Methylobacillus: a New Genus of Obligately Methylotrophic Bacteria

Abstract

A new genus and species of obligately methylotrophic bacteria are described. These bacteria are nonmotile, gram-negative rods occurring singly and in pairs. Only methanol and methylamine can support growth. Formaldehyde fixation occurs mainly via the 3-hexulose phosphate pathway, and cell extracts contain a glutathione-independent, nicotinamide adenine dinucleotide-linked formaldehyde dehydrogenase. The deoxyribonucleic acid base composition is 54.1 mol% guanine plus cytosine. Nitrogen-limited cells accumulate over 5% of their dry weight as a glycogen-like reserve material. This polysaccharide is a homoglucan which is similar to glycogen in its iodine-staining properties and its degree of degradation by phosphorylase a. Some of the glucose molecules are α-1,4 linked, and the presence of other types of bonds in the glucan is implied. The name of the genus proposed for these bacteria is Methylobacillus gen. nov. The name of the type species, Methylobacillus glycogenes sp. nov., refers to the ability of this species to form a glycogen-like reserve material. The type strain of M. glycogenes is T-11 (= ATCC 29475).