The Exploitation Of Halophilic Microorganism Resources In Xiaochaidan Salt Lake Of Qinghai And The Optimization Of Ectoine Fermentation Conditions

Objective To excavate microbial resources of Xiaochaidan salt lake and the yield of Ectoine was improved by the accumulation of fermentation conditions.Methods To understand the microbial community structure and diversity of Xiaochaidan salt lake,we carried out the 16 S r RNA gene(V3-V5 region)high-throughput sequencing of bacteria and archaea based on an Illumina sequencing platform.Isolating the microorganism resources of Xiaochaidan salt lake,salt tolerance gradient test of microorganisms.To obtain the optimal combination of the X26 strain with high accumulation of Ectoine by orthogonal experiment and single factor fermentation condition.Results Microorganisms were belonging to definite taxonomic bacteria of 21 phylum43 clas-ses 201 genera and archaea classified to 4 phylum 4 classes 39 genera via high-throu-ghput sequencing.The dominant bacterial genera were belonged to the Bacillus(21.53%),followed by the Chloroplast-norank(6.65%),Marinobacter(4.05%),Oceanobacillus(3.82%),Lactococcus(3.65%)and Pseudomona s(3.46%).The dominant archaeal genera belonged to the unclassified genus(80.84%)within the Woesearchaeota phylum,the genus Halorubrum(6.93%),Methanolobus(3.78%)and Halohasta(3.14%).Through the screening and separation,39 strains halophilic bacteria were obtained from Xiao chaidan salt lake,the dominant bacterial was moderate halophilic.The single factor optimum fermentation conditions of high accumulation Ectoine of Halomonas sp.X26 was temperature: 35?,p H: 8,Na Cl:1.5mol/L,Mg SO4: 0.1mol/L,KCl: 0.25 mol/L,L-glutamate: 0.03mol/L,gassein enzymatic hydrolysater: 12.5g/L.Orthogonal experiment was designed with the best single factor condition.the optimal combination of high accumulation Ectoine was Na+: 1.0 mol/L,Mg2+: 0.1 mol/L,K+: 0.75 mol/L,L-glutamate: 0.035 mol/L,gassein enzymatic hydrolysater:7.5 g/L,the yield of Ectoine was 491.19 mg/L,cell dry weight was 0.70 g/L.Conclusion Xiaochaidan salt lake microbial population structure is complex and abundant,the germplasm resources of microbial is rich,the accumulation of Ectoine is high.Halomonas sp.X26 with high accumulation of Ectoine is acquired,and the preliminary study on optimization of the combination of fermentation factors could provide theoretical basis for the following application and development.