Table 1 Comparison of conversion and respiration rates of M. fumariolicum SolV cells from the CH4 chemostat (non-adapted cells) and the dual H2S-CH4 chemostat (sulfide-adapted cells)

From: Simultaneous sulfide and methane oxidation by an extremophile

 

non-adapted cells

sulfide-adapted cells

Conversion rates in the chemostat a

CH4 conversion

39

38

H2S conversion

–

42

Max. H2S conversion (at <0.15 μM H2S and 1.7 μM O2)

–

156

Maximum conversion rates in the MIMS chamber b

CH4 conversion

200 ± 11

133 ± 9

H2 conversion

78 – 104

60 – 82

H2S conversion (at 5–30 μM H2S and <10 μM O2)

22 ± 4

120 ± 13

H2S conversion (at 5–30 μM H2S and 60–80 μM O2)

–

132 – 154

Maximum respiration rates in the MIMS chamber b

CH4 respiration c

302 ± 9

211 ± 11

CH3OH respiration

311 ± 22

211 ± 13

H2 respiration

29 – 36

18 – 31

H2S respiration (at 40–80 μM H2S and <10 μM O2)

10 ± 1

53 ± 4

H2S respiration (at 30–80 μM H2S and 70–90 μM O2)

14 ± 1

77 ± 4

  1. aMeasured using GC and calculated from the differences between the gas inlet and gas outlet of the chemostat.
  2. bMeasured through membrane inlet mass-spectrometry (MIMS) and a fiber-optic oxygen sensor spot.
  3. cThis rate includes the theoretical 1 mol O2 needed to activate 1 mol CH4.
  4. All rates are in μmol · min−1 · g DW−1. All CH4, CH3OH and H2 conversion and respiration rates measured in the MIMS chamber were determined in the absence of H2S. Respiration refers to O2 consumption in response to addition of the listed substrates.
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