Paucibacter oligotrophus sp nov., isolated from fresh water, and emended description of the genus Paucibacter

A Gram-stain-negative, rod-shaped, non-spore forming, motile and strictly oxidative bacterium, strain CHU3(T), was isolated from fresh water in the Daecheong Reservoir, South Korea. A comparison of the 16S rRNA gene sequence showed that the novel bacterium is closely related to Paucibacter toxinivorans 2C20(T) (=KCTC 42569(T)) with a sequence similarity value of 97.8 %, Pelomonas saccharophila DSM 654(T) (=KCTC 52256(T)) with 97.4% similarity and Pelomonas aquatica CCUG 52575(T) (=KCTC 42961 T) with 97.3% similarity, respectively. The major fatty acids (> 10 %) of the isolate were summed feature 3 (C-16:1 omega 7c and/or C-16:1 omega 6c) and C-16:0. Ubiquinone-8 was detected as the respiratory quinone. The polar lipids contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine and an unidentified aminolipid. The DNA G+C content was 62.5 mol%. DNA-DNA hybridization experiments with Paucibacter toxinivorans KCTC 42569(T) (=2C20(T)), Pelomonas saccharophila KCTC 52256(T) (=DSM 654(T)) and Pelomonas aquatica KCTC 42961(T) (=CCUG 52575(T)) resulted in relatedness values of 20% ( reciprocal 11 %), 16% ( reciprocal 17 %) and 15% ( reciprocal 19 %), respectively. The phylogenetic analysis, DNA-DNA hybridization value, polar lipids, fatty acid composition and other physiological characteristics confirmed that strain CHU3(T) represents a novel species in the genus Paucibacter for which the name Paucibacter oligotrophus sp. nov. is proposed. The type strain is CHU3(T) (= KCTC 42519(T)=CICC 24092(T)). An emended description of the genus Paucibacter is also proposed on the basis of new data obtained in this study.