Numerical taxonomic and chemical studies on obligate methanol utilizing bacteria.

One hundred and fifteen cultures, including obligate and facultative methylotrophs and members of possibly related taxa, were studied. All cultures (representing 102 strains and 13 duplicate cultures) were tested for 135 characters based on their morphology, physiology and biochemistry and the results were subjected to computer analyses. The polar lipid composition of all the cultures was examined by two-dimensional thin layer chromatography. The isoprenoid quinone compositions, and mol % G+C base ratio values were determined for all the obligate methanol utilizing bacteria, and also for some other strains representative of the clusters formed in the numerical taxonomic study. Deoxyribonucleic acid - DNA hybridization values amongst strains of obligate methanol utilizing bacteria were determined using a novel filter method of hybridization developed during the study. The results indicate that the obligate methanol utilizing bacteria all exhibit a high phenotypic similarity and are taxonomically distinct from all the facultative methanol utilizing bacteria studied and from the pseudomonads. The results also indicate that the obligate methylotrophs studied represent two distinct taxa of at least separate generic status, i.e. Methylobacillus and a taxon which can be equated with "Methylophilus". Both of these genera can be further subdivided into species or subspecies.