Optimization of chitosan/activated charcoal-based purification of Arthrospira platensis phycocyanin using response surface methodology

Abstract

In the present paper, a mild and rapid purification method for phycocyanin from Arthrospira platensis was optimized by multi-objective response surface methodology. The independent variables were chitosan content (0.1–0.5% w/v), activated charcoal content (3–15% w/v), and stirring time (2–18 min). Under the optimum conditions (i.e., 0.24% w/v chitosan, 8.4% w/v activated charcoal, and 10.2 min stirring time), the maximum phycocyanin purity and concentration of 3.14 ± 0.12 and 0.27 ± 0.01 mg mL−1 were attained, respectively, which were in fact 1.67-folds and 1.17-folds higher than those obtained by the conventional method, i.e., ammonium sulfate precipitation. The phycocyanin purity recorded in this study met the purity requirements considered for reactive grade. Moreover, higher antioxidant activity and fluorescence intensity were recorded for the phycocyanin purified by chitosan and activated charcoal vs. the conventional method. It was also found that antioxidant activity and fluorescence intensity of phycocyanin exhibited a direct relationship. The maximum phycocyanin stability was observed at pH 8 and temperature values < 45 °C. Additionally, the stability was gradually diminished under alcohol and light stresses. Conclusively, the phycocyanin obtained by the method developed herein possessed a considerable purity and concentration with noteworthy functional properties.