Vibrio xiamenensis sp. nov., a cellulase-producing bacterium isolated from mangrove soil

Abstract

A taxonomic study was carried out on a cellulase-producing bacterium, strain G21T, isolated from mangrove soil in Xiamen, Fujian province, China. Cells were Gram-negative, slightly curved rods, motile with a single polar flagellum. The strain grew at 15–40 °C and in 0.5–10 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain G21T belonged to the genus Vibrio and formed a clade with Vibrio furnissii ATCC 350116T (97.4 % sequence similarity), V. fluvialis LMG 7894T (97.1 %) and V. ponticus CECT 5869T (96.1 %). However, multilocus sequence analysis (using rpoA, recA, mreB, gapA, gyrB and pyrH sequences) and DNA–DNA hybridization experiments indicated that the strain was distinct from the closest related Vibrio species. Additionally, strain G21T could be differentiated from them phenotypically by the ability to grow in 10 % NaCl but not on TCBS plates, its enzyme activity spectrum, citrate utilization, oxidization of various carbon sources, hydrolysis of several substrates and its cellular fatty acid profile. The G+C content of the genomic DNA was 46.0 mol%. The major cellular fatty acids were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0 and C18 : 1ω7c. The major polar lipids were phosphatidylethanolamine and phosphatidylglycerol, with trace amounts of diphosphatidylglycerol. The predominant quinones were Q-8 and Q-7. Based on phylogenetic, phenotypic and chemotaxonomic characteristics and DNA–DNA hybridization analysis, it is concluded that strain G21T represents a novel species of the genus Vibrio , for which the name Vibrio xiamenensis sp. nov. is proposed. The type strain is G21T ( = DSM 22851T  = CGMCC 1.10228T).