TheSporomusagenus comprises anaerobic spore-forming acetogenic bacteria that stain Gram-negative.Sporomusaspecies typically grow with one-carbon substrates and N-methylated compounds. In the degradation of these compounds methyltransferases are involved. In addition,Sporomusaspecies can grow autotrophically with H2 and CO2, and use a variety of sugars for acetogenic growth. Here we describe a genome analysis ofSporomusastrain An4 and a proteome analysis of cells grown under five different conditions. Comparison of the genomes ofSporomusastrain An4 andSporomusa ovatastrain H1 indicated that An4 is aS. ovatastrain. Proteome analysis showed a high abundance of several methyltransferases, predominantly trimethylamine methyltransferases, during growth with betaine, whereas trimethylamine is one of the main end-products of betaine degradation. In methanol degradation methyltransferases are also involved. In methanol-utilizing methanogens, two methyltransferases catalyse methanol conversion, methyltransferase 1 composed of subunits MtaB and MtaC and methyltransferase 2, also called MtaA. The two methyltransferase 1 subunits MtaB and MtaC were highly abundant when strain An4 was grown with methanol. However, instead of MtaA a methyltetrahydrofolate methyltransferase was synthesized. We propose a novel methanol degradation pathway inSporomusastrain An4 that uses a methyltetrahydrofolate methyltransferase instead of MtaA.