Cellulase with Bacillus velezensis improves physicochemical characteristics, microbiota and metabolites of corn germ meal during two-stage co-fermentation

In this study, we investigated the processing effect of cellulase synergized withBacillus velezensis on the nutritional value of pretreated CGM (PCGM) in two-stage solid-state fermentation (SSF). High-throughput sequencing technology was used to explore the dynamic changes in microbial diversity. The results showed that compared with four combinations ofB. velezensis + Lactiplantibacillus plantarum (PCGM-BL), cellulase  + L. plantarum (PCGM-CL),control group (PCGM-CK), and cellulase  + B. velezensis + L. plantarum (PCGM-BCL), the fourth combination of PCGM-BCL significantly improved the nutritional characteristics of PCGM. After two-stage SSF (48  h), viable bacterial count and contents of crude protein (CP) and trichloroacetic acid-soluble protein (TCA-SP) all were increased in PCGM-BCL (p <  0.05), while the pH was reduced to 4.38 ± 0.02. In addition, compared with PCGM-BL, the cellulose degradation rate increased from 5.02 to 50.74%, increasing the amounts of short-chain fatty acids (216.61 ± 2.74 to 1727.55 ± 23.00 µg/g) and total amino acids (18.60 to 21.02%) in P CGM-BCL. Furthermore, high-throughput sequencing analysis revealed significant dynamic changes in microbial diversity. In the first stage of PCGM-BCL fermentation,Bacillus was the dominant genus (99.87%), which after 24  h of anaerobic fermentation changed tolactobacillus (37.45%). Kyoto Encylopaedia of Genes and Genomes (KEGG) metabolic pathway analysis revealed that t...
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research