Comparative genomic and secretomic characterisation of endophytic Bacillus velezensis LC1 producing bioethanol from bamboo lignocellulose

Abstract

Background: Compared to physical and chemical methods, microbial lignocellulosic degradation is a green process. Bacillus is an excellent organic matter degrader, and it has exhibited various abilities required for lignocellulose degradation, including the degradation of cellulose, hemicellulose and lignin. Several B. velezensis strains encode lignocellulosases. However, their usefulness based on their ability to transform biomass has not been appreciated. Genomic, comprehensive comparative genomic and secretomic analyses were used to clarify the lignocellulose-degrading potential of these bacteria, which is necessary for their future application.Results: In the present study, the complete genomes of 20 B. velezensis strains and an endophytic bacterium, B. velezensis LC1, were analysed to nd common and unique genes encoding carbohydrateactive enzymes (CAZymes) and evaluate their potentials to degrade lignocellulose. By comparative whole genomic and CAZyomic analyses of all 21 strains, we identi ed genes of lignocellulolytic enzymes with the potential to degrade cellulose (GH5, GH30, GH4, GH1, GH16 and GH32) and hemicellulose (GH43, GH30, GH51, GH26 and GH53). Further identi cation of the secretome of B. velezensis LC1 by liquid chromatography-tandem mass spectrometry (LC-MS/MS) con rmed that a considerable number of proteins in the culture medium are involved in lignocellulose degradation, including endoglucanase, hemicellulases, and other related proteins. Moreover, assays of the activities of several lignocellulolytic enzymes including endoglucanase, exoglucanase, β-glucosidase, xylanase, lignin peroxidase, laccase, and manganese peroxidase show that these enzymes are more active in bamboo powder compared to glucose substrates. After a 6-day treatment, the degradation e ciencies of cellulose, hemicellulose and lignin from bamboo powder were 59.90%, 75.44% and 23.41%, respectively. The hydrolysate was subjected to ethanol fermentation with Saccharomyces cerevisiae and Escherichia coli KO11, yielding 10.44 g/L ethanol after 96 h.Conclusions: These ndings indicate that Bacillus velezensis strains have the potential to degrade a range of polysaccharides in lignocellulosic biomass. One strain, B. velezensis LC1, e ciently degrades bamboo lignocellulose components, allowing for subsequent ethanol production.

Comparative genomic and transcriptome analysis of Bacillus velezensis CL-4 fermented corn germ meal

“…In addition, common genes from the GH11, GH43, GH51, and GH30 families participate in hemicellulose degradation including endo-β-1,4-xylanase, arabinoxylan arabinofuranohydrolase, arabinan endo-1,5-α-L-arabinosidase, 1,4-β-xylosidase, α-N-arabinofuranosidase, and glucuronoxylanase and are the key factors for xylan degradation. Hemicellulose, the second most abundant lignocellulose component, can be hydrolyzed to monosaccharides by a variety of enzymatic systems (Tang et al 2021 ). The catalytic site of endo-1,4-β-xylanase from the GH11 family is the β-1,4-xylosidic linkages of xylan, producing short xylooligosaccharides after xylan cleavage (Monica and Kapoor 2021 ).…”

Screening and genome-wide analysis of lignocellulose-degrading bacteria from humic soil

“…The examination of B. velezensis focused primarily on the improvement in enzyme production conditions. At present, the related research of B. velezensis mainly focuses on the screening of strains, the optimization of fermentation conditions ( Nair et al, 2018 ; Li F. et al, 2020 ; Djelid et al, 2022 ), and the prediction of lignocellulosic degradation function of strains by high-throughput sequencing technology and the mining of corresponding genes ( Chen et al, 2018 ; Tang et al, 2021 ). As a member of a class of microorganisms with cellulose degradation potential, the B. velezensis genome contains abundant carbohydrase genes.…”