The performance of COD removal and hydrogen production in a single stage system from starch using the consortium PB-Z under simulated natural conditions

Abstract

A mixed bacterial community, which is defined as PB-Z in the study, could directly utilize a high concentration of starch and starchy residue to produce hydrogen. The aim of the work was to elucidate the possible mechanism of the single stage system, improve the performance of hydrogen production and COD removal, and evaluate the potential of its engineering application. The result of high-throughput sequencing showed that the consortium PB-Z was mainly composed of photosynthetic bacteria and hydrolytic/acidogenic bacteria. Therefore, starch could be used in a single stage system. Adding both Fe2+ and Ca2+ could significantly increase the maximum hydrogen production rate and cumulative hydrogen production by 168.8% and 70.7% compared with the control group (p < 0.05), respectively. Vitamin B was necessary for PB-Z to utilize acetic acid to produce hydrogen. The result of vitamin B effect on hydrogen production from starch showed that the cumulative hydrogen production and the COD removal efficiency increased from 1591 mL H2/L culture to 1831 mL H2/L culture and 38.9% to 56.4%, respectively. Compared with the continuous illumination, 12 h light/12 h dark cycle had no significant effect on cumulative hydrogen production, which makes the consortium PB-Z more attractive for engineering application.