Studies On Taxonomy Of The Halophiles From Hexi In Gansu

Microorganisms were isolated from samples collected from Hexi in Gansu province.Study on systematic taxonomy of isolated halophiles had been done using polyphasic technology including morphological and cultural characteristic observations,physiological and chemical tests,analysis of 16S rRNA sequences.Twenty eight halophiles were isolated from samples with solid medium,deep researches of four strains had been done.Three strains belong to the genus of Marinococcus,they are DH1,DH3 and AF2.They are all Gram-positive,spherical,aerobic,non-spore-forming,and mobile.The optimum growth temperature and consentration of NaCI are 28℃and 8%,respectively. Catalase-positive but negative for oxidase,urase,esterase.And negative for casein and starch hydrolysis,gelatin liquefaction.No growth of AF2 occur without NaCl,but can DH1 and DH3;the nitrate reduction of AF2 is positive,but DH1 and DH3 are negative;DH1 vigor impact is significantly in the absence of Mg²⁺,DH3 is not so significantly,AF2 is not sensitive to Mg²⁺; There are significant differences of the three strains in carbon-source utilization and susceptibility to antibiotics.AK5 belong to the genus of Lentibacillus,cells are gram-positive,rod-shaped, 0.5-0.7×1.5-3.0um,mobile,non-spore-forming,aerobic.The optimum temperature is 37℃. Concentration ranges of NaCl for growth are 0%-15%.Positive for catalase and urase,but oxidase -negative.And positive for starch hydrolysis,gelatin liquefaction,nitrate reduction,in methyl red and Voges-Proskauer,but negative for casein and cellulose hydrolysis,H₂S and indole production, acid production from fructose.Morphological characteristics,physiological and biochemical characteristics were investigated,phylogenetic analysis were completed by comparation of these strains with corresponding standard strains.Our data suggest that four potential novel species of the genus of Marinococcus and Lentibacillus were proposed.