2.9 Fe0-corrosion test
The Fe0-corrosion activities of Prolixibacterstrains were tested in corrosion-test medium consisting of Sw medium supplemented with 100 mM HEPES buffer (pH 7.0), 10 mM nitrate, and 0.05% (wt/vol) yeast extract. Twenty milliliters of this medium was added anaerobically to a 50-ml serum bottle containing a foil of Fe0 (purity > 99.99%, 10 × 10 × 0.1 mm; Sigma-Aldrich), SS400 carbon steel (10 × 10 × 2 mm; Nippon Steel Stainless Corp.), or SUS316L stainless steel (10 × 10 × 2 mm; Nippon Steel Corp.). Air was removed from the medium by flushing with N2:CO2 (4:1), and the bottle was sealed with a butyl rubber stopper (Nichiden-Rika Glass). Subsequently, 0.2 ml of a bacterial preculture was added to the medium, and the culture was incubated at 25°C for 30 days.