Chthonobacter albigriseus gen. nov., sp nov., isolated from grass-field soil

A novel aerobic, Gram-stain-negative and non-motile bacterial strain, designated ED7(T), was isolated from grass-field soil in Cheonan, Korea. Strain ED7(T) utilized methanol and methylamine, but not formate, as carbon and energy sources. The strain was able to grow at 20-42 degrees C (optimum 30-35 degrees C), at pH 7.0-8.5 (optimum pH 7.5-8.0), and in the absence of NaCl. According to the similarities of the 16S rRNA gene sequences, strain ED7(T) was most closely related to the genera Labrenzia (<= 93.3% 16S rRNA gene sequence similarity), Pleomorphomonas (<= 93.1 %) and Prosthecomicrobium (<= 93.1 %). A phylogenetic analysis based on the 16S rRNA gene sequence of strain ED7(T) revealed that it was affiliated with the family Methylocystaceae, being most closely related to the genus Pleomorphomonas. In contrast to Pleomorphomonas koreensis and Pleomorphomonas oryzae, strain ED7(T) did not contain the nifH gene. The DNA G+C content of the genomic DNA of strain ED7(T) was 71.8 mol%. The predominant fatty acids of strain ED7(T) were summed feature 8 (C-18:1 omega 7c and/or C-18:1 omega 6c), summed feature 2 (C-14:0 3-OH, and/or C-16:1 iso I), 11-methyl C-18:1 omega 7c and C-16:0 3-OH. The major isoprenoid quinone was ubiquinone 10 (Q-10). The major polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and an unknown aminophospholipid. Based on phenotypic, chemotaxonomic and genotypic characteristic data, strain ED7(T) could be differentiated from other genera, suggesting that strain ED7(T) represents a novel species of a new genus in the family Methylocystaceae, for which the name Chthonobacter albigriseus gen. nov., sp. nov. is proposed. The type strain of the type species is ED7(T) (=JCM 30603(T) = KCTC 42450(T)).