Enhancement of Hydrogen Production through a Mixed Culture of Enterobacter cloacae and Rhodobacter sphaeroides

Abstract

Biohydrogen production is a hopeful approach to produce hydrogen (H2), which is considered as an alternative clean fuel in the future. In this work, a newly isolated strain YA012 was identified to be Enterobacter cloacae according to the 16S rRNA gene sequence analysis. This strain could generate about 1.5 mol of H2/mol of glucose under anaerobic conditions, and acetic acid, butyric acid, and ethanol were its main soluble metabolites. To improve H2 production, a mixed-culture system of E. cloacae YA012 and Rhodobacter sphaeroides HY01 was constructed and the influences of important factors on H2 production were researched. When the ratio of dark- to photofermentative bacteria (RDP), initial pH, phosphate buffer concentration (PBC), and light intensity were set at 1:600, 7.5, 50 mM, and 10 klux, respectively, the H2 production reached an optimum. The maximum H2 yield and maximum H2 evolution rate of this mixed culture were 3.96 mol of H2/mol of glucose and 105.6 ± 25.1 mL L–1 h–1, respectively. It is also ...