FIG 9.

H₂ production (A) and H₂ yield (B) of constructed R. sphaeroides strains after 240 h of photoheterotrophic growth with acetate and l-glutamate in the absence of NH₄Cl under an Ar atmosphere. Chromosomal genetic background of R. sphaeroides strains is indicated. Each bar is represented as follows: black bars, without plasmid; gray bars, pMGP as a vector control; white bars, pMGPaceBA for heterologous expression of aceBA, which is involved in the glyoxylate bypass. The molar amount of H₂ produced was calculated from the volume of H₂ produced based on the assumption that 1.00 ml of H₂ is equal to 40.9 μmol. H₂ yields from acetate and l-glutamate are represented as percentage of the theoretical maximal H₂ yield from acetate (4.00 mol H₂/mol) and l-glutamate (9.00 mol H₂/mol) consumed. Results of Student’s t test are indicated as follows: ns, no significant difference; *, P < 0.05; **, P < 0.01.