Preliminary Study On Prokayotic Microorganism Of Salt Lake In Daying, A Hypersaline Environment In Sichuan

Daying salt lake is located in Sichuan Basin of China.Its hypersaline water rich in sodium and chloride origins,and it was draw-out from the 3042m deep underground.It is one of the most saline brine on earth(salinity≈22%,w/v).Since there were no previous reports on the microbiota of this very special hypersaline ecosystem,we undertook this study to evaluate the bacterial diversity of Daying salt lake.Soil sample and water sample of the Daying salt lake were sent to a commercial water chemistry laboratory for ionic composition analysis.The result showed that sodium and chloride are the main ionic constituents of this lake,and the pH=6.0.Liquid enrichment and dilution plating were used to isolate halophilic and halotolerant bacteria from DSL soils and waters.Three mediums(SP,Ma,CM) were used for isolating,finally,185 isolates were yielded.The result showed that the SP medium was the best one,105 isolates were cultivated from it(56.7%).Most of the isolates were yellow and creamy.Different salt concentration media screened 116 halotolerant bacteria,48 moderately halophilic bacteria and 11 extremely halophilic archaea from a total of 185 strains.PH grads experiment indicated that S63-1 grow optimum pH was 9.0.By different cultivated temperature,the optimum temperature of 185 isolates was 37-40℃,one isolate can grow well under 60℃.The 16Sr DNA PCR products of 114 strains were analyzed by ARDRA,and the results showed that a total of 12 different patterns for bacteria presented.Phylogenetic analysis revealed that 114 strains belong to ten genera:Salimicrobiu,Halomonas,Halobacillus,Virgibacillus,Idiomarina,Chromohalobacter,Halovibrio,Alkalibacillus,Halalkalibacillus,Marinococcus.In addition,from the phylogenetic analysis 2 strains may be new genus of Salimicrobium and Halomonas.Phenol-degrading experiment result showed that strain S24-1 degraded 100ml 500mg/L phenol completely during 60-72h.Two mediums(MA,MC) were used for extremely halophilic archaea isolating,finally,111 isolates were yielded.The result showed that the MC medium was the best one,66 isolates were cultivated from it(59.5%).Most of the isolates were red and transparent.By different salt concentration media,57 isolates were extremely halophilic archaea.Phylogenetic analysis revealed that 15 strains belong to extremely halophilic archaea,they were distributed in there genera:Halobacterium,Haloferax,Halorubrum.