Methylobacterium extorquens (strain ATCC 14718 / DSM 1338 / AM1) is a pink-pigmented facultative methylotrophs Gram-negative bacterium isolated in 1960 in Oxford, as an airborne contaminant growing on methylamine. It was used as a workhorse to characterize the serine cycle for assimilation of the C1-unit of methylene tetrahydrofolate, a central intermediate in methylotrophic metabolism, and more recently the ethylmalonyl-CoA pathway for glyoxylate regeneration. The common trait of all Methylobacterium species is the ability to grow on one or several reduced one carbon (C1) compounds other than methane, most prominently methanol. M. extorquens contains large sets of insertion elements, many of them strain-specific, suggesting an important potential for genomic plasticity. Most of the genomic determinants associated with methylotrophy are nearly identical in all strains with exceptions that illustrate the metabolic and genomic versatility of Methylobacterium species. M.extorquens (strain ATCC 14718 / DSM 1338 / AM1) possesses a unique methylamine utilization (mau) gene cluster, indicating that strain DSM 5838 / DM4 employs an alternative system for growth with methylamine. The mau clusters represent a chromosomal genomic island and is flanked by mobile elements.(Adapted from PMID: 19440302).