lactic and butyrate production in dark fermentation
The relevant factor for conversion of lactate and acetate to butyrate in the presence of carbohydrates is pH and the balance between Lactic acid bacteria, LAB (especially Lactobacillus), acetate producers (Bifidobacterium) and butyrate producers (mainly Clostridium) as well Prevotella. Microbial communities dominated by LAB are unable to produce butyrate. Low pH and high ethanol concentration might be the signalling factors responsible for metabolic shift of the dark fermentation microbial communities towards lactate fermentation.