Sugarcane bagasse derived xylooligosaccharides produced by an arabinofuranosidase/xylobiohydrolase from Bifidobacterium longum in synergism with xylanases

Arabinoxylan is a major hemicellulose in the sugarcane plant cell wall with arabinose decorations that impose steric restrictions on the activity of xylanases against this substrate. Enzymatic removal of the decorations by arabinofuranosidases can allow a more efficient arabinoxylan degradation by xylanases. Here we produced and characterized a recombinant Bifidobacterium longum arabinofuranosidase from glycoside hydrolase family 43 (BlAbf43) and applied it, together with GH10 and GH11 xylanases, to produce xylooligosaccharides (XOS) from wheat arabinoxylan and alkali pretreated sugarcane bagasse. The enzyme synergistically enhanced XOS production by GH10 and GH11 xylanases, being particularly efficient in combination with the latter family of enzymes, with a degree of synergism of 1.7. We also demonstrated that the enzyme is capable of not only removing arabinose decorations from the arabinoxylan and from the non-reducing end of the oligomeric substrates, but also hydrolyzing the xylan backbone yielding mostly xylobiose and xylose in particular cases. Structural studies of BlAbf43 shed light on the molecular basis of the substrate recognition and allowed hypothesizing on the structural reasons of its multifunctionality.

Complete genome sequence and transcriptome response to vitamin C supplementation of Novacetimonas hansenii SI1 - producer of highly-stretchable cellulose

Novacetimonas hansenii SI1, previously known as Komagataeibacter hansenii, produces bacterial nanocellulose (BNC) with unique ability to stretch. The addition of vitamin C in the culture medium increases the porosity of the membranes and their stretchability making them highly moldable. To better understand the genetic background of this strain, we obtained its complete genome sequence using a hybrid sequencing and assembly strategy. We described the functional regions in the genome which are important for the synthesis of BNC and acetan-like II polymer. We next investigated the effect of 1% vitamin C supplementation on the global gene expression profile using RNA sequencing. Our transcriptomic readouts imply that vitamin C functions mainly as a reducing agent. We found that the changes in cellular redox status are balanced by strong repression of the sulfur assimilation pathway. Moreover, in the reduced conditions, glucose oxidation is decreased and alternative pathways for energy generation, such as acetate accumulation, are activated. The presence of vitamin C negatively influences acetan-like II polymer biosynthesis, which may explain the lowered yield and changed mechanical properties of BNC. The results of this study enrich the functional characteristics of the genomes of the efficient producers of the N. hansenii species. Improved understanding of the adaptation to the presence of vitamin C at the molecular level has important guiding significance for influencing the biosynthesis of BNC and its morphology.

Cellulolytic potential of mangrove bacteria Bacillus haynesii DS7010 and the effect of anthropogenic and environmental stressors on bacterial survivability and cellulose metabolism

Cellulose degrading bacterial diversity of Bhitarkanika mangrove ecosystem, India, was uncovered and the cellulose degradation mechanism in Bacillus haynesii DS7010 under the modifiers such as pH (pCO2), salinity and lead (Pb) was elucidated in the present study. The abundance of cellulose degrading heterotrophic bacteria was found to be higher in mangrove sediment than in water. The most potential strain, B. haynesii DS7010 showed the presence of endoglucanase, exoglucanase and β-glucosidase with the maximum degradation recorded at 48 h of incubation, with 1% substrate concentration at 41 °C incubation temperature. Two glycoside hydrolase genes, celA and celB were confirmed in this bacterium. 3D structure prediction of the translated CelA and CelB proteins showed maximum similarities with glycoside hydrolase 48 (GH48) and glycoside hydrolase 5 (GH5) respectively. Native PAGE followed by zymogram assay unveiled the presence of eight isoforms of cellulase ranged from 78 kDa to 245 kDa. Among the stressors, most adverse effect was observed under Pb stress at 1400 ppm concentration, followed by pH at pH 4. This was indicated by prolonged lag phase growth, higher reactive oxygen species (ROS) production, lower enzyme activity and downregulation of celA and celB gene expressions. Salinity augmented bacterial metabolism up to 3% NaCl concentration. Mangrove leaf litter degradation by B. haynesii DS7010 indicated a substantial reduction in cellulolytic potential of the bacterium in response to the synergistic effect of the stressors. Microcosm set up with the stressors exhibited 0.97% decrease in total carbon (C%) and 0.02% increase in total nitrogen (N%) after 35 d of degradation while under natural conditions, the reduction in C and the increase in N were 4.05% and 0.2%, respectively. The findings of the study suggest the cellulose degradation mechanism of a mangrove bacterium and its resilience to the future consequences of environmental pollution and climate change.

