236 (N–CH2–CH3), 3.005–3.023 (–H), 3.427–3.445 (N–H+) and 3.867 (N+H3). The TGA results showed that the melting point and decomposition temperature of the IL were 49 °C and 274.3 °C, respectively. Based on pretreatment optimization, it showed that the best IL composition for cellulose production was 85 wt%. Meanwhile, temperature optimization showed that the best temperature was 120 °C. In these two optimum conditions, the cellulose content was obtained at 45.84 wt%. Testing of IL [TEA][HSO4] recovery performance for reuse has shown promising results. During the pretreatment process, IL [TEA][HSO4] recovery effectively increased the cellulose content of OPEFB to 29.13 wt% and decreased the lignin content to 32.57%. The success of the recovery process is indicated by the increasing density properties of IL [TEA][HSO4]. This increase occurs when using a temperature of 80–100 °C. The overall conditions obtained from this work suggest that IL [TEA][HSO4] was effective during the transformation process of OPEFB into cellulose. This shows the potential of IL [TEA][HSO4] in the future in the renewable energy sector.

Role of Microbial Biomechanics in Composting with Special Reference to Lignocellulose Biomass Digestion

Biomass transformation of lignocellulose into compost offers ‘green’ technology for sustainable agricultural development. So far, biomass conversion into compost outweighs fossil resources and other conversational techniques due to the low production cost and environmental pollution reduction. Although composting has aesthetically been resorted to in the digestibility of lignocellulose biomass, its realization has keenly been directed towards adding chemical reagents. However, inclining massively to this treatment instigated research bias as microorganisms’ biomass digestibility remains mostly inadequate. Besides, proliferated growth and activities of microorganisms native to lignocellulose biomass are usually disrupted by chemical treatment. The microbial flora (fungi, bacteria, actinomycetes, archaea, and yeast) involved in composting synthesizes complex biocatalysts (enzymes) that are crucial for solubilizing the biopolymers of lignocellulose materials at a density of 1012 cells g-1. Filamentous fungi are by far excellent degraders of lignocellulose in nature. To adequately ensure sustainable lignocellulose digestibility, microbial engineers must subject research studies to surpassing conditions (feedstock formulation and management processes) suitable for inducing ligninolytic, cellulolytic, and hemicellulolytic enzymes. Hence, the state-of-the-art-method of this review provides insights that relate to mechanisms of microbial reactions on the digestibility of lignocellulose biomass during composting.

Recent Advances in Photocatalytic Transformation of Carbohydrates Into Valuable Platform Chemicals

In response to the less accessible fossil resources and deteriorating environmental problems, catalytic conversion of the abundant and renewable lignocellulosic biomass to replace fossil resources for the production of value-added chemicals and fuels is of great importance. Depolymerization of carbohydrate and its derivatives can obtain a series of C5-C6 monosaccharides (e.g., glucose and xylose) and their derived platform compounds (e.g., HMF and furfural). Selective transformation of lignocellulose using sustainable solar energy via photocatalysis has attract broad interest from a growing scientific community. The unique photogenerated reactive species (e.g., h+, e−, •OH, •O2−, and 1O2), novel reaction pathways as well as the mild reaction conditions make photocatalysis a “dream reaction.” This review is aimed to provide an overview of the up-to-date contributions achieved in the selective photocatalytic transformation of carbohydrate and its derivatives. Photocatalytic methods, properties and merits of different catalytic systems are well summarized. We then put forward future perspective and challenges in this field.

Whole-Genome Sequence of Brevibacillus borstelensis SDM, Isolated from a Sorghum-Adapted Microbial Community

The isolation of novel microbes from environmental samples continues to be a key strategy for the discovery of new metabolic capacities for the degradation and transformation of lignocellulose. We report the draft genome sequence of a new strain of Brevibacillus borstelensis isolated from a sorghum-adapted microbial community derived from a compost sample.

Fungal Pretreatments on Non-Sterile Solid Digestate to Enhance Methane Yield and the Sustainability of Anaerobic Digestion

Fungi can run feedstock pretreatment to improve the hydrolysis and utilization of recalcitrant lignocellulose-rich biomass during anaerobic digestion (AD). In this study, three fungal strains (Coprinopsis cinerea MUT 6385, Cyclocybe aegerita MUT 5639, Cephalotrichum stemonitis MUT 6326) were inoculated in the non-sterile solid fraction of digestate, with the aim to further (re)use it as a feedstock for AD. The application of fungal pretreatments induced changes in the plant cell wall polymers, and different profiles were observed among strains. Significant increases (p < 0.05) in the cumulative biogas and methane yields with respect to the untreated control were observed. The most effective pretreatment was carried out for 20 days with C. stemonitis, causing the highest hemicellulose, lignin, and cellulose reduction (59.3%, 9.6%, and 8.2%, respectively); the cumulative biogas and methane production showed a 182% and 214% increase, respectively, compared to the untreated control. The increase in AD yields was ascribable both to the addition of fungal biomass, which acted as an organic feedstock, and to the lignocellulose transformation due to fungal activity during pretreatments. The developed technologies have the potential to enhance the anaerobic degradability of solid digestate and untap its biogas potential for a further digestion step, thus allowing an improvement in the environmental and economic sustainability of the AD process and the better management of its by-products.