FIG. 3.

(a) The growth of Pseudomonas sp. HerB with olivine as a source of energy. Incubation in Hungate tubes with 10 mL medium, 20 mM , 1 mL/L vitamin mix, pH 7, 1.6% O₂ at 30°C. In this experiment we compared growth with/without 10% w:v olivine sand and with/without 10 mM . I=Initial cell density (∼7.7·10² cells/mL). A=No olivine, no . B=with olivine, no . C=No olivine, with . D=with olivine, with . Cell counts are based on triplicates and were determined by microscopy after 7 days of incubation. Error bars are 1 SD from triplicates. (b) Evolution of the O₂ concentration in gas phase during the growth of Pseudomonas sp. HerB in a mineral medium with olivine (subtracted from an un-inoculated control). Incubations were in 140 mL serum bottles with 10 mL mineral medium, 10% w:v olivine sand, 20 mM , 1 mL/L vitamin mix, pH 7, and ∼1.1 bar initial pressure at 30°C. The error bars are 1 SD based on triplicate readings of one bottle.