Optimization of bioinsecticides overproduction by Bacillus thuringiensis subp kurstaki using linear regression.
Karim Ennouri, Hanen Ben Hassen, Nabil Zouari Pol J Microbiol 2013; 62 (3): ICID: 1072794 Article type: Original article IC™ Value: 10.00
Abstract provided by Publisher
A multiple linear regression analysis was conducted to screen the significant factors influencing simultaneously production of delta-endotoxin, proteolytic activities and spores formation by an isolated strain of Bacillus thuringiensis kurstaki. Factors investigated were pH of the medium, available oxygen and inoculum size. It was observed that available oxygen was the most influencing setting on twice delta-endotoxins 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. This is interesting to balance delta-endotoxins production and their stability. In this study, analysis of obtained 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 (R²) 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.