Improvement of exo-polysaccharides production and modeling kinetics by Armillaria luteo-virens Sacc. in submerged cultivation

Abstract

Armillaria luteo-virens Sacc. is a special medicinal and edible mushroom in China, and its wild type has been investigated that it contains some functional components. The optimization of submerged culture conditions for mycelium growth and exo-polysaccharide (EPS) production in an edible mushroom A. luteo-virens Sacc. was studied in shake flasks and bioreactors with response surface methodology (RSM). A fractional factorial design (FFD) and central composite design (CCD) were applied to optimize the main factors that affect the fungal polysaccharides production in a submerged culture. Glucose is very important for EPS production by A. luteo-virens Sacc., and yeast extract powder also significantly affects fungal EPS production through fractional factorial experiment. The optimized cultivation medium constituents were derived from the predicted model using central composite design as follows: 31.26 g/l glucose, 1.06 g/l yeast extract powder, 1.00 g/l K 2HPO 4, 0.50 g/l KH 2PO 4, and 0.45 g/l MgSO 4·7H 2O, pH unadjusted. The predicted maximal EPS concentration was 5.40 g/l using the optimized culture medium compositions at 23 °C for 5 days. Additionally, the submerged cultivation process was explained using the optimized cultivation medium. The cultivation kinetics model constructed was suitably depicting the culture process in bioreactor cultivation scale.