Hydrogen production in dark fermentation of a brewery sludge pre-treated with white-rot fungi in submerged culture

Abstract

Numerous strategies integrating a white-rot fungi with other microbial fermentations have been explored, although little has been reported on the use of liquid residues like brewery waste slurries (BWS) for hydrogen production. The production of fungal biomass and hydrogen from BWS after a fungal pre-treatment (FT) and dark fermentation (DF) was evaluated. 31.2 ± 0.2 g/L of dry weight biomass of the strain Pleurotus ostreatus was recovered after 18 days of incubation. Chemical oxygen demand (COD) was reduced 76 %, while 78 % to 95 % removal of the recalcitrant coloured compounds in BWS was achieved. Hydrogen generation reached 495.7 ± 6.2 mL H2/g CODconsumed, with the process exhibiting 94.2 % of the theoretical molar yield. The combined FT/DF process degraded ~2 times more COD and showed a 25 % higher hydrogen yield than DF alone, demonstrating the potential of combining both systems with the aim of producing fungal biomass and hydrogen.