GALACTO-OLIGOSACCHARIDE PRODUCTION FROM LACTOSE BY SIROBASIDIUM-MAGNUM CBS6803

Galacto-oligosaccharide (Gal-OS) was produced from lactose by a yeast, Sirobasidium magnnm CBS6803. With toluene-treated resting cells, 136 mg ml(-1) of Gal-OS was produced from 360 mg ml(-1) of lactose at 50 d egrees C for 42 h. Then, the yield of Gal-OS was increased by a cultur e method in which cell growth followed the enzymatic reaction: 224 mg ml(-1) of Gal-OS was produced at 30 degrees C for 60 h. Finally, combi nation of the toluene-treated resting cells and glucose oxidase plus c atalase was applied to improve productivity by the removal of a by-pro duct, glucose, which inhibits the Gal-OS production, from the reaction mixture. In this case, 242 mg ml(-1) of Gal-OS was produced at 50 deg rees C for 42 h without cell growth. The structure of the major produc t was identified as 4'-galactosyl-lactose.