Exploring the cellulolytic activity of environmental mycobacteria

Although studies on non-tuberculous mycobacteria have increased in recent years because they cause a considerable proportion of infections, their cellulolytic system is still poorly studied. This study presents a characterization of the cellulolytic activities of environmental mycobacterial isolates derived from soil and water samples from the central region of Argentina, aimed to evaluate the conservation of the mechanism for the degradation of cellulose in this group of bacteria. The molecular and genomic identification revealed identity with Mycolicibacterium septicum. The endoglucanase and total cellulase activities were assessed both qualitatively and quantitatively and the optimal enzymatic conditions were characterized. A specific protein of around 56 kDa with cellulolytic activity was detected in a zymogram. Protein sequences possibly arising from a cellulase were identified by mass spectrometry-based shotgun proteomics. Results showed that M. septicum encodes for cellulose- and hemicellulose-related degrading enzymes, including at least an active β-1,4 endoglucanase enzyme that could be useful to improve its survival in the environment. Given the important health issues related to mycobacteria, the results of the present study may contribute to the knowledge of their cellulolytic system, which could be important for their ability to survive in many different types of environments.

Synergistic effect of two bacterial strains promoting anaerobic digestion of rice straw to produce methane

A large amount of agricultural waste causes global environmental pollution. Biogas production by microbial pretreatment is an important way to utilize agricultural waste resources. In this study, Sporocytophaga CG-1 (A, cellulolytic strain) was co-cultured with Bacillus clausii HP-1 (B, non-cellulolytic strain) to analyze the effect of pretreatment of rice straw on methanogenic capacity of anaerobic digestion (AD). The results showed that weight loss rate of filter paper of co-culture combination is 53.38%, which is 29.37% higher than that of A. The synergistic effect of B on A can promote its degradation of cellulose. The cumulative methane production rate of the co-culture combination was the highest (93.04 mL/g VS substrate), which was significantly higher than that of A, B and the control group (82.38, 67.28 and 67.70 mL/g VS substrate). Auxiliary bacteria can improve cellulose degradation rate by promoting secondary product metabolism. These results provide data support for the application of co-culture strategies in the field of anaerobic digestion practices.

Mechanism underlying effects of cellulose-degrading microbial inoculation on amino acid degradation and biosynthesis during composting

Amino acids are essential organic compounds in composting products. However, the mechanism underlying the amino acid metabolism during composting remains unclear. This study aims at exploring the impacts of inoculating cellulose-degrading microbes on amino acid metabolism during composting with mulberry branches and silkworm excrements. Cellulose-degrading microbial inoculation enhanced amino acid degradation by 18%-43% by increasing protease and sucrase activities and stimulating eight amino acid degradation pathways from the initial to thermophilic phases, with Enterococcus, Saccharomonospora, Corynebacterium being the dominant bacterial genera, but stimulated amino acid production by 54% by increasing sucrase and urease activities, decreasing β-glucosidase activities, and stimulating twenty-two amino acid synthesis pathways at the mature phase, with Thermobifida, Devosia, and Cellulosimicrobium being the dominant bacterial genera. The results suggest that cellulose-degrading microbial inoculation enhances amino acid degradation from the initial to thermophilic phases and biosynthesis at the mature phase, thereby improving the quality of organic fertilizer.

