Porphyrobacter colymbi sp. nov. isolated from swimming pool water in Tokyo, Japan.

The genus Porphyrobacter was proposed by Fuerst et al. (1993) and, at the time of this writing, comprises six recognized species: P. neustonensis (Fuerst et al., 1993), P. tepidarius (Hanada et al., 1997), P. sanguineus (Hiraishi et al., 2002), P. cryptus (Rainey et al., 2003), P. donghaensis (Yoon et al., 2004) and P. dokdonensis (Yoon et al., 2006). Colonies of Porphyrobacter species are red or orange in color and synthesize bacteriochlorophyll a (Fuerst et al., 1993; Hanada et al., 1997; Hiraishi et al., 2002; Rainey et al., 2003; Yoon et al., 2004, 2006). These strains have been isolated from various environments of fresh water (Fuerst et al., 1993), hot spring water (Hanada et al., 1997; Rainey et al., 2003) and sea water (Hiraishi et al., 2002; Yoon et al., 2004, 2006). In this study, we describe the morphological, physiological and genetic characteristics of the new isolate TPW-24T isolated from swimming pool water and propose that this strain represents a new species in the genus Porphyrobacter, Porphyrobacter colymbi. Strain TPW-24T was isolated from swimming pool water (free residual chlorine: 0.4 mg/L) from Metropolitan Tokyo, Japan in August of 2009 using a plating method with standard agar medium (Nissui Pharmaceutical Co., Ltd., Tokyo, Japan) at 37°C for 24 h. The isolated strain was preserved in the Microbank (Iwaki & Co., Ltd., Tokyo, Japan) and stored at -80°C. The almost complete sequence of the 16S rRNA gene was determined using the MicroSeq 16S rRNA gene bacterial identification kit (Applied Biosystems). A multiple sequence alignment analysis was performed using the CLUSTAL W software program (Thompson et al., 1994) and gaps and unidentified base positions were deleted using the BioEdit (Hall, 1999) software package. Evolutionary distances were calculated using Kimura’s two-parameter model (Kimura, 1980) without alignment gaps and unidentified base positions were taken into account during distance calculations. The phylogenetic tree was constructed using the neighbor-joining method (Saitou and Nei, 1987) and the bootstrap values were calculated on the basis of 1,000 replications (Felsenstein, 1985). The quantitative microplate DNA-DNA hybridization test on the TPW-24T strain and P. donghaensis KCTC 12229T was performed at the TechnoSuruga Laboratory in Shizuoka Prefecture, Japan, as previously described (Ezaki et al., 1989). The methods used to isolate and purify DNA have been previously described (Hamamoto and Nakase, 1995). The levels of DNA reJ. Gen. Appl. Microbiol., 59, 245‒250 (2013)