Improving cold-adaptability of mesophilic cellulase complex with a novel mushroom cellobiohydrolase for efficient low-temperature ensiling

Comparison of the Bacterial and Fungal Communities and Metabolic Functions of Cottonseed Hull Waste Compost Associated with High and Low Yields of Straw Mushroom Volvariella volvacea

Volvariella volvacea was grown on cottonseed hull waste compost and divided into high-yield (HBE) and low-yield (LBE) conditions. Gene sequencing was used to examine bacterial and fungal populations during cottonseed husk waste composting. At the end of fermentation, the dominant bacterial genera in the HBE compost were Chelatococcus and Thermobacillus, while Symbiobacterium and Acinetobacter were more abundant in the LBE compost. Ascomycota and Basidiomycota dominated all the composting phases. The Ascomycota genera Colletotrichum, Pichia, Mycothermus, and Thermomyces dominated in phase II of HBE composting. The LBE compost had higher abundances of the Basidiomycota genera Cystofilobasidium and Cryptococcus than the HBE compost. The predicted pathotroph and saprotroph-symbiotroph abundances were more positively linked to HBE composting phase II than to LBE composting. High-biological-efficiency microbial communities are characterized by high pH, carbon, and nitrogen levels. Changes in physiochemical traits, microbial diversity, and metabolism affect the V. volvacea yield.

Upgraded cellulose and xylan digestions for synergistic enhancements of biomass enzymatic saccharification and bioethanol conversion using engineered Trichoderma reesei strains overproducing mushroom LeGH7 enzyme

Crop straws provide enormous lignocellulose resources transformable for sustainable biofuels and valuable bioproducts. However, lignocellulose recalcitrance basically restricts essential biomass enzymatic saccharification at large scale. In this study, the mushroom-derived cellobiohydrolase (LeGH7) was introduced into Trichoderma reesei (Rut-C30) to generate two desirable strains, namely GH7-5 and GH7-6. Compared to the Rut-C30 strain, both engineered strains exhibited significantly enhanced enzymatic activities, with β-glucosidases, endocellulases, cellobiohydrolases, and xylanase activities increasing by 113 %, 140 %, 241 %, and 196 %, respectively. By performing steam explosion and mild alkali pretreatments with mature straws of five bioenergy crops, diverse lignocellulose substrates were effectively digested by the crude enzymes secreted from the engineered strains, leading to the high-yield hexoses released for bioethanol production. Notably, the LeGH7 enzyme purified from engineered strain enabled to act as multiple cellulases and xylanase at higher activities, interpreting how synergistic enhancement of enzymatic saccharification was achieved for distinct lignocellulose substrates in major bioenergy crops. Therefore, this study has identified a novel enzyme that is active for simultaneous hydrolyses of cellulose and xylan, providing an applicable strategy for high biomass enzymatic saccharification and bioethanol conversion in bioenergy crops.

Current Advances in the Functional Genes of Edible and Medicinal Fungi: Research Techniques, Functional Analysis, and Prospects

Functional genes encode various biological functions required for the life activities of organisms. By analyzing the functional genes of edible and medicinal fungi, varieties of edible and medicinal fungi can be improved to enhance their agronomic traits, growth rates, and ability to withstand adversity, thereby increasing yield and quality and promoting industrial development. With the rapid development of functional gene research technology and the publication of many whole-genome sequences of edible and medicinal fungi, genes related to important biological traits have been mined, located, and functionally analyzed. This paper summarizes the advantages and disadvantages of different functional gene research techniques and application examples for edible and medicinal fungi; systematically reviews the research progress of functional genes of edible and medicinal fungi in biological processes such as mating type, mycelium and fruit growth and development, substrate utilization and nutrient transport, environmental response, and the synthesis and regulation of important active substances; and proposes future research directions for functional gene research for edible and medicinal fungi. The overall aim of this study was to provide a valuable reference for further promoting the molecular breeding of edible and medicinal fungi with high yield and quality and to promote the wide application of edible and medicinal fungi products in food, medicine, and industry.

Synthetic biology enables mushrooms to meet emerging sustainable challenges

With the increasing sustainability challenges, synthetic biology is offering new possibilities for addressing the emerging problems through the cultivation and fermentation of mushrooms. In this perspective, we aim to provide an overview on the research and applications mushroom synthetic biology, emphasizing the need for increased attention and inclusion of this rapidly advancing field in future mushroom technology over China and other countries. By leveraging synthetic biology, mushrooms are expected to play a more versatile role in various area, including traditional fields like circular economy, human wellness and pharmaceutics, as well as emerging fields like vegan meat, mushroom-based materials and pollution abatement. We are confident that these efforts using synthetic biology strategies have the potential to strengthen our capacity to effectively address sustainable challenges, leading to the development of a more sustainable social economy and ecology.

Structural insights into the oligomeric effects on catalytic activity of a decameric feruloyl esterase and its application in ferulic acid production

Oligomeric feruloyl esterase (FAE) has great application prospect in industry due to its potentially high stability and fine-tuned activity. However, the relationship between catalytic capability and oligomeric structure remains undetermined. Here we identified and characterized a novel, cold-adapted FAE (BtFae) derived from Bacteroides thetaiotaomicron. Structural studies unraveled that BtFae adopts a barrel-like decameric architecture unique in esterase families. By disrupting the interface, the monomeric variant exhibited significantly reduced catalytic activity and stability toward methyl ferulate, potentially due to its impact on the flexibility of the catalytic triad. Additionally, our results also showed that the monomerization of BtFae severely decreased the ferulic acid release from de-starched wheat bran and insoluble wheat arabinoxylan by 75 % and 80 %, respectively. Collectively, this study revealed novel connections between oligomerization and FAE catalytic function, which will benefit for further protein engineering of FAEs at the quaternary structure level for improved industrial applications.