The bioaugmentation effect of microbial inoculants on humic acid formation during co-composting of bagasse and cow manure

The effective degradation of recalcitrant lignocellulose has emerged as a bottleneck for the humification of compost, and strategies are required to improve the efficiency of bagasse composting. Bioaugmentation is a promising method for promoting compost maturation and improving the quality of final compost. In this study, the bioaugmentation effects of microbial inoculants on humic acid (HA) formation during lignocellulosic composting were explored. In the inoculated group, the maximum temperature was increased to 72.5 °C, and the phenol-protein condensation and Maillard humification pathways were enhanced, thus increasing the HA content by 43.85%. After inoculation, the intensity of the microbial community interactions increased, particularly for fungi (1.4-fold). Macrogenomic analysis revealed that inoculation enriched thermophilic bacteria and lignocellulose-degrading fungi and increased the activity of carbohydrate-active enzymes and related metabolic functions, which effectively disrupted the recalcitrant structure of lignocellulose to achieve a high humification degree. Spearman correlation analysis indicated that Stappia of the Proteobacteria phylum, Ilumatobacter of the Actinomycetes phylum, and eleven genera of Ascomycota were the main HA producers. This study provides new ideas for bagasse treatment and recycling and realizing the comprehensive use of resources.

OsWRKY12 negatively regulates the drought-stress tolerance and secondary cell wall biosynthesis by targeting different downstream transcription factor genes in rice

With the increasing occurrence of global warming, drought is becoming a major constraint for plant growth and crop yield. Plant cell walls experience continuous changes during the growth, development, and in responding to stressful conditions. The plant WRKYs play pivotal roles in regulating the secondary cell wall (SCW) biosynthesis and helping plant defend against abiotic stresses. qRT-PCR evidence showed that OsWRKY12 was affected by drought and ABA treatments. Over-expression of OsWRKY12 decreased the drought tolerance of the rice transgenics at the germination stage and the seedling stage. The transcription levels of drought-stress-associated genes as well as those genes participating in the ABA biosynthesis and signaling were significantly different compared to the wild type (WT). Our results also showed that less lignin and cellulose were deposited in the OsWRKY12-overexpressors, and heterogenous expression of OsWRKY12 in atwrky12 could lower the increased lignin and cellulose contents, as well as the improved PEG-stress tolerance, to a similar level as the WT. qRT-PCR results indicated that the transcription levels of all the genes related to lignin and cellulose biosynthesis were significantly decreased in the rice transgenics than the WT. Further evidence from yeast one-hybrid assay and the dual-luciferase reporter system suggested that OsWRKY12 could bind to promoters of OsABI5 (the critical component of the ABA signaling pathway) and OsSWN3/OsSWN7 (the key positive regulators in the rice SCW thickening), and hence repressing their expression. In conclusion, OsWRKY12 mediates the crosstalk between SCW biosynthesis and plant stress tolerance by binding to the promoters of different downstream genes.

Simultaneous removal of ammonia nitrogen, phosphate, zinc, and phenol by degradation of cellulose in composite mycelial pellet bioreactor: Enhanced performance and community co-assembly mechanism

In this experiment, the prepared tea biochar-cellulose@LDH material (TB-CL@LDH) was combined with mycelium pellets to form the composite mycelial pellets (CMP), then assembled and immobilized with strains Pseudomonas sp. Y1 and Cupriavidus sp. ZY7 to construct a bioreactor. At the best operating parameters, the initial concentrations of phosphate (PO43--P), ammonia nitrogen (NH4+-N), chemical oxygen demand (COD), zinc (Zn2+), and phenol were 22.3, 25.0, 763.8, 1.0, and 1.0 mg L-1, the corresponding removal efficiencies were 80.4, 87.0, 83.4, 91.8, and 96.6%, respectively. Various characterization analyses demonstrated that the strain Y1 used the additional carbon source produced by the strain ZY7 degradation of cellulose to enhance the removal of composite pollutants and clarified the principle of Zn2+ and PO43--P removal by adsorption, co-precipitation and biomineralization. Pseudomonas and Cupriavidus were the dominant genera according to the high-throughput sequencing. As shown by KEGG results, nitrification and denitrification genes were affected by phenol. The study offers prospects for the simultaneous removal of complex pollutants consisting of NH4+-N, PO43--P, Zn2+, and phenol.

