Study On Liquid Fermentation Culture And Anti-fatigue Activity Of Grifola Frondosa

With unique flavor,rich nutrition and physiological functions,Grifola frondasa is become more and more popular in recent years.In order to develop and utilize Grifola frondosa,we have studied the types and concentrations of food-grade nitrogen sources suitable for the liquid fermentation.At the same time,we have studied the optimum culture conditions of 7L stirred fermentor,and compared the performance of stirred fermentation tank and airlift fermentation tank,and have carried out semi-continuous fermentation.In addition,we also determine the active ingredients in the fermentation broth and mycelia,and research the anti-fatigue effect of the fermentation broth.In this experiment,the type and concentration of food grade nitrogen source in the medium are optimized in 500 mL shake flask.When the medium are added 0.4%Angel peptone FP102,the biomass and extracellular polysaccharide content of Grifola frondosa are the highest,which reach 3.853 g/L and 0.445 g/L.The optimum culture conditions of the 7 L stirred fermentation tank were as follows:culture temperature 23?,stirring speed 120 r/min,ventilation volume 3 L/min.And the optimum culture conditions of seed broth in the shake flask were as follows:the magnetic stirring 14 min under 500 r/min.By comparing the performance of different fermentation equipment,it is concluded that the 7 L stirred fermentation tank is more suitable for the fermentation of Grifola frondosa than the 7 L airlift fermentation.The biomass and extracellular polysaccharide content produced in the 7 L stirred fermentation tank were 33.228 g and 10.419 g,which were 16.944 g and 3.013g in the 7L airlift fermentation.the mycelium pellet produced by 7 L stirred fermentation tank is light yellow,but which produced by 7 L airlift fermentation is white and yellow.Also the mycelium pellet produced by 7L stirred fermentation tank has an uniform size,smaller diameter,and higher density than produced by 7 L airlift fermentation.In addition,the fermentation broth produced by 7 L stirred fermentation tank is light yellow which has a rich flavor but the fermentation broth in 7 L airlift fermentation is brown and bad smell.The results of semi-continuous fermentation of Grifola frondosa showed that semi-continuous fermentation is beneficial to maintain the activity of mycelium,increase the biomass and shorten the cycle of fermentation.However,with the increase of fermentation time,the hyphae of the core of mycelium pellet were self-dissolving,and then the mycelium pellets were broken,which reducing the production of extracellular polysaccharides.The content of extracellular polysaccharide in the broth is 3.541 mg/mL,and the content of intracellular polysaccharide in mycelium is 82.112 mg/g.The content of protein in the broth is 0.014 mg/mL,and the content of protein in mycelium is 0.491 mg/g.The content of flavonoid in the broth is 0.026 mg/L,and the content of flavonoid in mycelium is 33.412mg/g.The content of polyphenol in the broth is 0.098 mg/mL,and the content of polyphenol in mycelium is 87.024 mg/g.Running cage experiments and swimming experiments showed that the Grifola frondosa fermentation broth had the anti-fatigue activity,which could improved the athletic ability and endurance of mice,and had no effect on the growth and development of mice.The the same experiments were carried out to verify the supernatant of diluted brothcan significantly increase the number of mouse laps and prolong the swimming time of mice,which is 174.75 r?193.25 r?184.25 r?170 r and 961.75 s?1068.5 s?1091.25 s?1030 s,and the extension rates of the swimming time were 27.76%?41.97%?44.89%?36.79%.