Fig. 5.

Nitrite production (circles) and growth curves (triangles) of strains HCA1 (A), PS0 (B), and SCM1 (C) with 100 µM α-ketoglutaric acid (gray) relative to controls without organic carbon supplements (first transfer, white; second transfer, black). No second transfer is included in C, because SCM1 has the demonstrated capacity to sustain growth under strictly autotrophic conditions (23, 24). Error bars represent the SD of triplicate cultures (please note that, in most cases, the error bars are too small to be visible in the figure).