Construction of Synthetic Microbial Community for Straw Degradation Based on Multi-Omics Integration Technology and Elucidation of the Degradation Mechanism

The comprehensive utilization of lignocellulose is still constrained by the inefficiency of its degradation. The application of a synthetic microbial community represents a promising strategy to promote straw decomposition. By employing multi-omics coupling techniques to explore the microbial community and functional composition of various straw-associated environments, we identified core microbial taxa driving straw decomposition and subsequently constructed three microbial communities: a bacterial community, a fungal community, and a cross-kingdom community. In particular, the bacterial community exhibited intrinsic synergistic effects, increasing its straw weight loss by 10.8–57.3% compared to single-constituent strains. Liquid fermentation experiments further verified that the bacterial community possessed excellent straw degradation performance, achieving net degradation rates of 26.4% within 3 days and 33.7% within 30 days under 1% (w/v) tobacco straw conditions. The bacterial community exhibited cellulolytic and ligninolytic enzyme activities. Metagenomic analysis revealed that the bacterial community was dominated by Paenibacillus (42.3–70.9%), followed by Paenarthrobacter (7.1–31.7%) and Microbacterium (6.5–26.2%). CAZy annotation revealed that the bacterial community harbored numerous lignocellulose-degrading genes, including those encoding glycoside hydrolases (GHs, 51.2%), carbohydrate esterases (CEs, 17.7%), and auxiliary activities (AAs, 5.7%). Non-targeted metabolomics analysis identified 1024 differentially expressed metabolites that were involved in alanine, aspartate, and glutamate metabolism; butanoate metabolism; and cofactor biosynthesis. These results indicate that a community constructed with multi-omics coupling techniques can effectively degrade lignocellulose, which provides meaningful guidance for constructing synthetic microbial consortia aimed at lignocellulose decomposition.