摘要
通过以棉铃虫4龄幼虫为供试昆虫的生物测定,对从新疆兵团145团棉田自然死亡棉铃虫体内分离筛选到的一株高效苏云金杆菌(Bacillus thuringiensis,Bt)菌株35,进行了发酵工艺的初步研究。对Bt菌株35进行了摇瓶发酵和小试发酵,利用2L全自动发酵罐优化了发酵培养基和操作条件。优选培养基的组分为:棉籽饼3.25%、玉米粉1.4%、麸皮1.2%、KH2PO40.11%、FeSO40.0049%,该培养基与对照培养基相比,发酵液含菌数高达40.8×108cfu/mL,比对照培养基提高了63.7%,发酵液毒力高达66.1%,比对照培养基提高了81.5%。利用CaCO3调节pH值,可使活菌数提高37%,发酵周期缩短9 h;28℃发酵活菌数比30℃增加12.1%,发酵时间延长3h,最适发酵产孢温度为30℃;以芽孢接种,其发酵时间比营养体接种延长3 h,最优接种方式为营养体接种;溶氧对发酵有较大的影响,当发酵全程采用1∶0.8 vvm的通气量时,最终发酵菌数为38.1×108cfu/mL;当发酵前期、中期、后期的溶氧分别为1∶1.0 vvm、1∶1.4 vvm及1∶1.2 vvm时,活菌数可达72.5×108cfu/mL,发酵水平提高约1倍。对Bt发酵液进行生物测定,发酵原液(Bt离心沉淀物+上清液)的LC50比去掉上清液的沉淀物提高了37.1%,说明上清液能提高发酵液的毒力。
A high effect of Bacillus thuringiensis 35 strain was isolated and screened from natural death bollworm in No. 145 BINGTUAN in Xinjiang. And the manufacting technique of Bacillus thuringiensis 35 strain was studied. The fermentation culture medium and the fermentation technique was had been optimized by shaker and small fermentor. The orthogonal design has been developed for the superior experiment of 35 strain, s fermentation media and cultural condition by shaking flasks. The formulas of medium shows higher production than original fermentation medium. The production of spore and bacteria was 63.7% higher than original fermentation medium in shaker of fermentation. The optium fermentation medium （%） was obtained which was composed of contton-seed cake 3.25, corn flour 1.4, wheat bran 1.2, potassium dihydrogen phosphate 0.11, ferrous sulfate 0. 0049. Compared with contrast media,the concentration of superior media reached 40.8 ×10^8 cfu/mL, increased 63.7% ; the potency of superior media reached 66.1%, increased 81.5%. The fermentation media is characterized by green environmental protection and this locality and ecology and economy and society. A high effect of Bacillus thuringiensis 35 strain was tested in 2L automatic fermentor. Calcium carbonate regulates the pH values of fermentation culture medium and raises fermentative bacteria and spore 11% ,and shorten fermentation period 4h. Under the cultural temperature 28℃ over 30℃, the production of toxic potemcy was 12.1% higher under the culture conditions of temperature 30℃. The fermentaion time was prolonged for 3 hours by gemma inoculation than trophozoite inoculation. We have reached the most suitable temperature 30℃ and optimum inoculation way for bacterial nutrition body. Solvation oxygen pOe has much effect to fermentation. With ventilation volum 1 ： 1.0 （liter/ min, the production of toxic potency was 38.1×10^8 cfu/mL. In fermentation prophase ,metaphase, anaphase solvation oxygen pO2 with ventilation volum 1 ： 1.0 （liter/min）, ventilation volum 1 ： 1.4 （liter/min）, ventilation volum 1 ： 1.2（liter/min）sepreately, the production of toxic potency was 72.5 × 10^8 cfu/mL. It showed that the fermentation supernant has increased toxicity of fermentation production. Through the production of fermentation determined by biossay, LC50 of fermentation production has increase 37.1% than centifugal concentrate.
出处
《西北农业学报》
CAS
CSCD
北大核心
2008年第1期53-57,共5页
Acta Agriculturae Boreali-occidentalis Sinica
关键词
苏云金芽孢杆菌
发酵影响因子
Bacillus thuringiensis
Fermentation factor of influence
