Acinetobacter mesopotamicus sp. nov., Petroleum-degrading Bacterium, Isolated from Petroleum-Contaminated Soil in Diyarbakir, in the Southeast of Turkey.

A new petroleum-degrading bacterium, designated strain GC2, was isolated from Bozkuş 1 petroleum station in Diyarbakir, located in the southeast of Turkey. Cells were Gram-negative staining, aerobic, coccoid-rods, non-motile, non-spore-forming. The bacterium was found to degrade 100% of n-alkanes ranging from C11 to C34 presented in the 1% crude oil after incubation of 7 days. The membrane phospholipids were 1,2 diacylglycero-3-phosphorylethanolamine (PEA), phosphatidylglycerol (PG), dipalmitoyl-sn-glycerol 1- phosphocholine (PC1), 1,2 dipalmitoyl-sn-glycero-3-phosphocholine monohydrate (PC3), cardiolipin also called diphosphatidylglycerol (CL) and l-α- phosphatidic acid, dipalmitoyl (AP); predominant respiratory ubiquinone was Q-8 and C16:0, C18:1ω9c and C16:1 were the major cellular fatty acids. The 16S rRNA sequence analysis revealed that the strain GC2 was a member of genus Acinetobacter and was most closely related to Acinetobacter lwoffii DSM 2403 (99.79%), Acinetobacter pseudolwoffii ANC 5318 (98.83%) and Acinetobacter harbinensis HITLi 7 (98.14%). The rpoB and gyrB gene sequence analysis confirmed that the strain GC2 was a member of genus Acinetobacter and that the closest relative was Acinetobacter lwoffii DSM 2403 (99.08% and 100% similarity, respectively). DNA-DNA hybridization values between GC2 and its closest relatives ranged from 65.6% (with A. lwoffii) to 5.1% (with A. venetianus). The whole genome sequence of strain GC2 was obtained. The DNA G + C content of this strain was determined to be 42.9 mol %. ANI indexes, in silico estimations of DDH values and wet lab DDH values demonstrated that strain GC2 represents an independent genomospecies. On the basis of phenotypic characteristics, chemotaxonomic, phylogenetic data and DNA-DNA hybridization and whole genome analysis, we propose to assign strain GC2 as a new species of the genus Acinetobacter, for which the name Acinetobacter mesopotamicus sp. nov. is proposed. The type strain of this species is GC2 (DSM 26953 T = JCM 31073 T). The whole genome of strain GC2 has been deposited at DDBJ/ENA/GenBank under the accession JAALFF010000000.