Identification And Polyphasic Taxomony Study Of A Moderately Halophilic Bacterium Strain Pontibacillus Yanchengensis Sp. Nov

Living in high salt environments, halophilic microorganisms possess unique genes, cell structures and functions, and become one of the most important and highly promising microbial resources. They are hotpoints of current researches due to the potencial application in many aspects, such as food, medicine, cosmetic, agriculture and environmental protection.Our Country is vast and possesses a long coastline. There are hundreds of salt fields in the southeast coastal areas and many kinds of salt lakes and salt mines in interior areas. However, researches of the isolation and identification of halophilic microorganisms in China are still limited.In this study, we collected saline soil samples from salt field in Yancheng, Jiangsu province and isolated a halophilic bacterium strain Y32.Using polyphasic taxomony study, it was found that strain Y32 was a Gram-positive, aerobic, moderately halophilic bacterium. The optimum range of NaCl concentration is 6-8%(w/v),optimum pH range is 7.0-8.0, and optimum temperature range is 35-40℃. The bacterium was oxidase-and catalase-positive. It can reduce nitrate to nitrite, hydrolyze aesculin and starch, but not casein, L-tyrosine, Tween 80, gelatin or urea. It was negative for production of H2S or indole, oxidation/fermentation of glucose, in Methyl Red and Voges-Proskauer tests. Major cellular fatty acid were anteiso-C15:0,iso-C15:0,iso-C16:0,iso-C14:0,anteiso-C17: 0 and C16:1ω7c alcohol. The predominant menaquinone was menaquinone-7 (MK-7).The cell wall peptidoglycan type was meso-diaminopimelic acid. DNA G+C content was 40.3 mol%.Strain Y32 exhibited similarities of 16S rRNA to the type strains of Pontibacillus species between 96.0%-97.8%. DNA-DNA relatedness between strain Y32 and Pontibacillus marinus BH030004T which possessed the highest similarity with Y32 was 41.8%. The phylogenetic trees based on 16S rRNA gene sequence revealed that strain Y32 fell within the branch of the genus Pontibacillus. On the basis of phenotypic, chemotaxonomic and phylogenetic evidences, strain Y32T is affiliated to Pontibacillus, but is clearly differentiated from other species of this genus and represents a novel member, for which the name Pontibacillus yanchengensis sp.nov. is proposed. The type strain is Y32T(=CCTCC AB209311T=NRRL B-59408T) which stored in China Center for Type Culture Collection (CCTCC) and Northern Regional Research Laboratory (NRRL)。...