Figure 3. Growth of Methanomassiliicoccus luminyensis strain B10 on trimethylamine (TMA) and hydrogen (H2). (A) The growth of M. luminyensis B10 on methanol (M, 50 mM) and H2 (previously described by Dridi et al.18) was used as a positive control for growth and maximal cell density. (B) We now show that M. luminyensis B10 also grows on TMA (15 mM) in the presence of H2 (filled diamonds) but not on TMA in the absence of H2 (open diamonds). Accordingly, TMA is depleted in presence of H2 (filled triangles) and not in the absence of H2 (open triangles). The composition of the gas phase was measured at the end of the experiment (C) and revealed the production of methane (CH4) and the depletion of H2 in presence of either M or TMA. No CH4 was produced in the absence of H2 and CH4 was not produced nor H2 depleted in the absence of the methylated compound substrate (M or TMA). M. luminyensis B10 was obtained from DSMZ (DSM No. 25720) and cultivated in DSMZ medium 119, with rumen fluid replacing the sludge fluid. When H2 was present, initial atmosphere composition was: N2/H2/CO2 (55:35:10), and in absence of H2: N2/CO2 (75:25). Growth in each condition was performed in triplicate. Trimethylamine concentration was measured as described by Krätzer et al.30 OD, Optical Density.