Integrated Transcriptomic and Proteomic Analysis of a New Rumen-derived Bacillus licheniformis Strain for Regulating Microenvironments Treated with Different Carbon Sources

Bacillus licheniformis (B. licheniformis) is a microorganism with a wide range of probiotic properties and applications. Isolation and identification of novel strains is a major aspect of microbial research. In addition, the roles of different carbon sources affect B. licheniformis in regulating the microenvironment, and the mechanisms need to be further investigated. In this study, we first isolated and identified a new strain of B. licheniformis from bovine rumen fluid. Microcrystalline cellulose (MC) and cellobiose (CB) were used as carbon sources to treat the strain. Furthermore, a combination of transcriptomic and proteomic analyses was used to determine the effects of different carbon sources. The results showed that B. licheniformis ABC transporter proteins, antibiotic synthesis, flagellar assembly, cellulase-related pathways and proteins were significantly upregulated in the MC treatment compared to the CB treatment, and lactate metabolism was inhibited. In addition, MC was used as a carbon source to improve the bacterial inhibition of B. licheniformis and its own disease resistance and to regulate the rumen microenvironment. In conclusion, our research provides a potential new probiotic for feed research and a theoretical basis for investigating the mechanisms by which bacteria respond to different carbon sources.