Greening Biorefineries: Enhancing Performance Through Photo-Fermentation Biohydrogen and Biomethane Co-Production

Abstract

Biohydrogen and biomethane co-production via photo-fermentation and anaerobic digestion would improve the energy conversion efficiency (ECE) by further utilizing organic matter remained in the liquid and slag of photo-fermentation biohydrogen production. In this study, the effect of connection time between photo-fermentation and anaerobic digestion on biohydrogen and biomethane production as well as bacterial community was evaluated. At 60 h of connection time, the hydrogen production and methane production were 256.56 mL and 1233.3 mL, respectively. The ECE increased from 3.72% for photo-fermentation hydrogen production to 53.49% for hydrogen and methane co-production. Analysis of the bacterial community showed that adding activated sludge compressed the growth space for photo-fermentation biohydrogen-producing bacteria. Connecting methane fermentation at 60 h can not only improve ECE but also further extend the economic value of the industry compared to the individual photo-fermentation biohydrogen production.

Keywords: Photo-fermentation biohydrogen, Biomethane, Hydrogen and methane co-production, Connection time