Marinobacter persicus sp. nov., a moderately halophilic bacterium from a saline lake in Iran

Abstract

A Gram-negative, non-endospore-forming, rod shaped, strictly aerobic, moderately halophilic bacterium, designated strain M9B(T), was isolated from the hypersaline lake Aran-Bidgol in Iran. Cells of strain M9B(T) were found to be motile and produce colonies with an orange-yellow pigment. Growth was determined to occur between 5 and 20 % (w/v) NaCl and the isolate grew optimally at 7.5-10 % (v/w) NaCl. The optimum pH and temperature for growth of the strain were determined to be pH 7.0 and 35 °C, respectively, while it was able to grow over pH and temperature ranges of 6-8 and 25-45 °C, respectively. Phylogenetic analysis based on the comparison of 16S rRNA gene sequences revealed that strain M9B(T) is a member of the genus Marinobacter. The closest relative to this strain was found to be Marinobacter hydrocarbonoclasticus MBIC 1303(T) with a similarity level of 97.7 %. DNA-DNA hybridization between the novel isolate and this phylogenetically related species was 13 ± 2 %. The major cellular fatty acids of the isolate were identified as C16:0, C19:1 ω6c, C18:1 ω9c and C16:1 ω9c. The polar lipid pattern of strain M9B(T) was determined to consist of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylserine and three phospholipids. Ubiquinone 9 (Q-9) was the only lipoquinone detected. The G+C content of the genomic DNA of this strain was determined to be 58.6 mol%. Phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness data suggest that this strain represents a novel species of the genus Marinobacter, for which the name Marinobacter persicus sp. nov. is proposed. The type strain of Marinobacter persicus is strain M9B(T) (=IBRC-M 10445(T) = CCM 7970(T) = CECT 7991(T) = KCTC 23561(T)).