HEAVY METAL-TOLERANT AND PSYCHROTOLERANT BACTERIUM Acinetobacter pakistanensis SP. NOV. ISOLATED FROM A TEXTILE DYEING WASTEWATER TREATMENT POND

A Gram-stain negative, cocci to short rod, non-motile, strictly aerobic, heavy metal-tolerant and psychrotolerant bacterium, designated NCCP-644^T, was isolated from a textile dyeing wastewater treatment pond. The optimum (and ranges of) temperature and pH for growth of strain NCCP-644^T was 20-25°C (3-37°C) and 7–8 (6-10), respectively. The strain can tolerate 0-3% NaCl (w/v) and heavy metals (Cr 2700 ppm, As 3000 ppm, Pb 2100 ppm and Cu 2700 ppm) in tryptic soya agar medium. The sequences of the 16S rRNA gene and three housekeeping genes, gyrB, rpoB and atpD, of strain NCCP-644^T showed the highest similarity (98.3, 91.9, 95.3 and 96.6 %, respectively) with the strain Acinetobacter kyonggiensis KSL5401-037^T. Phylogenetic analyses from the sequence of the16S rRNA, gyrB and rpoB genes also revealed the affiliation of NCCP-644^T with members of the genus Acinetobacter. The chemotaxonomic data [major quinones as Q-9; major cellular fatty acids as summed feature 3 (iso-C15 :0 2OH/C16 :1ω7c) followed by C18:1 ω9c, C16:0, and C12:0 3-OH; major polar lipids as diphosphatidyl glycerol, phosphatidyl serine, phosphatidyl monomethyl ethanol, phosphatidyl inositol, phosphatidyl ethanolamine, phosphatidyl glycerol and one unknown phospholipid] also support the affiliation of strain NCCP-644^T with the genus Acinetobacter. The level of DNA–DNA relatedness between strain NCCP-644^T and the closely related type strains of the genus Acinetobacter was 54.7 %. Based on the phylogenetic analyses, DNA–DNA hybridisation and biochemical characteristics, strain NCCP-644^T differed from the validly named Acinetobacter species and thus, it represents a new species. The name, Acinetobacter pakistanensis sp. nov.is proposed for the type strain NCCP-644^T (= LMG 28467^T = KCTC 42081^T = JCM 18977^T).