Paracoccus simplex sp. nov., a New Methylamine-Utilizing Facultative Methylotroph

— A facultative methylotroph, strain F5 Т , which uses methylamine and a broad spectrum of polycarbon substrates as carbon and energy sources, was isolated from silt of a freshwater lake in the southern Moscow region. The cells were gram-negative, coccoid, non-spore-forming, nonmotile, colorless, reproducing by binary fission and possessing a capsule. The organism was mesophilic, neutrophilic, not halophilic, oxidase- and catalase-positive, and capable of nitrate reduction to nitrite. Methylamine was oxidized by amine dehydrogenase and via the icl - serine pathway of С 1 metabolism, as was indicated by activities of hydroxypyruvate reductase and serine-glyoxylate aminotransferase and by the absence of hexulosephosphate synthase and ribulose bisphosphate carboxylase. Predominant fatty acids were C 18:1ω7c (72.3%) and C 16:0 (11.6%). Phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylethanolamine were the dominant phospholipids. The G + C DNA content was 65.8 mol % ( T m ). Q 10 was the dominant ubiquinone. Strain F5 T exhibited high similarity of the 16S rRNA gene sequences with Paracoccus strains: P. aminovorans JCM7685 T = VKM B-2140 Т (98.0%), P. huijuniae FLN-7 Т (97.9%), and P. limosus NB88 T (97.5%). However, the level of DNA-DNA relatedness between the strains F5 Т and P. aminovorans Т was only 21 ± 3%. Based on the data obtained, strain F5 Т was identified as a new Paracoccus species with proposed name Paracoccus simplex sp. nov. (= VKM B-3226 T = CCUG 71989 T ).