Marinobacter aquaeolei sp. nov., a halophilic bacterium isolated from a Vietnamese oil-producing well

Abstract

Several strains of moderately halophilic and mesophil ic bacteria were isolated a t the head of an oil-producing well on an offshore platform in southern Vietnam. Cells were Gram-negative, non-spore-forming, rod-shaped and motile by means of a polar f lagellum. Growth occurred a t NaCl concentrations between 0 and 20%; the optimum was 5% NaCl. One strain, which was designated VT8l, could degrade n-hexadecane, pristane and some crude oil components. It grew anaerobically in the presence of nitrate on succinate, citrate or acetate, but not on glucose. Several organic acids and amino acids were utilized as sole carbon and energy sources. The major components of its cellular fatty acids were Clzr0 3-OH, c 1 6 : 1 09c, c16:o and C18:1 w9c. The DNA G+C content was 557 mol0/o. 165 rDNA sequence analysis indicated that strain VT8T was closely related to Marinobacter sp. strain CAB (99.8% similarity) and Marinobacter hydrocarbonoclasticus (99-4 YO si m i la r i t y) . Its antibiotic resistance, isoprenoid quinones and fatty acids were similar to those of Marinobacter hydrocarbonoclasticus and Pseudomonas nautica. However, the whole-cell protein pattern of VT8T differed from that of other halophilic marine isolates, including P. nautica. DNA-DNA hybridization indicated that the level of relatedness to Marinobacter hydrocarbonoclasticus was 65 O/ O and that to P. nautica was 75%. Further differences were apparent in Fouriertransformed IR spectra of cells and lipopolysaccharide composition. It is proposed that VT8T should be the type strain of a new species and should be named Marinobacter aquaeolei. P. nautica may have been misclassified, as suggested previously, and may also belong to the genus Marinobacter.

Anaerobic utilization of toluene by marine alpha- and gammaproteobacteria reducing nitrate

“…Marinobacter species are Gram-negative, halophilic bacteria able to grow heterotrophically on a wide range of substrates with oxygen or nitrate as a terminal electron acceptor (Gauthier et al, 1992;Huu et al, 1999). Although it has previously been demonstrated that Marinobacter species are phylotypes from the n-hexane and toluene enrichment cultures performed with TB, ML and LD sediments, and of the toluenedegrading denitrifiers isolated from NS and BS sediments, with selected reference sequences of the proteobacteria.…”

Marinobacter salinus sp. nov., a moderately halophilic bacterium isolated from a tidal flat environment

“…Several species of the genus Marinobacter (i.e. Marinobacter aquaeolei, Marinobacter maritimus and Marinobacter algicola) have been associated with aromatic and aliphatic hydrocarbon degradation [1,2,[9][10][11]. This may indicate a functional role in the organic carbon cycle, as they constitute one of the dominant bacterial community groups in contaminated environments [12].…”

Marinobacter santoriniensis sp. nov., an arsenate-respiring and arsenite-oxidizing bacterium isolated from hydrothermal sediment

“…A further 19 species with validly published names have subsequently been included within the genus (Antunes et al, 2007; Gorshkova et al, 2003;Green et al, 2006;Gu et al, 2007;Guo et al, 2007; Kim et al, 2006;Liebgott et al, 2006;Martin et al, 2003; Romanenko et al, 2005;Shieh et al, 2003;Shivaji et al, 2005;Xu et al, 2008;Yoon et al, 2003Yoon et al, , 2004Yoon et al, , 2007; Marinobacter aquaeolei (Huu et al, 1999) has been proposed to be a synonym of Marinobacter hydrocarbonoclasticus (Marquez & Ventosa, 2005). These species are motile, halophilic, Gram-negative gammaproteobacteria isolated from saline terrestrial or, more typically, marine environments.…”