Straw degradation: multiomics analysis of the efficient cellulose degradation mechanism of Bacillus velezensis LU4

Microbial degradation of agricultural residues offers a sustainable approach for straw management, yet comprehensive characterization of bacterial cellulose degradation mechanisms remains limited. We isolated Bacillus velezensis LU4 from humus soil, exhibiting cellulolytic enzyme activities: FPase 109.82 ± 7.94 U/mL, CMCase 80.13 ± 0.60 U/mL, and β-glucosidase 67.36 ± 0.45 U/mL, with environmental tolerance across pH 3.0–9.0, temperatures up to 70°C, and 4% NaCl. Whole genome sequencing revealed a 3.93 Mb genome enriched in CAZyme encoding genes (GH1, GH3, GH51 families) and a functionally coherent 9-gene maltose/maltodextrin utilization operon. Comparative genomic analysis against four reference strains identified selective 12% enrichment in starch/sucrose metabolism, while central carbon pathways remained conserved. Under cellulose induction, 2352 genes were differentially expressed; key upregulated genes included the cellobiose transporter celB and the multifunctional hydrolases nagZ , cotA , and abfA . Metabolomic profiling corroborated active glycolytic flux, as evidenced by elevated 3-phosphoglycerate and depleted acetyl coenzyme A pools. In sterilized soil microcosms, LU4 achieved 51.4% straw degradation over 50 d vs 34.5% in controls, with enhanced release of available nitrogen (87.56 vs. 34.32 mg/kg). This study provides a correlative multiomics framework for understanding LU4’s cellulolytic strategies and establishes a foundation for developing high performance microbial inoculants to accelerate straw degradation and improve soil fertility in sustainable agriculture. • Multiomics reveal cellulose degradation strategy in Bacillus velezensis LU4. • Glycolysis–TCA divergent regulation enhances cellulolytic efficiency. • LU4 achieves 51.4% straw degradation with enhanced soil N, P, K release.