Optimization Of Liquid Fermentation Of Nucleosides From Sanghuangporus Vaninii And Their Biological Activities

Sanghuangporus vaninii is a valuable medicinal fungus,which contains nucleoside components that can be developed into pharmaceuticals and health products with antiviral,antitumor and antibacterial activities.Currently,the cultivation of Sanghuang is mainly based on traditional fruiting body culture,but compared to liquid fermentation,fruiting body culture has disadvantages such as high cost,long cycle,and unstable output,which is difficult to meet market demand.In this paper,the optimal fermentation conditions and the optimal ratio of carbon,nitrogen and inorganic salts were investigated by single factor,orthogonal tests and response surface optimization method to optimize the deep liquid fermentation of Sanghuangporus vaninii,using nucleoside yield as an indicator.And the effect of adding different precursors and regulatory factor on the yield of nucleoside was also investigated.The optimal fermentation conditions were determined as follows:10%inoculum（V/V）,initial p H 7,incubation temperature 32℃,shaker speeds 140 r/min,and incubation time 5 days;The optimal medium ratios were follows:glucose 15 g/L,sucrose 20.00 g/L,peptone 5.00 g/L,beef paste 2.50 g/L,Mg SO₄ 1.00 g/L,Ca Cl2 1.50g/L,Zn SO₄ 1.00 g/L,Mn SO₄0.50 g/L;Optimal amount of precursor and regulatory factor:Adenine 1.55 g/L,Hypoxanthine 2.45 g/L,Sodium pyruvate 3.00 g/L,Quercetin0.15 g/L.Under the optimum conditions,the nucleoside yield of liquid fermentation of Sanghuangporus vaninii was 311.76±4.21 mg/L,34.6 times higher than that before optimization,which provided a theoretical basis for the further development and utilization of Sanghuangporus vaninii.In addition,the antitumor and antioxidant activities of nucleosides of Sanghuangporus vaninii which before and after the optimization of liquid fermentation process were compared.The results showed that the nucleosides of Sanghuangporus vaninii had good antitumor and antioxidant activities in vitro and the optimized nucleoside enriched products had better activities.The inhibitory IC₅₀ values of the optimized enrichment products on the Hep G2 and HGC-27 cells were 76.33±2.38μg/ml and 156.11±3.17μg/ml;The DPPH scavenging rate of 0.5 mg/ml was 69.7%;The ABTS scavenging rate was 73.7%.Therefore the optimization of fermentation technology not only increased the nucleoside production of Sanghuangporus vaninii but also improved its antitumor and antioxidant activities in vitro.To sum up,in this paper,the liquid fermentation process of Sanghuangporus vaninii was optimized,which made the nucleoside yield of Sanghuangporus vaninii increase by 34.6 times.The antitumor and antioxidant activities of its nucleosides in vitro were studied.It provided a theoretical basis for further utilization of Sanghuangporus vaninii.