Contribution of Aerobic Cellulolytic Gut Bacteria to Cellulose Digestion in Fifteen Coastal Grapsoid Crabs Underpins Potential for Mineralization of Mangrove Production

Grapsoid crabs (Decapoda: Grapsoidea) inhabiting along the land-sea transition provided various amounts and quality of vascular plant carbon (e.g., fresh mangrove leaf, leaf litter, and mangrove-derived organic carbon) and perform differing levels of herbivory. Other than endogenous cellulase, symbiotic cellulolytic bacteria could also contribute to the crabs' vascular plant carbon assimilation and mineralization. In this study, we isolated culturable cellulolytic bacteria from three gut regions (i.e., stomach, midgut, and hindgut) of 15 species of grapsoid crabs that inhabit in various coastal habitats (i.e., land margin, mangrove forest, tidal flat, and subtidal area). Bacillus, which was isolated from 11 out of the 15 grapsoid crabs, was the most common genus of culturable prominently cellulolytic bacteria among the target species. Seventy to ninety nine percent of culturable cellulolytic bacteria were removed, and the endoglucanase activity of five species was significantly reduced by 14.4-27.7% after antibiotic treatment. These results suggest that cellulolytic bacteria play a role in assisting mangrove carbon utilization in coastal grapsoid crabs, especially those inhabiting mangrove, mudflat, and subtidal areas. The significantly higher abundance of cellulolytic bacteria and the generally higher hydrolytic capacity of the bacteria in mangrove crab species suggest that they receive more contribution from symbionts for mangrove carbon utilization, while semi-terrestrial crabs seem to depend little on symbiotic cellulase due to the lower abundances.

How Resilient is Wood Xylan to Enzymatic Degradation in a Matrix with Kraft Lignin?

Despite the potential of lignocellulose in manufacturing value-added chemicals and biofuels, its efficient biotechnological conversion by enzymatic hydrolysis still poses major challenges. The complex interplay between xylan, cellulose, and lignin in fibrous materials makes it difficult to assess underlying physico- and biochemical mechanisms. Here, we reduce the complexity of the system by creating matrices of cellulose, xylan, and lignin, which consists of a cellulose base layer and xylan/lignin domains. We follow enzymatic degradation using an endoxylanase by high-speed atomic force microscopy and surface plasmon resonance spectroscopy to obtain morphological and kinetic data. Fastest reaction kinetics were observed at low lignin contents, which were related to the different swelling capacities of xylan. We demonstrate that the complex processes taking place at the interfaces of lignin and xylan in the presence of enzymes can be monitored in real time, providing a future platform for observing phenomena relevant to fiber-based systems.

Artificial cellulosic leaf with adjustable enzymatic CO2 sequestration capability

Developing artificial leaves to address the environmental burden of CO2 is pivotal for advancing our Net Zero Future. In this study, we introduce EcoLeaf, an artificial leaf that closely mimics the characteristics of natural leaves. It harnesses visible light as its sole energy source and orchestrates the controlled expansion and contraction of stomata and the exchange of petiole materials to govern the rate of CO2 sequestration from the atmosphere. Furthermore, EcoLeaf has a cellulose composition and mechanical strength similar to those of natural leaves, allowing it to seamlessly integrate into the ecosystem during use and participate in natural degradation and nutrient cycling processes at the end of its life. We propose that the carbon sequestration pathway within EcoLeaf is adaptable and can serve as a versatile biomimetic platform for diverse biogenic carbon sequestration pathways in the future.

The orchestration of sustained drug delivery by bacterial cellulose/gelatin nanocomposites reinforced with carboxylic carbon nanotubes

Recently, modifying bacterial cellulose (BC) by compositing it with other nano-biomaterials has become inevitable to achieve its desired properties in drug delivery. To address this, our study endeavors to utilize an in-situ fabrication method for the creation of a multifunctional BC/gelatin (BC/Gel) platform reinforced with carboxylic multi-walled carbon nanotubes (cMWCNTs) as a sustainable delivery model of biomolecules. Incipiently, cMWCNTs were loaded with human serum albumin (HSA) as a drug model, with an optimized nanoparticle-to-protein ratio of 1:5 and loading efficiency of 90.0 ± 1.0 % before incorporation into BC/Gel hydrogels. By comparison, nanocomposition improved the surface area and overall porosity of BC/Gel up to 58.0 ± 1.3 m2/g and 85.5 ± 1.1 %, respectively. Likewise, significant wettability of 44.0 ± 0.1° and dramatic biodegradation rate of 36.9 ± 1.2 % were other exceptionally gained attributes. Meanwhile, with a Zero-order kinetic mechanism, CNT-HSA integration facilitated the controlled release of 56.0 ± 0.9 % HSA over 7 days. Drug-loaded nanocomposites showcased >70 % viability during in vitro cellular trials using Human Foreskin Fibroblasts (HFF). Overall, BC/Gel/CNT-HSA nanocomposite exhibited favorable cell behavior, devoid of cytotoxic manifestations. Consequently, this BC-based nanocomposite scaffold implicates the premiere capability in the sustained delivery of an extended range of protein biomolecules, offering a promising therapeutic avenue for bolstering tissue regeneration.

