Fig 3.
Residual glycerol and concentrations of metabolites produced by microbial communities associated with cathodes that were (i) supplied −0.32 mA cm−2 (pre-OCP current), (ii) switched to OCP, (iii) maintained at OCP and then supplied hydrogen (OCP + H2), and finally (iv) resupplied −0.32 mA cm−2 (post-OCP current). Negligible concentrations of butanol, isobutyrate, isovalerate, and hexanoate are not shown. Significant differences (GLM) from OCP values are indicated for each compound as follows: P < 0.10, •; P < 0.05, *; P < 0.01, **; P < 0.001, ***.