Continuous hydrogen production by dark and photo co-fermentation using a tubular multi-cycle bio-reactor with Paulownia biomass

Abstract

Bio-hydrogen production from lignocellulosic biomass has shown significant potential for helping to meet future energy demand. In the present work, we have utilized the Paulownia lignocellulosic biomass as feedstock for hydrogen production which has great potential for sustainable supply over the year due to its high growth rate. A dark and photo co-fermentative mechanism was adopted in a newly proposed tubular multi-cycle bioreactor and a 30-day continuous hydrogen production trial was conducted in the reactor. The key factors such as hydraulic retention time and organic loading rate associated with hydrogen production and substrate degradation were regulated to optimize the bioprocess. Our experimental findings show that with increase in hydraulic retention time and organic loading rate, hydrogen yield decreases and increases respectively. We have observed hydrogen yield, hydrogen concentration and substrate conversion ratio of 0.54 L/h, 53.84%, and 89.93% at optimized parameters of hydraulic retention time of 40 h, OLR of 1.0 g/L h, and light–dark interval time of 1:4 respectively. Our experimental finds may help to further explore the hydrogen production potential from lignocellulosic biomass of Paulownia.