Designing Matrix L18 Trials via Taguchi Model to Improve Performance of Trichosporon sp. Cas se5 in the Selenite Removal

Low selenium level is considered as an essential nutrient for humans and animals. However, selenium, in the form of selenite, is very toxic at high concentrations and leads to acute selenium poisoning (selenosis). The current project was done using the Taguchi method as an efficient, effective method, and without the need for a large number of experiments to optimize selenite removal.

The independent variables at three levels include: initial concentrations of selenite, biomass and NaCl, initial pH, and agitation. L18 orthogonal array was designed for these variables. The experiments were repeated three times and their mean amounts were analyzed using Qualitek-4.

The factors which had a significant impact on the selenite removal in order of importance were as follows: selenite ion (8 g/L), agitation (80 rpm), NaCl (2.5% w/v), biomass (40 g/L), and pH 6.8. Under optimal conditions in the selected levels of these factors, approximately 92.1% of selenite was removed after 48 h of incubation, at the 5% significance level (p< 0/05).

The current study is the first report of the successful application of the Taguchi method in the optimization of selenite removal under resting cells of Trichosporon sp. as biocatalysts. Therefore, the optimization techniques used in the present study can be proposed for the bio-remediation of contaminated environments.