Extracellular Hydrolysis of Starch in Sugarcane Cell Suspensions

Evidence is presented for the increased excretion of amylolytic enzymes into a sugarcane cell culture medium when starch was substituted for sucrose as an energy source. The excretion was further enhanced by the inclusion of 1 mum gibberellic acid in the nutrient medium. The growth rate of the cells increased after they became adapted to starch relative to cells grown on sucrose, but the rate of amylolytic enzyme excretion remained unaltered. Amylolytic enzymes in the medium included alpha-amylase but the identity of one or more other enzymes related to starch hydrolysis remains in doubt.