Bacterial synthase-dependent exopolysaccharide secretion: a focus on cellulose

Bacterial biofilms are a prevalent multicellular life form in which individual members can undergo significant functional differentiation and are typically embedded in a complex extracellular matrix of proteinaceous fimbriae, extracellular DNA, and exopolysaccharides (EPS). Bacteria have evolved at least four major mechanisms for EPS biosynthesis, of which the synthase-dependent systems for bacterial cellulose secretion (Bcs) represent not only key biofilm determinants in a wide array of environmental and host-associated microbes, but also an important model system for the studies of processive glycan polymerization, cyclic diguanylate (c-di-GMP)-dependent synthase regulation, and biotechnological polymer applications. The secreted cellulosic chains can be decorated with additional chemical groups or can pack with various degrees of crystallinity depending on dedicated enzymatic complexes and/or cytoskeletal scaffolds. Here, I review recent progress in our understanding of synthase-dependent EPS biogenesis with a focus on common and idiosyncratic molecular mechanisms across diverse cellulose secretion systems.

Cloning and functional mechanism of the dwarf gene gba affecting stem elongation and cellulose biosynthesis in jute (Corchorus olitorius)

Plant height (PH) is an important factor affecting bast fiber yield in jute. Here, we report the mechanism of dwarfism in the 'Guangbaai' (gba) of jute. The mutant gba had shorter internode length and cell length compared to the standard cultivar 'TaiZi 4' (TZ4). Exogenous GA3 treatment indicated that gba is a GA-insensitive dwarf mutant. Quantitative trait locus (QTL) analysis of three PH-related traits via a high-density genetic linkage map according to re-seq showed that a total of 25 QTLs were identified, including 13 QTLs for PH, with phenotypic variation explained ranging from 2.42 to 74.16%. Notably, the functional mechanism of the candidate gene CoGID1a, the gibberellic acid receptor, of the major locus qPHIL5 was evaluated by transgenic analysis and virus-induced gene silencing. A dwarf phenotype-related single nucleotide mutation in CoGID1a was identified in gba, which was also unique to the dwarf phenotype of gba among 57 cultivars. Cogid1a was unable to interact with the growth-repressor DELLA even in the presence of highly accumulated gibberellins in gba. Differentially expressed genes between transcriptomes of gba and TZ4 after GA3 treatment indicated up-regulation of genes involved in gibberellin and cellulose synthesis in gba. Interestingly, it was found that up-regulation of CoMYB46, a key transcription factor in the secondary cell wall, by the highly accumulated gibberellins in gba promoted the expression of cellulose synthase genes CoCesA4 and CoCesA7. These findings provide valuable insights into fiber development affected by endogenous gibberellin accumulation in plants.

The TRAPPIII subunit, Trs85, has a dual role in the trafficking of cellulose synthase complexes in Arabidopsis

Plant cell walls are essential for defining plant growth and development, providing structural support to the main body and responding to abiotic and biotic cues. Cellulose, the main structural polymer of plant cell walls, is synthesized at the plasma membrane by cellulose synthase complexes (CSCs). The construction and transport of CSCs to and from the plasma membrane is poorly understood but is known to rely on the coordinated activity of cellulose synthase-interactive protein 1 (CSI1), a key regulator of CSC trafficking. In this study, we found that Trs85, a TRAPPIII complex subunit, interacted with CSI1 in vitro. Using functional genetics and live-cell imaging, we have shown that trs85-1 mutants have reduced cellulose content, stimulated CSC delivery, an increased population of static CSCs and deficient clathrin-mediated endocytosis in the primary cell wall. Overall, our findings suggest that Trs85 has a dual role in the trafficking of CSCs, by negatively regulating the exocytosis and clathrin-mediated endocytosis of CSCs.

