Fermentation of lactose and its constituent sugars by Escherichia coli WDHL: Impact on hydrogen production

► Fermentation of galactose yields mainly hydrogen and ethanol. ► Lactate is the main product of the fermentation of glucose. ► Galactose catabolism is slower than the glucose catabolism. ► Hydrogen yield from glucose and galactose were 0.3 and 1.12 mol H2/mol hexose, respectively.