苏云金芽孢杆菌NU-1、NU-2毒力提高与保护的研究

【作者】 王荣伟；

【导师】 郭爱莲；

【作者基本信息】 西北大学 ， 微生物学， 2004， 硕士

【摘要】 本实验研究了苏云金杆菌NU-1、NU-2毒力的提高与保护。 研究了NU-1、NU-2的菌种培养、种子培养，筛选了适宜的培养条件；出于工业化生产的目的，利用正交方法优化筛选了发酵培养基，并测定了晶体蛋白含量。结论为：菌种培养72h，采用1号种子培养基，4％接种量，种子培养7h，NU-1在2号、10号发酵培养基上，NU-2在4号发酵培养基上发酵结果最高。NU-1在2号培养基上发酵40h，菌数达85.5×10~8个／ml，pH8.2，晶体蛋白含量为6.320mg/ml，在10号培养基上的生长情况与其相似；NU-2在4号培养基上发酵42h，菌数达到78.0×10~8个／ml，pH8.1，晶体蛋白含量为6.085mg／ml。为了进一步研究NU-1、NU-2的生长情况，还测定了其生长和pH曲线。 筛选出两种添加剂，试验了它们对Bt发酵的影响。结果表明：添加剂1号和添加剂2号都能提高Bt的发酵菌数并缩短发酵时间。 采用不同防腐剂处理Bt制剂，研究了防腐剂的防腐效果。试验结果表明防腐剂1号，2号都是良好的防腐剂，防腐剂1号用量0.15％，防腐剂2号用量0.04％就可取得理想的防腐效果。 用SDS-PAGE、酶活测定、电镜观察等方法研究了紫外线照射对Bt的破坏，并初步探寻了保护方法。结果表明：紫外线照射能破坏晶体蛋白的表面结构和形态，照射24h后，酶活性几乎全部丧失，SDS-PAGE显示晶体蛋白几乎完全不溶。添加0.5％苋菜红做保护剂，再经紫外线照射后，酶活降低较小，电泳显示伴孢晶体碱溶产生的135KD和65KD原毒素蛋白几乎无变化，证明染料类是较好的保护剂。更多还原

【Abstract】 The main topic of the paper is the increase and protection of toxicity of two Strains , NU-1 and NU-2, of Bacillus thuringiensis.The culture of strains and seeds of NU-1, NU-2 was researched to screen out the suitable culture condition. The orthogonal experiment was tested to select the best fermentation medium. The crystal protein was purified and its density was measured. Result showed: when the No1 seed medium, the inoculation of 4%, 72 hours’ culture of strain and 7 hours’ culture of seed were used, the fermentation of NU-1 in No2 and No10 fermentation media were highest and fermentation of NU-2 in No.4 fermentation medium get the best effect. In No.2 fermentation medium of NU-1, the quantum reached 85.8 X 108/ml, and the density of crystal protein was 6.320mg/ml after 40 hours. The result of NU-1 in No. 10 fermentation medium was similar to No.2. In No4 fermentation media of NU-2, the quantum reached 78.0X108/ml, and the density of crystal protein was 6.085mg/ml after 42 hours. The curves of growth and pH were tested.Chemical additives were used to enhance the activity of Bt. The results indicated that No.l and No.2 additives both increased the quantum of strains and shortened the time of fermentation.Experiments were designed to treat Bt with different preservations. Results showed that No. 1 and No.2 restrained strongly the sprouting of spores and the growth ofBt within 0-96 hours.The Ultraviolet-mediated impairment and protection of NU-1 and NU-2 were studied by the means of SDS-PAGE, test of enzyme activities and SEM. Results showed: the morphology and surface of PC were damaged by UV rays; the activities of enzymes and the solubility of parasporal crystal were almost lost after 24h radiation. Bt suspension with 0.5% amaranth exhibited the good solubility and retained most activities of enzymes after UV radiation. It was proved that Bt suspension with amaranth showed strong anti-ultraviolet effect.更多还原