A Study On The Features Of A Cordyceps Sinensis Strain Qsun-1

Cordyceps Sinensis is a famous Chinese medicinal fungus that has many active ingredients such as cordycepin, cordyceps acid, and cordyceps polysaccharide, which have many pharmacological features. The natural Cordyceps Sinensis is grown in the special environment with a long growth cycle and low production. In this thesis, a strain of anamorph of Cordyceps Sinensis was isolated from a head of ghost moth larvae including fresh stroma of Cordyceps Sinensis and cultured. Methods for industry production were provided in order to substitute the natural Cordyceps Sinensis.In this thesis, the stroma and infected ghost moth larvae of Cordyceps Sinensis was cultured respectively and the germination rates of anamorphic Cordyceps Sinensis were compared. A strain was isolted from stroma and named as qsun-1. The colony morphology, micoscopic structure of qsun-1were observed and the temperature for optimum growth of qsun-1was determined depending on cocolony diameter. The optimal conditions of liquid fermentation for qsun-1were established in the single factor experiment and orthogonal test. The effect of carbon and nitrogen source and their concentrations as well as MgSO4, KH2PO4, and VB1concentration, pH, volume of inoculum and fermentation, and fermentation time on growth of qsun-1was studied. In the mean while, the growth characteristics of qsun-1in barley wort was observed, the effect of reducing sugar concentration, metal ions type and their concentrations, pH and fermentation time on growth of qsun-1was examined.The result showed that a strain was easier to isolate from the stroma with a higher germination rate than the infected ghost moth larvae of anamorphic Cordyceps Sinensis may be due to inhibition from the growth of other bacteria. The range of temperature for suitable growth of strain qsun-1was15～18℃in solid culture. After the strain qsun-1was cultured in1%beef PDA culture medium for10d, the colony measured30mm in diameter showing milk white in front was upheaved obviously with thick hyphae, but light yellow in rear. The hyphae were mainly featured with transparent, homogeneous, and septate tubular filaments in liquid cultured. The optimal liquid fermentation condition of qsun-1was1.5%sucrose,2.5% peptone,0.15%MgSO4,0.25%KH2PO4,0.04%VB1, pH7, fermentation volume60mL of250mL,3%inoculum,6days for fermentation. Under this optimal condition, the dry weight of qsun-1was18g-L-1and crude exopolysaccharide was1.0g·L-1. The optimal fermentation condition of barley wort for growth of qsun-1was6%sugar,0.2%KH2PO4, pH7.0,4days for fermentation. Under this optimal condition, the dry weight of strain qsun-1was20g·L-1.