For the chemotaxonomic classification of microorganisms, polar lipid patterns are often used to distinguish different types of viable microorganisms. In this study, the cellular polar lipid composition of Leucobacter exalbidus was analyzed by Liquid Chromatography ElectroSpray Ionization-Mass Spectrometry (LC-ESI-MS). By LC-ESI-MS analysis, phosphatidylglycerol (PG) and diphosphatidylglycerol (DPG) as well as several unknown compounds were found. Furthermore, the results from LC-ESI-MS showed that two dialkylether polar lipids were present in Leucobacter exalbidus. Dialkylether polar lipids are primarily found in hyperthermophilic bacteria, archaea, and sulfate-reducing bacteria. Based on the data obtained from LC-ESI-MS, it was determined that two ether phospholipids were dialkyl (33:0) phosphatidylglycerol, and dialkyl (32:0) phosphatidylglycerol. In this study, dialkyl ether polar lipids were found in the phylum Actinobacteria for the first time.

Compost contains various thermophilic bacteria; however, few reports describe the isolation of novel thermophilic bacteria from compost. Eighty-three strains were isolated from compost using the media containing the antibiotics such as kanamycin. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the identify of 28 putative bacteria were 88-98% with known bacterial speceies, and formed eight independent lineages in the phyla Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, and Chloroflexi.