The optimal temperature and initial pH for both mycelial growth and exopolysaccharide (EPS) production in shake flask cultures of Phellinus linteus KCTC 6190 were found to be 30 C and pH 4.0, respectively. Optimal medium composition was determined to be sucrose 50 g/l, corn steep powder 3 g/l, KH2PO4 0.68 g/l, and CaCl2 0.55 g/l. Under optimal culture conditions, the maximum mycelial biomass and EPS achieved in a 5-1 stirred-tank fermenter indicated 11 and 3.3 g/l, respectively. To the best of our knowledge, this is the highest polysaccharide yield amongst liquid cultures of P. linteus reported in the literature. The three groups of EPSs (designated as Fr-I, -II, and -III) were obtained from the culture filtrates by a gel filtration chromatography on Sepharose CL-4B and the different fractions were analyzed directly using the size exclusion chromatography coupled with multi-angle laser-light scattering (SEC/MALLS) analysis. It was revealed that all fractions of EPS were polysaccharides consisted of mainly mannose, galactose, and glucose. The molecular weights of Fr-I, -II, and -III of EPS were determined to be 433,400 (+/-7801), 31,470 (+/-283), and 12,950 (+/-90) g/mol, respectively. The SEC/MALLS analysis revealed that molecular dimension of the Fr-I was a spherical form, whereas the Fr-II was a random coil in an aqueous solution. (C) 2003 Elsevier Inc. All rights reserved.