Monitoring lactic acid bacteria in anaerobic reactors producing biohydrogen from whey milk

Abstract

The use of microbial consortium for biohydrogen production by fermentative process allows combinations of metabolic pathways which facilitate the processing of several substrates. However, the yield of such process may be considered low due to the simultaneous production of by-products and, presence of competitor microorganisms which may inhibit the hydrogen-producer strains such as, Clostridium spp. It is widely known that some lactic acid bacteria (LABs) produce antimicrobial peptides namely bacteriocins and are part of the indigenous microbiota of several foods, and consequently, of the wastewater generated in food-processing facilities such as the whey-milk, which may be applied for biohydrogen production. Some evidences correlated the presence of lactic acid bacteria and/or their antimicrobial peptides with the reduction of hydrogen production by fermentative process. The main objective of the present project is to isolate and quantify lactic acid bacteria population by conventional culture techniques and by real-time PCR, as well as, to evaluate the effect of the BALs and their bacteriocins on the population dynamics of Clostridium spp., in bioreactors feed with whey-milk for biohydrogen production. Additionally, the antimicrobial activity of the bacteriocins will be evaluated in vitro against Clostridium spp.