Background: Bamboo, a lignocellulosic feedstock, is considered as a potentially excellent raw material and evaluated for lignocellulose degradation and bioethanol production, with a focus on using physical and chemical pre-treatment. However, studies reporting the biodegradation of bamboo lignocellulose using microbes such as bacteria and fungi are scarce. Results:In the present study, Bacillus velezensis LC1 was isolated from Cyrtotrachelus buqueti, in which the symbiotic bacteria exhibited lignocellulose degradation ability and cellulase activities. We performed genome sequencing of B. velezensis LC1, which has a 3929,782-bp ring chromosome and 46.5% GC content. The total gene length was 3,502,596 bp using gene prediction, and the GC contents were 47.29% and 40.04% in the gene and intergene regions, respectively. The genome contains 4018 coding DNA sequences, and all have been assigned predicted functions. Carbohydrate-active enzyme annotation identified 136 genes annotated to CAZy families, including GH, GTs, CEs, PLs, AAs and CBMs. Genes involved in lignocellulose degradation were identified. After a 6-day treatment, the bamboo shoot cellulose degradation efficiency reached 39.32%, and the hydrolysate was subjected to ethanol fermentation with Saccharomyces cerevisiae and Escherichia coli KO11, yielding 7.2 g/L of ethanol at 96 h. Conclusions:These findings provide an insight for B. velezensis strains in converting lignocellulose into ethanol. B. velezensis LC1, a symbiotic bacteria, can potentially degrade bamboo lignocellulose components and further transformation to ethanol, and expand the bamboo lignocellulosic bioethanol production.

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Plants have evolved constitutive and inductive defense mechanisms to protect themselves from herbivorous insects. Metabolites in plants are thought to be involved in response to herbivores. Bambusa emeiensis is an important bamboo species widely distributed in Southwest China. It is easy to attract herbivores such as Cyrtotrachelus buqueti. Through the detection and analysis of metabolites in B. emeiensis metabolomic data, 35 differential metabolites (biomarkers) were finally identified from 206 detection peaks, mainly primary metabolites. Subsequently, we conducted an association analysis between 35 biomarkers that annotated to be involved in 71 metabolic pathways in the metabolome and 324 differentially expressed genes (DEGs) in 207 gene expression pathways distributed in the transcriptome of B. emeiensis after feeding by C. buqueti. We also discussed the relationship between the changes in gene expression levels and metabolite content variation. A total of 47 integrated pathways containing the corresponding DEGs and biomarkers were screened out, with the amino acid synthesis pathway (ko01230) containing the most DEGs and biomarkers. In these integrated pathways, the changes in biomarkers content and the expression levels of the corresponding genes were generally consistent. For example, the increase in tryptophan content was accompanied by an increase in the expression of the corresponding catalase in the tryptophan synthesis pathway. Similar to this was glucose and trehalose in carbohydrate metabolism. Therefore, this study further deepened our understanding of the defense mechanism of B. emeiensis against bamboo pests and provided new insights for the prevention and control of bamboo diseases and pests.

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.

Neosinocalamus affinis, a type of cluster bamboo, is a good candidate feedstock for biomass energy. In this study, we identified 686 genes as members of CAZyme families in the N. affinis transcriptome. These genes included 222 glycoside hydrolases (GHs), 288 glycosyltransferases (GTs), 64 carbohydrate esterases (CEs), 70 auxiliary activities (AAs), 37 carbohydrate binding modules (CBMs) and five polysaccharide lyases (PLs). Expression profile analysis revealed that several CAZyme genes, particularly GT, GH, AA and CE family members, were up‐regulated after insect infestation. Lignocellulose assays showed that the contents of three components, namely, cellulose, hemicellulose and lignin, increased after insect infestation. CAZyme genes were abundant in the N. affinis transcriptome and were involved in herbivory response. These findings could be applied to the protection of bamboo against herbivores, such as the bamboo snout beetle Cyrtotrachelus buqueti, and in the development of low‐cost chemical feedstock from bamboo.