Evaluation of hydrogen production by Clostridium strains on beet molasses

Abstract

Clostridium acetobutylicum DSM 792, C. acetobutylicum DSM 1731 and two newly isolated bacteria defined as the members of genus Clostridium - based on the 16S rRNA analysis and biochemical traits - were characterized with regard to their hydrogen production in media containing increasing beet molasses concentrations. The highest hydrogen yield was observed for C. acetobutylicum DSM 792 with a yield of 2.8 mol H-2 mol(-1) hexose in medium including 60 g L-1 molasses. This bacterium also produced the maximum amount of hydrogen (5908.8 mL L-1) at the same molasses concentration. A slightly lower hydrogen yield was measured for C. acetobutylicum DSM 1731 (2.5 mol H-2 mol(-1) hexose) when grown on 40 g L-1 molasses. The new isolates Clostridium roseum C and Clostridium saccharoperbutylacetonicum PF produced hydrogen with yields of 2.0 mol H-2 mol(-1) hexose at 40 and 60 g L-1 molasses and 2.1 mol H-2 mol(-1) hexose at 40 g L-1 molasses, respectively.