Substrate consumption rates for hydrogen production by Rhodobacter sphaeroides in a column photobioreactor

The effect of L-malic acid and sodium glutamate, which serve as the carbon and nitrogen source, respectively, on hydrogen production by Rhodobacter sp haeroides O.U.001 has been investigated in a batch water jacketed glass col umn photobioreactor (PBR), which has an inner volume of 400 ml. The PER was operated at different carbon to nitrogen ratios at 32 degrees C with a tun gsten lamp at a light intensity of 200 W m(-2). Carbon to nitrogen ratio wa s found to be an important parameter for bio-hydrogen production. Moreover, hydrogen gas production was dependent on certain threshold concentrations of sodium glutamate. L-malic acid consumption was found to be first order w ith respect to L-malic acid concentration, whereas sodium glutamate consump tion was found to be second order with respect to glutamate concentration. It was concluded that there is a close relationship between the hydrogen pr oduction rate and substrate consumption rates. A kinetic model is developed , which relates hydrogen gas production per amount of biomass, L-malic acid , and sodium glutamate concentrations. (C) 1999 Elsevier Science B.V. All r ights reserved.