The optimization of submerged culture conditions and nutritional requirements was studied for the production of exopolysaccharide (EPS) from Agrocybe cylindracea ASI-9002 using the statistically based experimental design in a shake flask culture. Both maximum mycelial biomass and EPS were observed at 25 degrees C. The optimal initial pH for the production of mycelial biomass and EPS were found to be pH 4.0 and pH 6.0, respectively. Subsequently, optimum concentration of each medium component was determined using the orthogonal matrix method. The optimal combination of the media constituents for mycelial growth was as follows: maltose 80 g/l, Martone A-1 6 g/l, MgSO4 center dot 7H(2)O 1.4 g/l, and CaCl2 1.1 g/l; for EPS production: maltose. 60 g/l, Martone A-1 6 g/l, MgSO4 center dot 7H(2)O 0.9 g/l, and CaCl2 1.1 g/l. Under the optimal culture condition, the maximum EPS concentration achieved in a 5-1 stirred-tank bioreactor indicated 3.0g/l, which is about three times higher than that at the basal medium. (c) 2004 Elsevier Ltd. All rights reserved.