Study On The Production Of Termite Active Metabolites By Endophytic Bacteria

Termites is a kind of social insects, which have a well-organized groups. As it have big harm to human’s lives, it was listed as one of the world’s five major pests. Use chemical termite control is still the most important and common means, but residual toxicity is serious, the environment and human health have posed great threat. Using non-toxic or low toxic pollution-free source of natural pesticides termite control will inevitably become termite control of the trend.Biological role of endophytic bacteria to host plants is receiving increasing attention, at present the biological role of the plant endophytic bacteria include: growth-promoting effect, biological nitrogen fixation and the role of plant disease resistance. Endophytic bacteria of plants produce a variety of secondary metabolites with the effectiveness of controling diseases and pests. By using of plant endophyte , microbial pesticide formulations or active ingredients of plant extract will be developed to control termite, which has broad potential applications.A strain of endophytic bacteria HUB-Ⅰ-107 was isolated from the North American termite-resistant cypress trees (Juniperus virginiana) and the United States cypress (Chamaecyparis lawsoniana) which has obvious termite killing effect, by bacteria identification , it was identify as a new species of Serratia-Serratia lawsoniana.The the experimental analysis of metabolites of the strain of the HUB-Ⅰ-107,by a large amount of fermentation and feeding termites experiment, indicated that the existence of effective substances of killing termites was in the cell but culture broth. by the initial physical and chemical analysis to the fermented product, the active substances for killing termites was polysaccharides. The extracts of capsular polysaccharide and lipopolysaccharide were separated and purified from the cell. Measured by the standard curve of glucose, capsular polysaccharide and lipo-polysaccharide contents were 39.2%, 70.8%, analysis of thin-layer chromatography to capsular polysaccharide and lipo-polysaccharide, the monosaccharide composition of capsular polysaccharide were xylose, mannose, glucose and galactose and other, those in the LPS were arabinose, mannose, glucose and galactose and others. Termites were fed with two kind of polysaccharides, experimental results showed that capsular polysaccharide have significant effect of killing Termites. LPS suppression is not significant. So the capsular polysaccharide is the active termiticide ingredient produced by endophytic bacteria.