Growth characteristics and hydrogen production by Rhodobacter sphaeroides using various amino acids as nitrogen sources and their combinations with carbon sources

Some amino acids (alanine, asparagine, glutamate, glycine, proline, and tyrosine) were used as nitrogen sources in combination with carbon sources (succinate and malate) to study growth properties and H2 production by purple non-sulfur bacterium Rhodobacter sphaeroides strains A-10 and D-3. Both strains produced H2 in succinate–glutamate and malate–glutamate media. Succinate was a better carbon source than malate. In comparison with strain D-3, strain A-10 was able to utilize proline, alanine or tyrosine as nitrogen sources in succinate medium and to produce H2. Both strains were unable to produce H2 in the presence of asparagine or glycine as nitrogen sources. N,N′-dicyclohexylcarbodiimide, the F0F1-ATPase inhibitor, led to marked inhibition of H2 production activity of R. sphaeroides. The results suggest that the R. sphaeroides cells growth can be achieved by the use of a large diversity of substrates but only some of them can increase the H2 production rate.