BIOTECHNOLOGY LETTERS Volume 18 No.2 (February 1996)p.143-144 Received 29th November. GALACTOOLIGOSACCHARIDE SYNTHESIS FROM LACTOSE BY Penicillium funiculosum CELLULASE Hyun-Jae Shin and Ji-Won Yang* BioProcess Engineering Research Center, Department of Chemical Engineering, KAIST, 373-1, Kusung-dong, Yusung-gu, Taejon, 305-701, Korea INTRODUCTION Cellulase is an undefined extracellular enzyme mixture, produced by various fungi, bacteria, insects and other lower animals, that hydrolyses cellulose. Typical fungi secreting the cellulase are as follows: Triclu~dernu7reesei, T. viride, Aspergillus niger and Penicillium funiculosum (Farkas et al, 1982; Shikata and Nishizawa, 1975; Hurst et al., 1977; Wood et al., 1980). The cellulase produced by the fungi mainly consists of three types of enzymes: endoglucanase, exoglucanase, and l~-glucosidase. In addition to the hydrolytic activities, transglycosylation by cellulase is already well known. Recently, Shoda et al. (1993) reported a cellulase- catalyzed lactosylation of alkyl cellobioside giving rise to cellooligosaccharide derivatives in a mixed buffer/organic solvent system. Although translactosylation and transglucosylation among transglycosylation were reported many times, transgalactosylation to catalyze galactosyl glycoside synthesis such as galactooligosaccharide (GOS) has not been reported yet. GOS, that could be used as bifidus promoter and cosmetic additives, has been synthesized mostly by ~galactosidase (Mozaffar et al., 1987; Prenosil et al., 1987). In this note, we report that GOS can be synthesized efficiently from lactose by commercially available P. funiculosum cellulase. MATERIALS AND METHODS Materials: Penicilliumfuniculosum cellulase was obtained from Sigma (USA). Lactose and other carbohydrate standards were obtained from TCI (Japan) and Sigma. All other reagents were of analytical grade. Analytical Methods: All carbohydrates produced from enzymatic reactions were analyzed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) (Yang et al., 1994). Enzym e Assay: Carboxymethylcellulose hydrolase (CMCase) and lB-galactosidase activity were measured alter the method of Kim et al. (1994) and Nagano et al. (1992), respectively. Degree of transgalactosylation was estimated by TLC analysis using 1% (w/v) lactose as substrate after 1-day incubation at 40°C. RESULTS AND DISCUSSION A 2 mL enzyme solution (10 mg-protein/mL) in 50 mM acetate buffer (pH 5.0) was mixed with 38 mL of 5% (w/v) lactose solution in the buffer at 40°C. The reaction of the P..fimicMosum cellulase ~ith lactosc resulted in a number of GOS (mainly tri- and tetrasaccharide) in addition to the hydrolysis products, glucose and galactosc The concentration of galactose was always lower than that of glucose suggesting that the GOS produced was transgalactosylation product (FIG. 1). The maximum formation of 20% (w/w) GOS (sum of tri- and 143