Prabakaran G, Hoti S L
Vector Control Research Centre, Indian Council of Medical Research, Unit of Microbiology and Immunology, Indira Nagar, Gorimedu, Puducherry 605006, India.
Biologicals. 2008 Nov;36(6):412-5. doi: 10.1016/j.biologicals.2008.06.001. Epub 2008 Jul 25.
Bacillus thuringiensis var. israelensis, a gram positive, spore-forming bacillus, produces parasporal crystal protein during sporulation, which is toxic in the mosquito larvae gut. An efficient downstream processing method for separating the spore crystal complex (SCC) from the fermented broth of B. thuringiensis var. israelensis is required to achieve maximum mosquitocidal activity. The different downstream processing methods, viz., tangential flow ultra-filtration, continuous centrifugation and acid precipitation were compared for their efficiency in separating SCC from broth obtained from a pilot-scale fermentor (100 l capacity). Among the three downstream processing methods, tangential flow ultra-filtration yielded the maximum amount of biomass (53.3g/l), maximum number of spores (2.30 x 10(18)CFU/ml) and highest level of larvicidal activity (LC(50) 28 nl/ml) against Aedes aegypti Bora-Bora strain followed by continuous centrifugation and acid precipitation methods.
苏云金芽孢杆菌以色列变种是一种革兰氏阳性、能形成芽孢的杆菌，在芽孢形成过程中产生伴孢晶体蛋白，该蛋白在蚊虫幼虫肠道中具有毒性。为了实现最大的杀蚊活性，需要一种高效的下游加工方法，从苏云金芽孢杆菌以色列变种的发酵液中分离芽孢晶体复合物（SCC）。比较了不同的下游加工方法，即切向流超滤、连续离心和酸沉淀法，以评估它们从100升中试规模发酵罐获得的发酵液中分离SCC的效率。在这三种下游加工方法中，切向流超滤产生的生物量最大（53.3克/升），芽孢数量最多（2.30×10¹⁸CFU/毫升），对埃及伊蚊博拉博拉菌株的杀幼虫活性最高（LC₅₀为28纳升/毫升），其次是连续离心法和酸沉淀法。
