Potential of hydrogen production from sugarcane juice by Ethanoligenens harbinense Yuan-3

Inexpensive biomass is an ideal substrate for low-cost production of biohydrogen, but little was known about the biomass utilization performance of the ethanol-type hydrogen-producing bacteria Ethanoligenens harbinense. This study investigated the feasibility and performance of biohydrogen production by Ethanoligenens harbinense from sugarcane juice (SJ). Medium and process were firstly optimized with SJ as carbon source and the highest hydrogen yield was obtained when SJ was hydrolyzed by acid, and the medium contained 10 g/L sugar and 3 g/L yeast extract with pH at 6.0. Compared to batch fermentation, fed-batch fermentation with cell recycle showed significant improvement in hydrogen productivity and yield. The maximum productivity reached 5.22 mmol-H₂/L•h, 201.7% higher than that of the single batch (1.73 mmol-H₂/L•h). The highest H₂ yield was 2.23 mol-H₂/mol-hexose, 65.2% higher than that of single batch fermentation. Cell immobilization with the fibrous bed bioreactor (FBB) also improved hydrogen productivity to 2.6 times that of batch fermentation with free cells. This study demonstrated the feasibility of hydrogen production from SJ with Ethanoligens sp., and a great improvement in hydrogen production was obtained by recycling cells and immobilizing cells in a fibrous bed bioreactor.