Screening Of Ginsenoside Transforming Strain And Analysis Of Its Products

Objective: To select microorganisms that can transform rare ginsenosides from soil,and further research the metabolic mechanism and characteristics of the strain.Methods: The enrichment and culture of microorganisms were carried out with the total saponins of ginseng stems and leaves as substrate.After separation,a single microorganism was obtained,and then ginsenoside Re,Rg1 and Rb1 were used as substrates for transformation.The transformed ginsenosides were detected by UHPLC-quadrupole-orbit trap MS.The transformation process of ginsenoside Rb1 from the strain NO.28 was optimized by single factor analysis.The characteristics of the strain NO.28 were identified by wholegenome sequencing using the ONT sequencing platform and the Nanopore sequencing platform,and the functional annotation of GO,COG and CAZy were analyzed.Results: Thirty kinds of microbes were screened out which have the ability to transform.There were four kinds of microorganisms which could obviously transform ginsenoside Rb1,two kinds of microorganisms which could obviously transform ginsenoside Rb1 and Rg1,one kind of microorganism which could obviously transform ginsenoside Rb1 and Re,and four kinds of microorganisms could obviously transform ginsenoside Rb1,Re and Rg1.The optimum conditions for transformation of ginsenoside Rb1 by strain NO.28 were determined as follows: transformation time 24 h,transformation p H7.0,transformation temperature 27℃,and the conversion rate was 48.40%.The whole genome sequencing was performed for strain NO.28,whose genome length was 4215536 bp and the GC content was 43.51%.Genome prediction encoded 4229 open reading frames(ORFs).The functions of GO analysis were divided into 43 categories,and COG analysis were divided into 25 categories.CAZy analysis showed that there were 108 genes related to the transformation of ginsenosides.Conclusion: The soil of ginseng field was rich in a large number of microorganisms.The screening method of transforming rare ginsenoside microorganisms was further clarified,which laid a foundation for future related research.The whole genome sequencing results of strain NO.28 provided the basis for further study on the transformation of ginsenosides by this strain.