Biosorption of malachite green by novel biosorbent Yarrowia lipolytica isf7: Application of response surface methodology

In this study we used a newly isolated Yarrowia lipolytica ISF7 strain with a unique capacity to remove malachite green from culture. The effects of operating parameters such as initial pH, dye concentration, temperature and time added on the MG biosorption were studied using response surface methodology, a total of 32 experimental runs were set and the experimental data fitted to the empirical second-order polynomial model of a suitable degree. The optimum biosorption conditions were determined as initial pH 7.0, temperature 25 degrees C, 24 h and 35 mg L-1 of MG concentration. The maximum adsorption capacity for biosorption was found around the pH range 6.5-7.5. Hence from the obtained results it is clear that the noxious dye removal percentage is very low in acidic pH below 5 and alkaline pH above 7.5. The adequate precision (AP) ratio of the models varies between 34.22 for %R MG, which is an adequate signal for the model. AP values higher than 4 are desirable, and confirm that the predicted models can be used to navigate the space defined by the CCD. The nature of biomass dye interactions was evaluated by FT-IR analysis and maximum MG removal (99.889%) was obtained under optimum conditions. (C) 2015 Elsevier B.V. All rights reserved.