An experimental and modeling approach to describe the deactivation of cellulases at the air-liquid interface

Understanding the reaction mechanisms involved in the enzymatic hydrolysis of cellulose is important because it is kinetically the most limiting step of the bioethanol production process. The present work focuses on the enzymatic deactivation at the air-liquid interface, which is one of the aspects contributing to this global deactivation. This phenomenon has already been experimentally proven, but this is the first time that a model has been proposed to describe it. Experiments were performed by incubating Celluclast cocktail solutions on an orbital stirring system at different enzyme concentrations and different surface-to-volume ratios. A 5-day follow-up was carried out by measuring the global FPase activity of cellulases for each condition tested. The activity loss was proven to depend on both the air-liquid surface area and the enzyme concentration. Both observations suggest that the loss of activity takes place at the air-liquid surface, the total amount of enzymes varying with volume or enzyme concentration. Furthermore, tests performed using five individual enzymes purified from a Trichoderma reesei cocktail showed that the only cellulase that is deactivated at the air-liquid interface is cellobiohydrolase II. From the experimental data collected by varying the initial enzyme concentration and the ratio surface to volume, it was possible to develop, for the first time, a model that describes the loss of activity at the air-liquid interface for this configuration.

Young guard cells function dynamically despite low mechanical anisotropy but gain efficiency during stomatal maturation in Arabidopsis thaliana

Stomata are pores at the leaf surface that enable gas exchange and transpiration. The signaling pathways that regulate the differentiation of stomatal guard cells and the mechanisms of stomatal pore formation have been characterized in Arabidopsis thaliana. However, the process by which stomatal complexes develop after pore formation into fully mature complexes is poorly understood. We tracked the morphogenesis of young stomatal complexes over time to establish characteristic geometric milestones along the path of stomatal maturation. Using 3D-nanoindentation coupled with finite element modeling of young and mature stomata, we found that despite having thicker cell walls than young guard cells, mature guard cells are more energy efficient with respect to stomatal opening, potentially attributable to the increased mechanical anisotropy of their cell walls and smaller changes in turgor pressure between the closed and open states. Comparing geometric changes in young and mature guard cells of wild-type and cellulose-deficient plants revealed that although cellulose is required for normal stomatal maturation, mechanical anisotropy appears to be achieved by the collective influence of cellulose and additional wall components. Together, these data elucidate the dynamic geometric and biomechanical mechanisms underlying the development process of stomatal maturation.

Efficacious bioconversion of alginate/cellulose to value-added oligosaccharides by alginate-degrading GH5 endoglucanase from Trichoderma asperellum

Enzymatic degradation of lignocellulosic biomass provides an eco-friendly approach to produce value-added macromolecules, e.g., bioactive polysaccharides. A novel acidophilic GH5 β-1,4-endoglucanase (termed TaCel5) from Trichoderma asperellum ND-1 was efficiently expressed in Komagataella phaffii (∼1.5-fold increase, 38.42 U/mL). TaCel5 displayed both endoglucanase (486.3 U/mg) and alginate lyase (359.5 U/mg) enzyme activities. It had optimal pH 3.0 and strong pH stability (exceed 86 % activity retained over pH range 3.0-5.0). 80 % activity (both endoglucanase and alginate lyase) was retained in the presence of 15 % ethanol or 3.42 M NaCl. Analysis of action mode revealed that hydrolytic activity of TaCel5 required at least three glucose (cellotriose) residues, yielding mainly cellobiose. Glu241 and Glu352 are essential catalytic residues, while Asp106, Asp277 and Asp317 play auxiliary roles in cellulose degradation. TaCel5 displayed high hydrolysis efficiency for glucan and alginate substrates. ESI-MS analysis indicated that the enzymatic hydrolysates of alginate mainly contained disaccharides and heptasaccharides. This is the first detailed report of a bifunctional GH5 endoglucanase/alginate lyase enzyme from T. asperellum. Thus TaCel5 has strong potential in food and feed industries as a catalyst for bioconversion of cellulose- and alginate-containing waste materials into value-added products oligosaccharides, which was of great benefit both for the economy and environment.

