Optimization of magnetosome production by Acidithiobacillus ferrooxidans using desirability function approach

Present study aimed to resolve the conflict between cell growth and magnetosome formation of Acidithiobocillus ferrooxidans (A. ferrooxidans) in batch experiments by applying response surface methodology (RSM) integrated a desirability function approach. The effects of several operating parameters on cell growth (OD600) and magnetosome production (C-mag) were evaluated. The maximum overall desirability (D) of 0.923 was achieved at iron concentration of 125.07 mM, shake speed of 12237 rpm and nitrogen concentration of 2.40 g/L Correspondingly, the OD500 and C-mag were 0.522 and 1,196, respectively. The confirmation experiment confirmed that the optimum OD600 and C-mag obtained were in good agreement with the predicted values. The inductively coupled plasma atomic emission spectrometer (ICP-AES) and transmission electron microscopy (TEM) analyses revealed that the production of magnetosomes could be improved via optimization. X-ray diffraction (XRD) showed the magnetosomes are magnetite. Results indicated that RSM with a desirability function was a useful technique to get the maximum OD600 and C-mag simultaneously. (C) 2015 Elsevier B.V. All rights reserved.