Screening of potential bacteria from soil sample for methylene blue dye degradation: RSM modelling and optimisation

This study aimed to screen the bacteria from the samples collected from textile dye enriched soil. Twenty-one soil bacteria were isolated and examined for their efficacy for methylene blue (MB) decolourisation. Bacillus cereus found to be the potential microorganism for MB decolourisation, characterised using 16S rRNA sequence technique. Response surface methodology (RSM) was employed to optimise the three independent variables like dye concentration (mg/L), pH and glucose concentration (g/L) for decolourisation of MB. The experimental run given by central composite design (CCD) with quadratic model was conducted used in this study to optimise the variables and fit the model. The analysis of variance (ANOVA) showed; R2 = 0.9992 and R2adj = 0.9985, which confirmed that experimental and predicted response are in good agreement and the model is highly significant. The optimal values of dye concentration (mg/L), pH and glucose concentration (g/L) proposed by RSM were found to be 70, 7.88 and 3.33, respectively.