Characterization of methanotrophic bacteria on the basis of intact phospholipid profiles

The intact phospholipid profiles (IPPs) of seven species of methanotrophs f rom all three physiological groups, type I, II and X, were determined using liquid chromatography/electrospray ionization/mass spectrometry. In these methanotrophs, two major classes of phospholipids were found, phosphalidylg lycerol (PG) and phospilatidylethanolamine (PE) as well as its derivatives phosphatidylmethylethanolamine (PME) and phosphatidyldimethylethanolamine ( PDME). Specifically, the type I methanotrophs, Methylomonas methanica, Meth ylomonas rubra and Methylomicrobium album BG8 were characterized by PE and PG phospholipids with predominantly C16:1 fatty acids. The type II methanot rophs, Methylosinus trichosporium OB3b and CSC1 were characterized by phosp holipids of PG, PME and PDME with predominantly C18:1 fatty acids. Methyloc occus capsulatus Bath, a representative of type X methanotrophs, contained mostly PE (89% of the total phospholipids). Finally, the IPPs of a recently isolated acidophilic methanotroph, Methylocella palustris, showed it had a preponderance of PME phospholipids with 18:1 fatty acids (94% of total). P rincipal component analysis showed these methanotrophs could be clearly dis tinguished based on phospholipid profiles. Results from this study suggest that IPP can be very useful in bacterial chemotaxonomy. (C) 2000 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.