Mass transfer control of enzymatic hydrolysis of polysaccharides by glucoamylase

Abstract

6 pages, 6 figures, 2 tablesA kinetic study of the enzymatic hydrolysis of starch, amylopectin, and glycogen solutions at several concentrations by a commercial glucoamylase was carried out. The results show a decreasing reaction rate zone when starch and amylopectin are used as substrates, at concentrations higher than 50 and 10 g l−1, respectively. In spite of that, the experimental data can be well fitted to a substrate inhibition model. Additional experiments [(i) working at lower substrate concentrations but keeping the same substrate/enzyme ratio; (ii) in static or shaken conditions; (iii) with/without addition of a thickener agent] led us to conclude that hydrolysis of high viscosity starch and amylopectin solutions is controlled by the mass transfer rate.We acknowledge CAICYT and CICYT for their economic support (Projects 1D87060 and BIO89-0264)Peer reviewe