Study On Biotransformation Of Insect Pest, Dendrolimus Punctatus By Medicinal Fungus Ganoderma Sinense

Dendrolimus spp. is one of the serious insect pests in China, however, it is rich in nutrition materials, and has a great amount of wild resource. Ganoderma sinense is a precious medicinal fungus with a variety of important pharmacological activities, and can be cultivated by various substrates owing to its rich enzyme systems with strong activity. Therefore, it is highly important both in theory and practice for biotransformation of the pest Dendrolimus spp. by Ganoderma sinense.The biotransformation modes of D. punctatus by G. sinense was studied on the basis of previous study in our lab, and then the fermentation conditions and kinetics was further explored, Changes in the composition of G. sinense polysaccharide was researched as well. The main results are as follows.1. G. sinense could grow normally in the media when adding different concentrations of pupa powder of D. punctatus and its water and petroleum aether extracts, whereas the pupa powder showed better effects both on mycelium biomass and polysaccharide production of G. sinense than the other two, and the optimum fermentation culture medium was composed of 24 g/L Glucose,10 g/L pupa powder, 2.5 g/L peptone,1.5 g/L KH2PO4,0.75 g/L MgSO4,0.01 g/L VB1.2. An orthogonal design L9 (33) were applied to optimize the biomass and polysaccharide fermentation, with inoculation amount, seed age and additive concentration of pupa powder were key factors. The experimental results showed that the optimal fermentation culture condition for biomass production was inoculation amount 8 g/L, seed age 6 days, pupa powder amount 8 g/L; while the culture condition for polysaccharide production was inoculation amount 10 g/L, seed age 6 days and pupa powder concentration 10 g/L.3. Kinetics models and their parameters of cell growth, polysaccharide production and substrate consumption of biotransformation process were obtained with Sigmoid model fitting by analyzing the partial fermentation process, and kinetics parameters of fermentation process were also solved and analyzed, which showed that the models coincide with experimental data.4. G. sinense polysaccharide was separated by DEAE-cellulose column, the detecting results showed that there was no new polysaccharide composition found when adding pupa powder or not. Both the two samples had four main compositions, among which, PS-1 had the highest content, followed by PS-4. These results suggested the synthetic pathway of G. sinense polysaccharide was not affected by addition of pupa powder.The study proved the feasibility of biotransformation of the pest D. punctatus by G. sinense, and the pest might be a new culture medium for fermentation of G. sinense, and a new exploration model of D. punctatus were put forward in this dissertation.