Characteristics of hydrogen production and substrate consumption of Rhodopseudomonas palustris CQK 01 in an immobilized-cell photobioreactor

Effects of operation parameters on hydrogen production rate, substrate utilization efficiency and hydrogen bioconversion yield were investigated in a photobioreactor packed with sodium alginate/polyvinyl alcohol-124/carrageenan granules containing Rhodopseudomonas palustris CQK 01. Results demonstrate that an increase in influent glucose concentration and flow rate enhanced glucose transport from the bulk liquid into the granules, resulting in high hydrogen production. The bacteria mainly utilized the photo-heterotrophic pathway under optimal light illumination and produced hydrogen at low influent substrate loading, while they produced organic acids at high influent loading. The optimal temperature and pH of the influent medium for hydrogen production were independent of the illumination wavelength. The maximal hydrogen production rate of 2.61 mmol/L/h was achieved under illumination at 590 nm and 6000 lx, a substrate concentration of 60 mmol/L, a temperature of 30 °C and a pH 7 of the influent medium.