ABSTRACT
In industrial fermentation processes, carbon source is one of the crucial factors for reducing cost of production. Methylotrophs have specific metabolic pathways for oxidation and assimilation of C1 compounds. Oxidation of C1 compounds serves for regenerating high energy compounds such as NADH and ATP. Particularly, C1 compounds are very promising feedstocks in fermentation industry. C1-unit relates to the formation and decomposition of several amino acids such as L-methionine, L-serine, glycine, L-tryptophan, L-histidine, nucleic acids, choline, betaine, or lignine. Methylotrophs are attractive as 1-serine producers because their STHM has been known to be highly induced in response to methanol assimilation. Morinaga et al. reported that serine-type methylotrophs actively formed 1-methionine from dl-homocysteine in the presence of methanol as a methyl donor. Coenzyme Q (CoQ) is also an attractive product of methylotrophs. Methylotrophs containing CoQ10 were classified in two groups: pink-pigmented facultative methanol-utilizers and Microcyclus.
