Team of Biopesticides (LPIP), Centre of Biotechnology of Sfax, University of Sfax, Tunisia
Unit of biostatistics and Bioinformatics, Centre of Biotechnology of Sfax, University of Sfax, Tunisia.
Pol J Microbiol. 2013;62(3):287-93.
A multiple linear regression analyses were performed to screen for the significant factors simultaneously influencing production of deltaendotoxin, proteolytic activities and spore formation by a Bacillus thuringiensis kurstaki strain. Investigated factors included: pH of the medium, available oxygen and inoculum size. It was observed that oxygen availability was the most influencing setting on both deltaendotoxins production and spores counts, followed by initial pH of the medium and inoculum size. On other hand, pH of medium was found to be the most significant parameter for proteolytic activity, followed by inoculum size and dissolved oxygen. Our results suggested that the first order with two-factor interaction model seemed to be more satisfactory than simple first order model for optimization of delta-endotoxin overproduction. The coefficients of determination (R') indicated a better adequacy of the second order models to justify the obtained data. Based on results, relationships between delta-endotoxins production, proteolytic activities and spores counts were established. Our results can help to balance delta-endotoxins production and its stability.
采用多元线性回归分析筛选出同时影响苏云金芽孢杆菌 kurstaki 菌株 δ-内毒素、蛋白水解活性和孢子形成的显著因素。研究因素包括：培养基的 pH 值、可用氧和接种量。结果表明，氧气供应对 δ-内毒素的产生和孢子数的影响最大，其次是培养基的初始 pH 值和接种量。另一方面，发现介质 pH 值是蛋白酶活性的最重要参数，其次是接种量和溶解氧。我们的结果表明，与简单的一阶模型相比，一阶与两因素交互模型似乎更能满足 δ-内毒素过度产生的优化要求。决定系数（R'）表明二阶模型更能充分说明所获得的数据。基于结果，建立了 δ-内毒素产生、蛋白水解活性和孢子计数之间的关系。我们的结果有助于平衡 δ-内毒素的产生及其稳定性。
