Bt杀虫晶体蛋白-肠溶性微囊制备方法的初步研究

采用双乳液法研制苏云金芽孢杆菌(Bacillus thuringensis，简称Bt)晶体蛋白的肠溶性微胶囊，并应用L16(45)正交试验设计研究了相关因素对微胶囊包封率的影响。结果表明，5个因素对包封率均有显著影响，影响大小依次为芯材乳化程度>Bt晶体蛋白浓度(芯材)>HPMCP浓度(壁材)>蓖麻油浓度(助剂)>甲基纤维素浓度(亲水胶体)。以500 mL 分散系为条件，筛选出的肠溶性微胶囊较佳工艺为：芯材乳化转速6000 r/min， 20% Bt晶体蛋白溶液1mL，6% HPMCP溶液 50mL，分散系中含0.4% 蓖麻油和2.2-2.5%甲基纤维素钠。按此种较佳组合制备微胶囊，对Bt晶体蛋白的包封率在85%左右，微囊直径约为20.7 μm，在pH 8.5 的碱性缓冲液中可在5分钟内崩解，释放出Bt晶体蛋白。

Studies on the preparation technology of enteric microcapsule of insecticidal crystal proteins from Bacillus thuringensis by orthogonal matrix method

OBJECTIVEThe paper aimed to research the preparation technology of enteric microcapsules of insecticidal crystal proteins(ICP) of Bacillus thuringensis(Bt).MethodDouble emulsion method was used for the effort to prepare enteric microcapsules with ICP as core material and hydroxypropyl methylcellulose phthalate(HPMCP) as shell material.Experiment in orthogonal matrix design L16(45) was used to value the influence of the relevant elements.ResultsEnteric microcapsules wrapping ICP could be prepared by double emulsion method.The encapsulation of ICP was influenced by factors such as emulsification rotation speed, concentration of shell and core materials, emulsification agent and hydrocolloids, which were listed in a pattern of decreasing importance.In 500 ml aqueous medium for formation of the microcapsules, the optmal technology was to emulsify 1 ml 8.6mg/mL IPC, 50ml 20mg/mL HPMCP and 2 ml castor oil at emulsification rotation speed of 6000 r/min, then disperse the emulsion in 2.1% or 3.3% carboxymethyl cellulose(CMC-Na).