Hydrogen gas production from continuous fermentation of glucose in a minimal medium with Clostridium butyricum LMG 1213t1

Abstract

Summary We investigated the formation of hydrogen gas by Clostridium butyricum strain LMG 1213t1 in a chemostat in glucose limitation. At pH 5.1 the fermentation did not reach a steady-state. Within the pH range 5.5 to 7.1 in the culture vessel, and at constant dilution rate D no marked change in product spectrum was found. The produced gas consisted of approximately 60% H 2 and 40% CO 2 . About 1.75 mol H 2 was produced per mol glucose consumed. Hydrogen gas production rate increased proportionally with dilution rate D. At the highest dilution rate investigated 21.7 mmol H 2 was produced per hour and per liter reactor. Slightly higher efficiencies of hydrogen gas formation were obtained with acetate or butyrate (sodium salts) in the inflow medium. Acetate and butyrate were produced in a ratio of approximately 1.8 to 3 in all conditions tested. With increasing dilution rate D and at constant pH, slightly less fatty acids and slightly more cell material were formed. Y glucose max and Y ATP max values were 28.56 and 12.30 g dry weight/mol glucose or ATP, respectively. No change in fermentation pattern was observed with increasing concentrations of acetate or butyrate (up to 102.7 mM and 77.2 mM respectively) in the inflow medium.