Pseudoxanthomonas jiangsuensis sp. nov., a DDT-degrading bacterium isolated from a long-term DDT-polluted soil

A Gram-negative, strictly aerobic, rod-shaped bacterium, designated strain wax(T), was isolated from DDT-contaminated soil in Yangzhou, China. Growth of strain wax(T) was observed at 10-45°C (optimum 30°C) and pH 5.0-10.0 (optimum pH 7.0-8.0). The predominant fatty acids were iso C(15:0) (32.21%) and anteiso C(15:0) (22.2%). The strain contained large amounts of the polar lipids diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylglycerol, but small amounts of an unknown amino-group-containing polar lipid and phospholipids were also present. The major quinone was ubiquinone-8 (Q-8) and the G + C content of the genomic DNA was 67.12 ± 0.8 mol.%. The phylogenetic tree shows that strain wax(T) clustered within the genus Pseudoxanthomonas. Isolate wax(T) showed moderate 16S rRNA gene sequence similarities to Pseudoxanthomonas broegbernensis B1616/1(T) (98.3%), P. suwonensis 4M1(T) (98.2%), P. daejeonensis TR6-08(T) (98%), P. koreensis TR7-09(T) (97.7%), P. kaohsiungensis J36(T) (97.5%), P. mexicana AMX 26B(T) (97.2%), and P. japonensis 12-3(T) (97%). The level of DNA-DNA relatedness between strain wax(T) and Pseudoxanthomonas type strains were low, e.g., P. koreensis TR7-09(T) (25.9%), P. broegbernensis B1616/1(T) (36.4%), P. suwonensis 4M1(T) (27.7%), P. daejeonensis TR6-08(T) (40%), P. kaohsiungensis J36(T) (20.4%), P. mexicana AMX 26B(T) (29.0%), P. japonensis 12-3(T) (33.3%). On the basis of the phenotypic, chemotaxonomic data and molecular properties, strain wax(T) represents a novel species within the genus Pseudoxanthomonas, for which the name Pseudoxanthomonas jiangsuensis sp. nov. is proposed. The type strain is wax(T) (=DSM 22398(T) = CGMCC 1.10137(T)).