Culture Characteristics And Zinc&Manganese Tolerance And Accumulation In Mycelia Of Cordyceps Hawkesii

As a kind of edible and medicinal fungi, parasitic on Napialts hunanensis，Cordyceps hawkesii is similar with Cordyceps sinensis in the chemical constituentsand pharmacological effects, so Cordyceps hawkesii is valuable as a new kind of drugresources.To culture Cordyceps hawkesii mycelium in solid state fermentation andsubmerged cultuer, the medium and culture conditions were optimized. The effect ofdifferent concentrations of Zn and Mn on mycelial growth, Zn and Mn accumulationand distribution in the mycelian cell, changes of antioxidant enzyme activity andPeroxidation degree in submerged culture were investigated. Zn and Mn resistanceand accumulation mechanism in Cordyceps hawkesii were also discussed.1. Cultural characteristic in Cordyceps hawkesiiSix different kinds solid culture medium were compared to determined a suitableone. The optimum carbon source and nitrogen source were glucose and peptone insingle factor experiment. On the basis of the above, the orthogonal experiment wasdone to determined the optimum liquid culture medium in Cordyceps hawkesii. Thegrowth curve of Cordyceps hawkesii mycelium in submerged culture was finished.2. The zinc tolerance in Cordyceps hawkesii in submerged cultureLow zinc concentrations showed a promoting effect to the growth of mycelia inCordyceps hawkesii. But the mycelia biomass significantly reduced with theincreasing concentration of zinc. Cordyceps hawkesii hyphae show a strong toleranceto zinc up to zinc concentration in25g L-1. The mycelium cells can absorb andaccumulate zinc up to96.39mg g-1, achieved the standard of Hyperaccumulationplants of10000mg kg-1. Peroxidation product (MDA) and soluble protein (SP) inCordyceps hawkesii mycelium was first increased then decreased with zincconcentration increasing. Catalase (CAT), superoxide dismutase (SOD), peroxidase(POD) in different zinc concentrations showed there effects in antioxidative damage.Zinc ion in cells mainly concentrated in the non soluble fractions (93.68%-98.15%)such as cell wall, cell membrane, cell device and so on. Guanosine and adenosinecontent was negatively related to zinc concentration. The high resistance to zinc stressand the high ability to accumulate zinc under submerged culture suggest that Cordyceps hawkesii may be applied to the bioremediation, especially contaminatezinc polluted water.3. The manganese tolerance in Cordyceps hawkesii in submerged cultureLow manganese concentrations showed a promoting effect to the growth ofmycelia in Cordyceps hawkesii. But the mycelia biomass significantly reduced withthe increasing concentration of manganese. Cordyceps hawkesii mycelia can grow inmanganese concentration up to30g L-1. Catalase (CAT), superoxide dismutase(SOD), peroxidase (POD) in different manganese concentrations showed there effectsin antioxidative damage. In mycelial soluble fractions, manganese percentage wasvery low (7.21%-10.38%). It shows that soluble components plays a secondary rolein manganese accumulation. With manganese concentration increasing, guanosine andadenosine content in mycelium decreased.