Optimization of extraction and characterization of polysaccharides from medicinal mushroom Ganoderma lucidum using response surface methodology

Abstract

Submerged fermentation for the production of polysaccharides has received the greatest interest in recent years due to its increased demand as drug. Response surface methodology was employed to optimize the conditions for extraction of polysaccharides from Ganoderma lucidum. Central composite rotatable design was employed to optimize temperature, time, sodium hydroxide (NaOH) concentration and volume of NaOH for polysaccharide extraction. The various effects of the factors were studied by β-coefficient and Fischer's F-test for analysis of variance (ANOVA) and a second order model was developed. The results indicated that the optimum conditions were an extraction temperature of 100°C, an extraction time of 3 h, NaOH concentration of 6% and ratio of liquid to solid of 20 ml. The experimental polysaccharide production at predicted optimum conditions was 4.96% that validates the high degree of accuracy. Fourier transform infrared spectroscopy (FTIR) was used to obtain vibrational spectra of GL-2 mycelium and fruit body. The bands in the range of 1200 to 800 cm-1 indicated the presence of polysaccharides.