Recombinant Escherichia coli was constructed for co-production of hydrogen and polyhydroxybutyrate
(PHB) due to its rapid growth and convenience of genetic manipulation. In particular, anaerobic
metabolic pathways dedicated to co-production of hydrogen and PHB were established due to the
advantages of directing fluxes away from toxic compounds such as formate and acetate to useful
products. Here, recombinant E. coli expressing hydrogenase 3 and/or acetyl-CoA synthetase showed
improved PHB and hydrogen production when grown with or without acetate as a carbon source. When
hydrogenase 3 was over-expressed, hydrogen yield was increased from 14 to 153 mmol H2/mol glucose
in a mineral salt (MS) medium with glucose as carbon source, accompanied by an increased PHB yield
from 0.55 to 5.34 mg PHB/g glucose in MS medium with glucose and acetate as carbon source.