Dark-Fermentative Biological Hydrogen Production from Mixed Biowastes Using Defined Mixed Cultures.

Biological hydrogen (H2) production from the biowastes is widely recognized as a suitable alternative approach to utilize low cost feed instead of costly individual sugars. In the present investigation, pure and mixed biowastes were fermented by defined sets of mixed cultures for hydrolysis and H2 production. Under batch conditions, up to 65, 67 and 70 L H2/kg total solids (2%, TS) were evolved from apple pomace (AP), onion peels (OP) and potato peels (PP) using a combination of hydrolytic mixed culture (MHC5) and mixed microbial cultures (MMC4 or MMC6), respectively. Among the different combinations of mixed biowastes including AP, OP, PP and pea-shells, the combination of OP and PP exhibited maximum H2 production of 73 and 84 L/kg TS with MMC4 and MMC6, respectively. This study suggested that H2 production can be effectively regulated by using defined sets of mixed cultures for hydrolysis and H2 production from pure and mixed biowastes as feed even under unsterile conditions.