Potential of perennial sorghum for biogas production: Pretreatment with yeast-contained inoculants during anaerobic storage

To investigate the behind mechanism on microbial roles during anaerobic storage of forages for biogas production, inoculants with different ratios of exogenous Lactiplantibacillus plantarum and Saccharomyces cerevisiae were applied during anerobic storage of perennial sorghum. Yeast-contained inoculants increased biogas production of perennial sorghum by 3.81-11.70%. When the proportion of yeast in microbial inoculant increased, the lactic, acetic and butyric acid contents significantly increased (P < 0.01) across the anaerobic storage. Species of Levilactobacillus brevis was the dominant bacteria, while the growth of some pernicious fungi such as Candia and Hannaella were restricted in samples. An equal appliance of lactic acid bacteria and yeast reduced relative abundances of Weissella cibaria and L. plantarum and increased relative abundance of L. brevis of perennial sorghum. In conclusion, the appropriate inclusion of yeasts in the pretreatment process of perennial sorghum can effectively improve the pretreatment efficacy and thus increase the biogas production.

Automated summary

This study aimed to investigate the mechanism of microbial roles during anaerobic storage of forages for biogas production. The results showed that the use of yeast-contained inoculants increased biogas production in perennial sorghum. As the proportion of yeast in the inoculant increased, the content of organic acids significantly increased. Additionally, the equal application of yeast and lactic acid bacteria altered the relative abundance of microorganisms and inhibited the growth of some harmful fungi.