Refolding of recombinant proteins using polymer- salt aqueous two-phase system

The influence of pH, salt concentration, polyethylene glycol (PEG) molecular weight and concentration, enzyme loads and temperature on the enzyme refolding has been evaluated. To optimize and build the mathematical model and minimize the number of experiments for the design parameters, response surface methodology with a face-centered central composite design (CCF) was defined. The adequacy of the calculated model for the response was confirmed by means of variance analysis and additional experiments. Recovery of more than 99% active xylanase was obtained for a system with 18.3% (w/w) PEG 1000, 14.4% (w/w) phosphate at pH 8.5, and enzyme load corresponding to a protein concentration of about 0.05 mg/g system. The optimum temperature was found to be 22 º C.

Keywords:

Aqueous two-phase systems , Protein Refolding , Xylanase