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 H-2 production by purple non sulfur bacterium Rhodobacter sphaeroides strains A 10 and D 3 Both strains produced H-2 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 H-2 Both strains were unable to produce H-2 in the presence of asparagine or glycine as nitrogen sources N N' dicyclohexylcarbodiimide the F0F1 ATPase inhibitor led to marked inhibition of H-2 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 H-2 production rate (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved