Improvement in H₂ production from Clostridium butyricum by co-culture with Sporolactobacillus vineae

Dark fermentation has emerged as a promising method for converting waste into biohydrogen, a clean and sustainable energy source. However, the interaction between biohydrogen production performance and its microbial community has not been investigated sufficiently. This study investigated the effect of S. vineae on hydrogen production using defined cultures. Co-cultures of Clostridium butyricum (C. butyricum) with Sporolactobacillus vineae (S. vineae) increased the hydrogen production from 1.57 to 1.84 mol H₂/mol glucose_added, whereas lactic acid production did not increase in comparison with single culture of C. butyricum. At all the examined co-culture conditions, C. butyricum occupied more than 90% of the microbial composition; therefore, the microbial community analysis alone could not explain the difference in hydrogen production according to S. vineae addition. PICRUSt analysis showed that co-culture with S. vineae enhanced the expression of genes relating lactate to butyrate and H₂ pathway, although S. vineae did not produce butyrate. Co-cultures of Clostridium sp. and Sporolactobacillus sp. could be beneficial for H₂ production from the viewpoint of acidogenic pathway regulation. This study is expected to contribute to the understanding of the synergistic mechanisms of both the strains to obtain optimal biohydrogen production.