Vibrio amylolyticus sp. nov. and Vibrio gelatinilyticus sp. nov., two marine bacteria isolated from surface seawater of Qingdao

Abstract

Two Gram-stain-negative, oxidase-positive, facultative anaerobic and rod-shaped motile bacteria, designated strains ZSDZ34 and ZSDE26, were isolated from offshore surface seawater collected near Qingdao. Phylogenetic analysis based on 16S rRNA gene sequences placed ZSDE26^T and ZSDZ34^T within the genus Vibrio, family Vibrionaceae, class Gammaproteobacteria. Strain ZSDE26^T was most closely related to Vibrio gallaecicus VB 8.9^T with 97.3 % sequence similarity, whereas ZSDZ34^T was most closely related to Vibrio aestuarianus subsp. cardii DSM 109723^T with 97.8 % sequence similarity. Strain ZSDE26^T grew with 1-5 % (w/v) NaCl (optimum, 4 %), at 16-28 °C (optimum, 28 °C) and at pH 6.0-9.0 (optimum, pH 7.0). Growth of strain ZSDZ34^T occurred with 1-6 % (w/v) NaCl (optimum, 3 %), at 16-37 °C (optimum, 28 °C) and at pH 6.0-9.0 (optimum, pH 7.0). Both strains shared the same major fatty acid components (more than 10 % of total fatty acids) of summed feature 3 (C_{16 : 1} ω7c and/or C_{16 : 1} ω6c), summed feature 8 (C_{18 : 1} ω7c and/or C_{18 : 1} ω6c) and C_{16 : 0}. Additionally, strain ZSDZ34^T contained a higher proportion of iso-C_{16 : 0}. The DNA G+C contents of strains ZSDE26^T and ZSDZ34^T were 42.8 and 44.5 mol%, respectively. On the basis of the results of polyphasic analysis, ZSDE26^T and ZSDZ34^T are considered to represent novel species within the genus Vibrio, for which the names Vibrio amylolyticus sp. nov. (type strain, ZSDE26^T=KCTC 82890^T=MCCC 1K06290^T) and Vibrio gelatinilyticus sp. nov. (type strain, ZSDZ34^T=KCTC 82888^T=MCCC 1K06292^T) are proposed, respectively.

Keywords: Qingdao offshore; Vibrio amylolyticus sp. nov.; Vibrio gelatinilyticus sp. nov.; surface seawater.