Study On The Biotransformation Of Monomer Ginsenoside In The Ginseng Stem And Leaf By Fermentation Of Aspergillus Niger

Ginsenoside is the main active ingredients of ginseng,and the pharmacological activity of rare ginsenoside Rh2,CK and other secondary saponin was significantly higher than that of the major saponins,especially in anti-tumor activity,but the content of these rare ginsenoside in Panax ginseng is too low to satisfy the need of application requirements.The main purpose of this study was to established fermentation system of Aspergillus niger fermented ginseng stems and leaves,the ginsenosides in ginseng stems and leaves was structure modified to increase the monomeric saponin in the fermentation productThe results of this study are as follows:1.The Aspergillus niger(10),which the biomass and extracellular ?-glucosidase activity was the optimum among 21 strains,and having the ability of reduce ginseng stems and leaves lignin,cellulose and hemicellulose,was selected as the liquid fermentation strain of ginseng stems and leaves.2.According to the results of single-factor experiments,when the fermentation time was 3 days,50 m L liquid volume,30.5°C of fermentation temperature and 6.05 initial p H,the content of ginsenoside Rh4 and CK achieved highest.3.According to the results of single-factor experiments,when the fermentation time was 3 days,Optimizationthree of Box-Behnken response surface for fermentation process of ginseng stems and leaves by liquid fermentation of Aspergillus niger Panax by selecting three facors: liquid volume,fermentation temperature and initial p H of fermentation.The optimum fermentation conditions were: when the fermentation time was 3 days,50 m L liquid volume,30.5°C of fermentation temperature and 6.05 initial p H.4.Under the optimum fermentation conditions,the total ginsenoside content of the fermented product was 5.6%,which was 1.32% lower than that of the control group which total saponin content was 6.92% in the stem and leaf.The content of ginsenoside was analysised by HPLC,There were 16 known single saponins in the fermentation products,and 1 species was unknown.Among them,ginsenoside F1,Rk3,Rh4,CK,Rh2 and protopanaxadiol types aglucone PPD and protopanaxatriol types aglucone PPT had not been detected in the control group of ginseng stems and leaves.The content of Rh4 in fermentation products was0.24%,and CK was 0.22%.5.Through single-factor experiments,it was found that the maximum content of ginsenoside F1 in fermentation products reached 1.05% when the liquid volume was 45 m L,the fermentation temperature was 30?,p H 6.0 for 7 days,and the content of ginsenoside F1 in the fermentation products had not been detected in the control group;when the liquid was fermented for 10 days under the conditions of 45 m L liquid volume,30°C fermentation temperature,p H 4.5.The maximum content of ginsenoside Rc in the fermentation product reached 2.76%,which was higher than that of the control group which content was 2.22% in the stem and leaf,that had increased by 5.11 times.At present,many studies have reported on the use of ginseng or ginsenoside extract as a substrate for fermentation.However,no studies have reported on the using ginseng stems and leaves as a substrate for fermentating rare saponin by Aspergillus niger in vitro.The fermentation system of the fermentation of ginseng stems and leaves by Aspergillus niger was established.Using microbes to carry out secondary development of ginseng stems and leaves,improves the utilization of ginseng resources and lay the foundation of directional production of ginsenosides.