Overproduction of bacterial cellulose from Acetobacter xylinum BPR2001 using food industries wastes

In this study, a cost-effective complex culture media containing molasses and corn steep liquor (CSL) was developed for the high production of bacterial cellulose (BC) by investigating the effect of four effective factors on BC production at three levels using Taguchi and combined methods. The predicted and actual values of BC production in optimal conditions by Taguchi and combined methods were 8.41 and 14.52 g/L, respectively. These results showed that the combined method was more suitable for predicting the optimal conditions in the optimization of BC production, the cost of developed culture medium was around 94% cost of HS medium preparation, molasses was the most effective factor in both experimental design methods, and initial pH adjustment had little impact on BC production. Then, the effect of inoculation conditions containing three factors of inoculation age, ethanol addition time, and agitation rate on the increase of BC production at three levels was investigated using the response surface methodology with the Box-Behnken design algorithm. Under the optimal conditions including inoculum age of 3 days, ethanol addition time of 10 days, and stirring speed of 100 rpm, the predicted and experimental results of BC production were 21.61 and 20.21 g/L, respectively. This is among the highest ever reported for BC production, which was achieved with a more cost-effective culture medium containing molasses and CSL.

Nutritional and antioxidant potential of Pleurotus djamor (Rumph. ex Fr.) Boedijn produced on agronomic wastes banana leaves and sugarcane bagasse substrates

Global food production faces challenges concerning access to nutritious and sustainably produced food. Pleurotus djamor, however, is an edible mushroom that can be cultivated on agricultural waste. Considering that nutritional and functional potential of mushrooms can change based on cultivation conditions, we examined the influence of substrates with different compositions of banana leaf and sugarcane bagasse on the nutritional, mycochemical, and antioxidant properties of P. djamor. The mushrooms were grown for 120 days and dried in a circulating air oven at 45 °C for three days. We conducted bromatological analyses and mycochemical characterization (1H-NMR, total phenolics, and flavonoids) of the mushrooms and assayed the antioxidant activity of extracts from the dried mushrooms using an ethanol/water solution (70:30 v/v). In general, the substrates produced mushrooms with high protein (18.77 ± 0.24% to 17.80 ± 0.34%) and dietary fiber content (18.02 ± 0.05% to 19.32 ± 0.39%), and with low lipid (0.28 + 0.08% to 0.4 + 0.6%), and caloric content (maximum value: 258.42 + 8.49), with no significant differences between the groups (p ≥ 0.05). The mushrooms also exhibited high levels of total phenolics and flavonoids. The mushrooms cultivated on sugarcane bagasse substrates presented the highest values (p < 0.05). Analysis of the 1H-NMR spectra indicates an abundant presence of heteropolysaccharides, β-glucans, α-glucans, and oligosaccharides, and all the mushroom extracts exhibited high antioxidant activity. In conclusion, our study demonstrates that agricultural residues permit sustainable production of edible mushrooms while maintaining nutritional and functional properties.

Synergistic analysis of lignin degrading bacterial consortium and its application in rice straw fiber film

Fiber film have received widespread attention due to its green friendliness. We can use microorganisms to degrade lignin in straw to obtain cellulose and make fiber films. Herein, a group of high-temperature (50 °C) lignin degrading bacterial consortium (LDH) was enriched and culture conditions for lignin degradation were optimized. Combined with high-throughput sequencing technology, the synergistic effect of LDH-composited bacteria was analyzed. Then LDH was used to treat rice straw for the bio-pulping experiment. The results showed that the lignin of rice straw was degraded 32.4 % by LDH at 50 °C for 10 d, and after the optimization of culture conditions, lignin degradation rate increased by 9.05 % (P < 0.001). The bacteria that compose in LDH can synergistically degrade lignin. Paenibacillus can encode all lignin-degrading enzymes present in the LDH. Preliminary tests of LDH in the pulping industry have been completed. This study is the first to use high temperature lignin degrading bacteria to fabricate fiber film.

