Modicisalibacter tunisiensis gen. nov., sp. nov., an aerobic, moderately halophilic bacterium isolated from an oilfield-water injection sample, and emended description of the family Halomonadaceae Franzmann et al. 1989 emend Dobson and Franzmann 1996 emend. Ntougias et al. 2007

Abstract

An aerobic, moderately halophilic, Gram-negative, motile, non-sporulating bacterium, strain LIT2T, was isolated from an oilfield-water injection after enrichment on crude oil. Strain LIT2T grew between 15 and 45 °C and optimally at 37 °C. It grew in the presence of 1–25 % (w/v) NaCl, with an optimum at 10 % (w/v) NaCl. Predominant fatty acids were C16 : 0 (26.9 %), C18 : 1 ω7c (22.6 %), C16 : 1 ω7c (20.4 %) C19 : 0 cyclo ω8c (10.9 %) and C17 : 0 (8 %). Interestingly, the relative percentages of these last two fatty acids were intermediate compared with most species among the family Halomonadaceae for which fatty acid composition has been determined. The DNA G+C content was 53.7 mol%, which is very low among the family Halomonadaceae. Strain LIT2T exhibited 16S rRNA gene sequence similarity values of 94.06–95.15 % to members of the genus Chromohalobacter, 94.21–94.65 % to members of the genus Halomonas and 93.57 % with the single species representative of the genus Cobetia. Based on the phylogenetic and phenotypic evidence presented in this paper, we propose the name Modicisalibacter tunisiensis gen. nov., sp. nov. to accommodate strain LIT2T. The type strain of Modicisalibacter tunisiensis is LIT2T (=CCUG 52917T =CIP 109206T). A reassignment of the descriptive 16S rRNA signature characteristics of the family Halomonadaceae permitted placement of the new genus Modicisalibacter into the family.