Fig. 1: DIET facilitates efficient H2-independent methylotrophic methanogenesis by M. luminyensis.
Pre-reduced modified MM medium was used in all experiments, and all the cultures were initiated with the same inoculation sizes and incubated at 37 °C. A, B M. luminyensis CZDD1 (M.l), C. malenominatum CZB5 (C.m) monocultures, and coculture of the two were all cultured in 375 μmol methanol. The M. luminyensis monoculture was purged with 0.1 MPa H2, and the C. malenominatum monoculture and the co-culture were purged with 0.1 MPa N2. 0.2 MPa of 10% CO and 90% N2 was added to cultures to inhibit [NiFe] hydrogenase activity. Methane (A) and H2 accumulations (B) were monitored. C Aggregations in the 6th subcultures of the coculture. D Using Cy3 (red)- and Cy5 (green)-labeled 16S rRNAs to specifically probe M. luminyensis and C. malenominatum, respectively, FISH was performed on the coculture aggregates (left). Bright field micrograph of the same aggregates (right). Bars indicated 25 μm. E, F Cocultures were initiated with 10% each of M. luminyensis (M.l) and G. metallireducens (G.m, E), or its pilA deletion mutant (ΔpilA, F) into 200 μmol methanol and 100 μmol ethanol. Methane in headspace, and methanol and ethanol in liquid culture were monitored. Data are averages and standard deviations of three replicates.
