Optimization of Selenite Removal by Lactobacillus sp. Tra cheese 6 Using Box-Behnken Design

Background & Aims: High concentrations of selenite have carcinogenetic, cytotoxic and genotoxic effects. Therefore, removal of this toxic pullutant from the environment has a particular importance in maintaining public health. In this study, with the aim of optimization of selenite removal process, the design Box-Behnken method was used to estimate the simultaneous effect of variables on removal efficiency and to determine the optimal values of variables on selenite removal with the probiotic bacterium Lactobacillus sp. Tra Cheese 6 Methods: An experimental method using a three-level Box-Behnken method fortesting the effects of four factors including concentrations of selenite ion, cell biomass, NaCl and agitation was investigated. Statistical Data Analysis was performed using Analysis of Variance (ANOVA) method. Regression coefficients of the second-order polynomial model were estimated. Then, by integrating the results and drawing a multivariate quadratic equation, the optimal point was precisely determined. Design-Expert software was used for data analysis. Results: Optimum removal of selenite was obtained at initial concentration of Selenite 49.5 mM, biomass concentration of 56 g/l, NaCl concentration of 4.2 % (w/v) and agitation at 100rpm. Under these conditions, the optimal selenite removal was 77.12 % after a 24-h reaction under the resting cells of Lactobacillus sp. Tra Cheese 6. Conclusion: In the current study, Response Surface Methodology based on Box-Behnken design was successfuly applied for improving selenite removal with the probiotic bacterium Lactobacillus sp. Tra Cheese 6.