dark fermentation

pha production

acid production

fermented

hydrogen yield

fermentation broth

volatile fatty

starter cultures

cells grown

Bioresource Technology

This study aimed to better understand the role of different microbial groups and the determining fermentation pathways in a biohydrogen (bioH2)-producing reactor fed with sugarcane vinasse by using next-generation sequencing and principal component analysis (PCA). Both microbial structure and dynamics were characterized. The highest bioH2 production levels were associated with the Thermoanaerobacterium genus, whilst lactate-producing bacteria comprised the dominant genera (e.g. Lactobacillus and Leuconostoc) within the reactor at both stable and unstable bioH2-producing periods. PCA further revealed that the fermentation of lactate played a dual role in the reactor, as both bioH2-producing (acetate + lactate → butyrate + bioH2) and non-bioH2-producing (lactate → propionate + acetate) routes could be observed. Overall, the results suggested that lactate is the primary alternative carbon source in vinasse-fed systems subjected to carbohydrate-shortage conditions.

Temporal dynamics and metabolic correlation between lactate-producing and hydrogen-producing bacteria in sugarcane vinasse dark fermentation: The key role of lactate