Dark fermentation of ground wheat starch for bio-hydrogen production by fed-batch operation

摘要

Ground wheat solution was used for bio-hydrogen production by dark fermentation using heat-treated anaerobic sludge in a completely mixed fermenter operating in fed-batch mode. The feed wheat powder (WP) solution was fed to the anaerobic fermenter with a constant flow rate of 8.33 mL h~(-1) (200 mL d~(-1)). Cumulative hydrogen production, starch utilization and hydrogen yields were determined at three different WP loading rates corresponding to the feed WP concentrations of 10, 20 and 30 g IT1. The residual starch (substrate) concentration in the fermenter decreased with operation time while starch consumption was increasing. The highest cumulative hydrogen production (3600 mL), hydrogen yield (465 mL H_2 g~(-1) starch or 3.1 mol H_2 mol~(-1) glucose) and hydrogen production rate (864 mL H_2 d~(-1)) were obtained after 4 days of fed-batch operation with the 20 g L~(-1) feed WP concentration corresponding to a WP loading rate of 4 g WP d~(-1). Low feed WP concentrations (10 g L~(-1)) resulted in low hydrogen yields and rates due to substrate limitations. High feed WP concentrations (30 g L~(-1)) resulted in the formation of volatile fatty acids (VFAs) in high concentrations causing inhibition on the rate and yield of hydrogen production.