Enhancing hydrogen production from winery wastewater through fermentative microbial culture selection

The present paper aims at enhancing the fermentative/co-fermentative hydrogen production from winery wastewater. Winery wastewater is a very abundant waste stream, with a high hydrogen production potential. On the other hand, it might exert toxic effects towards many hydrogen-producing bacteria. To optimize the process, a mixed microbial consortium was subject to microbial analysis to identify hydrogen-producing strains. These latter were isolated to obtain several pure cultures, either dark-fermentative, or photo-fermentative. Comparative fermentation tests were performed, using the isolated pure cultures, the initial mixed culture and a co-culture consisting of the two most performant dark fermentative and photo fermentative strains (i.e. Klebsiella pneumoniae strain MF101 and Rhodopseudomonas sp. strain BR0Y6). Results show that the initial mixed culture led to the highest production of 290 NmLH2 L-1. Further analyses on metabolic intermediates demonstrate the importance of synergies established in open fermentations to enhance the conversion of complex organic substrates to hydrogen.