Analysis Of Structure Characteristics Of Endogenous And Soil Microbial In Panax Quinquefolius L.and Biotransformation Ginsenoside

Ginsenosides are the major secondary metabolites in plants of the Panax genus that have been utilized to treat many diseases,which pharmacological activity is related to the sugar chain in its structure,the shorter the sugar chain,the higher the pharmacological activity.Nowadays,most studies have focused on the preparation of ginsenoside with high activity from glycosylated ginsenosides by microbial transformation,but few small studies dealed with finding active strains from Panax quinqueflius.L and its rhizosphere soil,which microbial resources need to be developed and utilized.In this paper,high-throughput sequencing technique andtraditional pure culture technique were used for to analyze the microbial diversity and biotransformation activity of endophytes and rhizosphere soil from Panax quinqueflius.L,aimed to look for strains with ginsenoside transformation activity.It is hoped that the active substance resources in plants of the Panax genus can be utilized to the maximum,and also provides medicinal substance ginsenosides for the pharmaceutical industry to treat various diseases and protect human health.The research results are as follows:1.The results of bacterial flora structure information show that Panax quinqueflius L.endophytic flora were different from that of rhizosphere soil microbial flora,the dominant phyla in Panax quinqueflius L.endophytes and rhizosphere soil microorganisms were Firmicutes(50%)and Actinobacteria(63.6%),respectively,whereas the dominant genera were Lactobacillus(18.6%)and Arthrobacter(22.8%)respectively.The prediction results of bacterial flora function information show that the ginsenoside conversion ability of the Panax quinqueflius L.endophytic flora was better than that of the rhizosphere soil microbial flora,and the ginsenoside synthesis ability of the Panax quinqueflius L.rhizosphere soil microbial flora was better than that of endophytic flora.2.The method of traditional culture and separation was used to obtain the microorganisms from Panax quinqueflius L.and its rhizosphere soil,a strain of G9 y with the ability to convert ginsenoside Rc into Rd was screened from endophytic bacteria isolated from Panax quinqueflius L.The transformed product was confirmed by high performance liquid chromatography(HPLC)analysis.Bacteria G9 y was identified as belonging to the genus Bacillus by molecular biology,morphology,physiological and biochemical analysis,and named Bacillus sp.G9 y.3.The optimal conditions of biotransformation of ginsenoside Rc by strain G9 y were preliminarily investigated.The final result was: after the strain was culture for 4hours,ginsenoside Rc was added,the transformation temperature was 45℃,and the p H was 7.Based on the optimal conditions,ginsenoside Rc could be completely converted into ginsenoside Rd by strain G9 y after 21 hours.4.The results show that ginsenoside glycosidases exists in the intracellular and extracellular of strain G9 y,and the conversion activity of intracellular enzymes was higher than that of extracellular enzymes as determined by thin-layer chromatography(TLC)analysis.The strain G9 y was fermented for 48 hours,stained cells were collected by centrifugation,and then disrupted to obtain the crude intracellular enzyme solution.After the crude enzyme solution was subjected to ammonium sulfate precipitation and ion exchange chromatography,a high-purity enzyme solution was obtained,the molecular weight of enzyme protein was about 45 k Da analyzed by SDS-PAGE.