Isolation of Cellulose-Degrading Bacteria from Cenchrus fungigraminus and Their Effects on Silage Quality

Cenchrus fungigraminus is a high-yielding forage material, but due to its relatively high lignin content and low carbohydrate content, its current feed utilization primarily relies on silage methods. However, current research on C. fungigraminus silage faces challenges such as unclear fermentation strains and low fiber degradation efficiency of traditional commercial starters, which prevent them from meeting the requirements for C. fungigraminus silage production. So, this study aimed to evaluate the fiber degradation effects of Bacillus velezensis JC2 (isolated from C. fungigraminus), the commercial cellulose-degrading bacterium Bacillus velezensis (CBV), and Trichoderma longibrachiatum (CTL) on C. fungigraminus. The degradation performance of JC2 was assessed based on the lignocellulose content of silage samples, scanning electron microscopy observations, crystallinity, and changes in chemical bonds and functional groups. Furthermore, the three strains exhibiting the highest activities of CMCase, FPase, and β-glucosidase during the screening process were combined with enzyme preparations to develop a specialized silage additive suitable for C. fungigraminus. The results indicate that: (1) Compared to commercial cellulose-degrading strains, after 14 days of fermentation with JC2 treatment, the lignin in C. fungigraminus was effectively degraded. (2) The silage feed of C. fungigraminus treated with a mixture of JC2, JC3, and JC28 showed significant improvements in sensory evaluation, lactic acid content, and cellulose degradation rate. The pH value decreased rapidly (<4.2), while the LA content and the LA/AA ratio increased, and the NDF content decreased by 4.2% DM, effectively enhancing the quality of the silage feed. In summary, the Bacillus velezensis JC2 selected in this experiment effectively degraded the fiber structure of C. fungigraminus, improved the quality of the silage, and enhanced its nutritional value, demonstrating significant potential as a specialized silage additive for C. fungigraminus.