Selective lignin arylation for biomass fractionation and benign bisphenols

Lignocellulose is mainly composed of hydrophobic lignin and hydrophilic polysaccharide polymers, contributing to an indispensable carbon resource for green biorefineries1,2. When chemically treated, lignin is compromised owing to detrimental intra- and intermolecular crosslinking that hampers downstream process3,4. The current valorization paradigms aim to avoid the formation of new C-C bonds, referred to as condensation, by blocking or stabilizing the vulnerable moieties of lignin5-7. Although there have been efforts to enhance biomass utilization through the incorporation of phenolic additives8,9, exploiting lignin's proclivity towards condensation remains unproven for valorizing both lignin and carbohydrates to high-value products. Here we leverage the proclivity by directing the C-C bond formation in a catalytic arylation pathway using lignin-derived phenols with high nucleophilicity. The selectively condensed lignin, isolated in near-quantitative yields while preserving its prominent cleavable β-ether units, can be unlocked in a tandem catalytic process involving aryl migration and transfer hydrogenation. Lignin in wood is thereby converted to benign bisphenols (34-48 wt%) that represent performance-advantaged replacements for their fossil-based counterparts. Delignified pulp from cellulose and xylose from xylan are co-produced for textile fibres and renewable chemicals. This condensation-driven strategy represents a key advancement complementary to other promising monophenol-oriented approaches targeting valuable platform chemicals and materials, thereby contributing to holistic biomass valorization.

Half of the 18O enrichment of leaf sucrose is conserved in leaf cellulose of a C3 grass across atmospheric humidity and CO2 levels

The 18O enrichment (Δ18O) of cellulose (Δ18OCel) is recognized as a unique archive of past climate and plant function. However, there is still uncertainty regarding the proportion of oxygen in cellulose (pex) that exchanges post-photosynthetically with medium water of cellulose synthesis. Particularly, recent research with C3 grasses demonstrated that the Δ18O of leaf sucrose (Δ18OSuc, the parent substrate for cellulose synthesis) can be much higher than predicted from daytime Δ18O of leaf water (Δ18OLW), which could alter conclusions on photosynthetic versus post-photosynthetic effects on Δ18OCel via pex. Here, we assessed pex in leaves of perennial ryegrass (Lolium perenne) grown at different atmospheric relative humidity (RH) and CO2 levels, by determinations of Δ18OCel in leaves, Δ18OLGDZW (the Δ18O of water in the leaf growth-and-differentiation zone) and both Δ18OSuc and Δ18OLW (adjusted for εbio, the biosynthetic fractionation between water and carbohydrates) as alternative proxies for the substrate for cellulose synthesis. Δ18OLGDZW was always close to irrigation water, and pex was similar (0.53 ± 0.02 SE) across environments when determinations were based on Δ18OSuc. Conversely, pex was erroneously and variably underestimated (range 0.02-0.44) when based on Δ18OLW. The photosynthetic signal fraction in Δ18OCel is much more constant than hitherto assumed, encouraging leaf physiological reconstructions.

Isolation and Enzymatic Characterization of Fungal Strains from Grapevines with Grapevine Trunk Diseases Symptoms in Central Mexico

Grapevine production is economically indispensable for the global wine industry. Currently, Mexico cultivates grapevines across approximately 28 500 hectares, ranking as the 26th largest producer worldwide. Given its significance, early detection of plant diseases' causal agents is crucial for preventing outbreaks. Consequently, our study aimed to identify fungal strains in grapevines exhibiting trunk disease symptoms and assess their enzymatic capabilities as indicators of their phytopathogenic potential. We collected plant cultivars, including Malbec, Shiraz, and Tempranillo, from Querétaro, Mexico. In the laboratory, we superficially removed the plant bark to prevent external contamination. Subsequently, the sample was superficially disinfected, and sawdust was generated from the symptomatic tissue. Cultivable fungal strains were isolated using aseptic techniques from the recovered sawdust. Colonies were grown on PDA and identified through a combination of microscopy and DNA-sequencing of the ITS and LSU nrDNA regions, coupled with a BLASTn search in the GenBank database. We evaluated the strains' qualitative ability to degrade cellulose, starch, and lignin using specific media and stains. Using culture morphology and DNA-sequencing, 13 species in seven genera were determined: Acremonium, Aspergillus, Cladosporium, Dydimella, Fusarium, Sarocladium, and Quambalaria. Some isolated strains were able to degrade cellulose or lignin, or starch. These results constitute the first report of these species community in the Americas. Using culture-dependent and DNA-sequencing tools allows the detection of fungal strains to continue monitoring for early prevention of the GTD.