Table 1.

Growth and H2 production data for wild-type and mutant strains of R. sphaeroides fed various organic substratesa

StrainbOrganic substrate (concn in mM)Doubling time (h)Cellular H2 production rate (molecules of H2/s/cell)cTotal H2 production (ml H2/ml culture)
2.4.1 (wild type)Lactate (45.2)d5.4 ± 1.1(1.8 ± 0.3) × 1053.3 ± 0.5
Succinate (33.9)d6.3 ± 1.0(1.6 ± 0.3) × 1052.8 ± 0.3
Malate (33.9)6.8 ± 0.7(1.2 ± 0.3) × 1052.5 ± 0.1
Glucose (22.6)d7.5 ± 2.3(7.8 ± 2.4) × 1041.6 ± 0.3
Tartrate (33.9)7.7 ± 0.3(5.4 ± 0.3) × 1041.0 ± 0.2
Xylose (27.1)d9.0 ± 1.6(4.8 ± 2.2) × 1041.2 ± 0.5
Glycerol (45.2)d9.2 ± 1.8(2.9 ± 1.2) × 1040.70 ± 0.24
Succinate (33.9)e6.0 ± 0.3(1.4 ± 0.3) × 1052.8 ± 0.1
HupSLECDr1Succinate (33.9)NM(1.6 ± 0.2) × 1052.9 ± 0.2
CfxABSuccinate (33.9)NGNDND
Succinate (33.9)e6.3 ± 0.3(1.3 ± 0.4) × 1052.7 ± 0.4
NifHDKr1Lactate (45.2)PGNDND
Succinate (33.9)PGNDND
Glucose (22.6)7.8 ± 1.6NDND
Xylose (27.1)8.3 ± 2.1NDND
Glycerol (45.2)9.6 ± 1.4NDND
  • a All media contained glutamate as the sole nitrogen source (8.3 mM total). The concentrations of all organic substrates were adjusted to produce a constant concentration of carbon atoms (135.5 mM). Values are means ± standard deviations. NM, not measured; NG, no growth; ND, none detected; PG, poor growth (≤120 Klett units).

  • b Descriptions of strains are contained in Table S1 in the supplemental material.

  • c Calculated with the assumptions that 1 Klett unit is equal to 1 × 107 cells/ml for all strains (25) and that 1 ml of H2 is equal to 40.88 μmol (2.46 × 1019 molecules).

  • d Cultures from which global transcript abundances were measured.

  • e Culture also included 80 mM DMSO.