抗紫外线降解苏云金芽胞杆菌微胶囊剂的制备工艺

Microcapsulation Formulation of Bacillus thuringiensis for Protection against Ultraviolet Radiation Induced Inactivation

选择邻苯二甲酸醋酸纤维素(CAP)为囊材,以苏云金芽胞杆菌(Bt)原粉为囊芯,探讨添加紫外线吸收剂后制备Bt微胶囊剂的工艺条件,并用生物测定的方法进行Bt微胶囊剂抗紫外线降解能力比较。结果表明,Bt微囊剂加工的最佳工艺条件为:Bt原粉/CAP/紫外线吸收剂=100/40/3,pH值3.5左右,温度25℃。生物测定结果表明,经紫外线照射处理后,Bt原粉效价活性保留率为30.7%,以CAP为囊材包被的Bt微胶囊剂效价活性保留率为54.8%,抗紫外线降解能力比Bt原粉提高约24%;以CAP为囊材,添加2种不同的紫外线吸收剂包被的Bt微胶囊剂,其中防效最佳的配方组合效价活性保留率为86.9%,抗紫外线降解能力比Bt原粉提高约56%。

In order to protect Bacillus thuringiensis （Bt） insectcide against inactivation caused by ultraviolet radiation,a study was carried out on how to pack the Bt crystals and spores mixtures into microcapsule, with CAP（cellulose acetate polymer） and UV absorber as encapsulation materials and protection reagent. The appearance, average diameter, suspension ability, and rate of inwrapping were checked. The best conditions for encapsulation were Bt/CAP/UV absorber= 100/40/3, at temperature 25 ℃,with pH 3.5. The effect of microcapsulation on the UV resistantance was investigated by the toxicity bioassays againstPlutella xylostella. The toxicity of the samples preserved was 30.7% （Bt powder as control）, 54.8% （encapsulated only with CAP） and 86.9% （with CAP and UV absorber） respectively. After encapsulation, the UV resistance was 24 % （only with CAP） and 56 % （with CAP and UV absorber） higher than the control.