苏云金芽孢杆菌生物杀虫剂发酵生产的影响因素及其工艺选择

Factors analysis and process selection for the production of Bacillus thuringiensis based biopesticides

化学杀虫剂的长期使用给生态环境造成了严重破坏,也使害虫种群的抗药性日益提高,生物杀虫剂以其"绿色环保"的特点引起人们的广泛关注。其中,苏云金芽孢杆菌(Bacillus thuringiensis)制剂是目前世界上产量最大、应用最广的生物杀虫剂。它对鳞翅目、双翅目、鞘翅目、螨类等许多有害昆虫有毒杀作用,而对人类、动物和农作物无害。长期以来,人们一直致力于苏云金芽孢杆菌发酵过程的研究,以期获得高毒效的生物杀虫剂产品。本文首先对苏云金芽孢杆菌发酵生产的各种影响因素进行了综合分析,将影响因素分为培养条件和培养基组分两类,得出最佳培养条件为温度:(30±1)℃,pH:7.0±0.1,搅拌速度:400～600r·min-1,通气量:1∶0.6～1.2(发酵培养基体积与每分钟通入空气的体积之比),接种时间:对数期初;最佳培养基配比为碳氮比:8～10∶1,无机盐含量:KH2PO4或K2HPO4为0.075%～0.2%;MgSO4·7H2O为0.075%～0.3%;CaCO3为0.075%～0.15%;MnSO4·H2O、FeSO4·7H2O各为0.002%。其次,对当前研究与工业化生产中的各种发酵工艺进行了评述,总结了现有发酵工艺的优缺点。在现有研究基础上,降低培养基原料成本、改进发酵工艺和采用基因学手段构建高效工程菌株将成为未来研究热点。

The long-term use of chemical pesticides has caused serious damage to the ecological environments and raised the drug resistances for pest population. Biopesticides have attracted people’s widespread attention because of their eco-friendly properties. Bacillus thuringiensis （Bt） is such a biological agent, which is the most yield and most widely used to control the variety of pests. Bt is toxic to certain target pests such as： Lepidoptera, Diptera, Coleoptera and Mite pests, and poses no harm to human, animals or plants. The fermentation process for Bt harvesting was widely discussed to increase the toxicity of Bt in the past decades. Previous research showed that the growth and metabolism of Bt were affected by many factors that could be summaried as culture conditions and media components. The optimum culture conditions were determined to be temperature （30±1）℃ , pH 7.0±0.1, agitation speed 400～600 r·min-1, air supply 1：0.6～1.2 （litre of air/litre of fermentor content per minnte）, inoculation time： at the beginning of the logarithmic phase. For the culture media components, the optimum carbon / nitrogen ratio was 8～10：1, and percents of the inorganic chemicals were 0.075%～0.2% for KH2PO4 or K2HPO4, 0.075%～0.3% for MgSO4·7H2O, 0.075%～0.15% for CaCO3 , and 0.002% for MnSO4·H2O、FeSO4·7H2O. The advantage and disadvantage of typical fermentation technologies were also discussed for various processes selections at lab scale and industrial scale. The future researches should be focus on the reducing cost of culture media components, modifying the fermentation processess, and setting up the efficent strain with genic methods.