Research Of The Recovery Method And Cryocryoprotective Agent During Lyophilizing In Vitro Produced Bacillus Popilliae

Scarabaeidae insect is currently a wide distributed and one of the most damaging pest species across the world. They feed on a wide range of plant roots such as those of grasses, agricultural and horticultural crops and trees. Although the traditional chemical prevention methods can control the population of the insects to some extent, it causes serious environmental pollutions. A new and harmless method is needed to control the insect.Bacillus popilliae is known to parasitically cause milky disease in the larvae of Scarabaeidae insects, eventually cause their death. It is an effective microbial insecticide to Scarabaeidae insects. The spores of Bacillus popilliae are also harmless to the environment and can remain viable (and infective) in the field for decades, providing controls effect during the subsequent pest generations or seasons after application. Thus, the bacillus popilliae was used as an effective microbiological insecticide to control the population of the Japanese beetles.This dissertation research is a continuation of the research in our laboratory, studying the methods to obtain spores from the culture medium and to control the conditions during the freeze-drying, therefore to identify the ideal composition of the productive agents that can mostly preserve the activity of the milky spores. The study shows diatomite is a good carrier to adsorb the spores from the liquid. Skim milk, fucose, glycerin and glutamic acid are good cryoprotective agents that can be used effectively to preserve the activity of the milky spores during freeze drying. The research can accelerate the development of microbial insecticides in China, and contributes to the sustainable development of Chinese agriculture.