Study On Biodiversity And Enzyme-Producing Characteristic Of Halophilic Bacteria From Lop Nur Region In Xinjiang

The research was the first time to collect the soil samples and isolate the halophilic bacteria from the Lop Nur in Xinjiang.To understand the diversity of halophilic bacter -ia and the extracellular hydrolytic enzymes diversity in the Lop Nur.One hundred and eight halophilic bacteria stains were isolated from the salt crust and saline soils from"big ear-shaped"part of Lop Nur region in Xinjiang. The results indicated that the media which added the educt of the salt crust was proved to be more effective on the enrichment culture and isolation of the halophile.The growth pH range were range from 6.0 to 10.0, and the optimum pH were 7.0～8.0 of the halophile. According to growth NaCl concentration, the bacteria were classified as moderate halophile, extreme halophile and halotolerant, the proporation were 24%, 27%, 49%, respectively. Most of the halophilic bacteria have extensivead aptability to different Na+, K+, Mg2+. For few of the halophile and halotolerant strains, their growth only depended on one of the positive ions respectively, such as Na+, K+, Mg2+ and Ca2+.By analysis of the restriction patterns of amplified 16S rDNA (ARDRA), and use a genomic fingerprinting technique,ERIC-PCR.Then representatives of each operational taxonomic units(OTU) were randomly chosen for the determination of 16S rDNA sequence. The phylogenetic analysis revealed that all of the isolates were clustered into 10 groups and other two unknown groups. Four isolates may represent two new genera and two new species.The Shannon index is 2.827 and the Margalef index is 2.349 .These results suggest that diverse halophilic bacteria exist in and the unknown halophilic bacteria thrive in Lop Nur.Industrially important enzymes from these strains were screened subsequently. The result showed that 30 strains produce protease, 25 strains produce amylase, 14 strains produce lipase and 4 strains produce cellulose.Enzyme characteristics of protease and amylase from halophilic bacteria were investigated in this study.The result show the protease and amylase Belong to Alkaline protease and Neutral amylase.The protease and amylase appears higher activity.It not only appears the good Thermal stability and pH stability,but also stable in concentrated solution of NaCl.By means of orthogonal experiment, the optimum fermenting condition of produ -cting amylase is intitial pH value,8.0; concentration of NaCl,10%; yeast extract,4%; cornmeal,1%.And the optimum fermenting condition of producting protease is intitial pH value 9.0; concentration of NaCl,10%; yeast extract,4%;cornmeal,4%.