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题名	苏云金杆菌固态发醇过程优化及粉剂湿润性的研究
作者	朱玮
学位类别	硕士
答辩日期	2004
授予单位	中国科学院过程工程研究所
授予地点	中国科学院过程工程研究所
导师	赵兵
关键词	苏云金杆菌 固态发酵 润湿时间
其他题名	Process Optimization of Solid-state Fermentation and Improvement of Soakage of Bt Powder
学位专业	生物化工
中文摘要	本文较系统地研究了苏云金芽抱杆菌固态发酵的生长特点、培养基配方和发酵条 件的优化、发酵产品的干燥过程以及粉剂湿润性的改善等，为苏云金杆菌的大规模固 态发酵提供参考。首先建立了苏云金杆菌固、液态的细胞芽抱生长曲线，摸索了在发酵过程中还原 糖的代谢变化，并对固、液态的发酵进行了比较。同液态相比，固态一级发酵的周期 较长，但是固态培养基的营养丰富，没有还原糖的消耗低谷。在此基础上，通过正交 实验对Bt固态一级发酵进行优化，优化后的培养基为：76.4％鼓皮，12.7％花生饼粉， 8.9％米糠，1.9％Cao，0.05％KH2PO4，0.05％FeSO4。最佳发酵温度为30℃，0.7vvm 的连续通风条件下最佳初始含水量55％，1.75vvm条件下最佳初始含水量60％。结合工业生产的实际，进行Bt固态二级发酵的全过程优化和调控。以细胞数为 优化响应值得到一级液态种子液扩大培养的配方和操作条件：玉米粉2％，花生饼粉 1.67％，玉米浆1％。最佳培养pH7.4，转速180r/min。改进了盘式发酵，采用上下通风 的筛式网盘发酵，并通过单因素平行实验优化了该液体种子条件下的固态培养基：鼓 皮60％，花生饼粉30％，CaO1.5％，米糠8.5％。最佳发酵条件：初始含水量68.3％， 菌龄6hr-7hr，接种密度为4.15*106cells／g。并提出了苏云金杆菌变温发酵的工艺， 即在发酵的8hr-11hr，对数期开始时的3hr采用27℃的变温发酵，实验证明有利于 芽抱的生长。通过分析温度、通风对干燥过程的影响，得到干燥的适宜条件是60℃ 下通风干燥。采用优化后的结果进行固态发酵得到效价为27000IU／mg的产品，达到 优质产品的要求，在目前国内外固态发酵的同类培养基原料的正式报道中最高。首次 研究了芽孢数、杀虫蛋白含量、毒力效价三者之间的数值关系，建立相应的经验模型，验证结果也得到了较好的拟合。生物反应器技术是Bt固态发酵在工业规模取得高发酵水平的关键之一。首次在 1m3往复式搅拌发酵机（CHF-20）内进行了Bt发酵的初步实验，发酵产品的毒力效 价可达到2200OrU／mg。首次针对Bt固态粉剂的湿润性进行了研究。采用在发酵结束产物中加入表面活性剂、以无机材料为发酵培养基、部分加入无机材料改善培养基的方法分别展开实验。实验结果显示加入8％-10％表面活性剂188A或5.5％表面活性剂1080可以有效地控 制润湿时间。采用玉米粉25％、米糠10％、花生饼粉20％、CaO1％、无机载体IC031 44％的新型培养基发酵，可以在大幅改善润湿性的同时发酵结果也达到17500IU／nlg， 超过国家优质产品标准。在数皮培养基内直接加入10％的无机载体IC031，则不仅缩 短润湿时间，而且将底物利用率提高了约7倍。
英文摘要	The characteristics of the solid-state fermentation (SSF) of Bacillus thuringiensis, the optimization of medium and fermentation condition, the drying process of the fermentation product and improvement of soakage of the Bt powder were investigated. At first, Bt cell growth curve, spore number curve and reducing sugar curve either in submerged fermentation (SMF) or in single stage SSF were illustrated. Compared with SMF, the fermentation period of single stage SSF was relatively long, but there was no shortage of reducing sugar due to enough nutrients in the medium. Based on the results above, the optimum medium of Bt single stage SSF was obtained by orthogonal experiment: wheat bran 76.4%, peanut powder 12.7%, husk 8.9%, CaO 1.9%, KH2PO4 0.05%, FeSCU 0.05%. The optimum temperature is 30°C. The optimum initial water content was 55% when the ventilation quantity was 0.7vvm and 60% when the ventilation quantity was 1.75vvm. According to industrial process, the regulation of bi-staged Bt SSF process was carried out. The optimum liquid medium associated on Bt cell number was composed by 2% maize flour, 1.67% peanut powder and 1% corn steep liquor. The medium pH was 7.4 and the rotation speed of shakers was 180r/min. The optimum solid medium composition for Bt fermentation in the sieve was determined: wheat bran 60%, peanut powder 30%, husk 8.5%, CaO 1.5% and initial water content 68.3%. The age of inoculum was 6hr~7hr. The inoculum density was 4.15><106cells/g. The concept of temperature — changed fermentation was presented. After 8-10 hr fermentation, temperature was reduced from 30°C to 27°C and kept for 3 hours, which was benefit to spore formation. The drying process for Bt product was studied and optimized. The optimal drying temperature was 60°C, at which the process could be shortened by ventilation. After the regulation, the toxin titer of Bt products reached 27000IU/mg. For the first time, the relationship between spore number, ICP and toxin titer was studied and the empirical correlation for these factors was established. Bioreactor technology is regarded as a key factor for high toxin titer of Bt SSF. Bt solid-state fermentation was first examined in a lm3 reciprocatingly stir —red solid fermenter(CHF-20) and the toxin titer of Bt product reached 22000IU/mg. To overcome poor wettability of Bt powder, a comprehensive study was carried out for the first time. Three methods were used to improve the wettability, i.e.: the addition of surfactant to product, replacement of wheat bran by inorganic material and partial addition of inorganic material to the wheat bran medium. Adding 8% —10% surfactant 188A or 5.5% surfactant 1080 to the product was effective. Medium composed of maize flour 25%, husk 10%, peanut powder 20%, CaO 1% and inorganic carrier IC031 44% enhanced not only the wettability, but also toxin titer of Bt products which reached 17500rU/mg. The direct addition of 10% carrier IC031 to the medium with wheat bran reduced wetting time as well as increased utilization ratio of substrate by seven times than before.
语种	中文
公开日期	2013-09-16
页码	100
内容类型	学位论文
源URL	[http://ir.ipe.ac.cn/handle/122111/1393]
专题	过程工程研究所_研究所（批量导入）
推荐引用方式 GB/T 7714	朱玮. 苏云金杆菌固态发醇过程优化及粉剂湿润性的研究[D]. 中国科学院过程工程研究所. 中国科学院过程工程研究所. 2004.

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