1 Pak. J. Phytopathol., Vol. 23(1): 1-4, 2011. SELECTION OF CULTURE MEDIUM FOR EXOPOLYSACCHARIDES PRODUCTION BY CORIOLUS VERSICOLOR Shakil Ahmed*, Anila Anwar*, Azeem Haider*, M. Adnan Saeed*, M. Nadeem**, Zahida Nasreen** and Shahjahan Baig** *Institute of Agricultural Sciences, University of the Punjab, Quaid-e-Azam Campus Lahore **FBRC, PCSIR Laboratories Complex, Lahore ABSTRACT Coriolus versicolor is a medicinal fungus producing exopolysaccharides (EPS). Six well-defined culture media were studied to select the medium that maximizes production of EPS by Coriolus versicolor. Dry mycelial weight, reducing sugars and EPS concentrations of the broth were followed during fermentations. The yeast malt extract medium (YM) was shown to yield the highest production of EPS while the dry mycelial weight and reducing sugars were found maximum in Tien and Kirk medium (Tak). The initial glucose concentration was found to be the most important factor in EPS production and also cell growth. Keywords: Culture media, optimization, exopolysaccharides, Coriolus versicolor, glucose. INTRODUCTION During the past decades there has been an increasing interest in the production of exopolysaccharides (EPS) from mushrooms due to their various physiological activities (Kim et al. 2005). Most polysaccharides produced by fungi possess biological and pharmacological activities. Various fungi have been described to produce this type of EPS, such as Paecilomyces japonica (Sinha et al. 2001), Cordyceps militaris (Park et al. 2002), Tremella species (Khondkar et al. 2002) and Auricularia polytricha (Yang et al. 2002) among others. Coriolus versicolor, belonging to the Basidiomycetes class, can produce both extracellular and intracellular polysaccharides that have received special attention due to their physiological and biological activity. These fungi are well known as a medicinal mushroom in traditional therapeutic practice in Japan, China, Korea and other Asian countries (Cui and Chisti, 2003). Their polysaccharides have shown antitumour activity and include protein-bound polysaccharides extracted from the fungal mycelium like the Krestin and Polysaccharopeptide (Ng, 1998) and the extracellular polysaccharide Coriolan (Miyazaki et al., 1974). Most of the reported studies have focused on polysaccharides isolated from the mycelium. However, a few studies on EPS from C. versicolor in submerged culture have been reported (Kim et al. 2002). Although a number of works have attempted to obtain the best culture conditions and EPS characterization from different fungi, the effect of medium composition on C. versicolor fermentations which are important parameters to EPS production, remain relatively unexplored. This study is an attempt to formulate suitable production media for the production of mycelial biomass and EPS in C. versicolor. To the best of knowledge, this is the first report concerning the effects of cultural media on the production of cell biomass and EPS by submerged fermentation of C. versicolor from Pakistan. MATERIALS AND METHODS Microorganism and Culture media: Coriolus versicolor provided by Dr. John O Reid, National Research Council of Canada, Prairie Regional Laboratory, Saskatoon and Saskatchewan, Canada. The stock culture was maintained on slant and Petri dish with Tien & Kirk medium (Tien and Kirk, 1988), incubated at 25 0 C±2 0 C, stored at 4 0 C. Six media were used to evaluate the optimum production of extracellular and intracellular EPS from Coriolus versicolor. 1) Trametes defined medium (TDM): Glucose 9 g l -1 , glutamine 0.78 g l -1 ; NaCl 0.28g l -1 ; KH 2 PO 4 0.68g l -1 ; MgSO 4 .7H 2 O 0.25g l -1 ; thiamine 0.81 mg l - 1 and one ml of element solution. Element solution: FeSO 4 .7H 2 O 20 μM; CuSO 4 .5H 2 O 2 μM; ZnCl 2 5 μM; MnSO 4 .H 2 O 20 μM; CoCl 2 .6H 2 O 6 μM; NiCl 2 .6H 2 O 0.1 μM and (NH 4 ) 6 MO 7 O 24 .4H 2 O 0.5 μM. 2) Tien and Kirk medium (TaK): glucose 40 g l -1 ; peptone 2 g l -1 ; yeast extract 2 g l -1 ; CaCl 2 2H 2 O 0.4 g l -1 ; KH 2 PO 4 2 g l -1 ; MgSO 4 .7H 2 O, 0.3 g l -1 . Pakistan Journal of Phytopathology, Published by: Pakistan Phytopathological Society www.pakps.com www.pjp.pakps.com info@pakps.com