Potential of Bacillus subtilis as oxygen-removal agent for biohydrogen production by Clostridium acetobutylicum

Abstract

Molasses are a source of fermentable sugars, the substrate utilized for this study, as it is a subproduct from sugarcane processing for sucrose recovery. These sugars can be metabolized for bioH2 production by bacterial strains, particularly strict-anaerobe Clostridium acetobutylicum (Clac) and its media preparation requires chemical of O2 removal and N2 flushing to promote anaerobiosis. Bacillus subtilis (Bsub) can deplete O2 from culture media and promotes anaerobiosis, which is an aspect that would benefit from further research. Clac was grown in an anaerobic medium and produced 269 mL of hydrogen at 72 h. By co-culturing Clac and Bsub, 502 mL of bioH2 were produced in a cysteine/N2 flushed medium, while 203 mL of bioH2 at 72 h were produced by aerobic co-culture. Additionally, in an untreated/aerobic conventional growth culture for Clac, no production of H2 was detected, reinforcing the utility of Bsub for anaerobiosis generation.