Real-time monitoring of enzymatic hydrolysis of 1,3(4)-β-glucan with high-resolution ultrasonic spectroscopy

Abstract

The paper describes the application of High-Resolution Ultrasonic Spectroscopy for real-time, non-destructive, precision monitoring of enzymatic hydrolysis of polysaccharides in aqueous solutions, represented by barley 1,3(4)-β-D-glucan. The technique provided time profiles of the concentration of glycosidic bonds hydrolyzed, degree of hydrolysis, average degree of polymerization, and molar mass of hydrolysates produced. The limiting precision of the technique in measurements of the concentration of glycosidic bonds hydrolyzed is at the level of 0.01 mmol kg−1. The Michaelis constant Km for the enzyme employed, endo-1,3(4)-β-d-glucanase from Talaromyces emersonii, calculated from the ultrasonic reaction profiles was 0.061 mol L−1 at 50 °C, in 0.1 mol L−1 NaOAc buffer, pH 5.0 at 50 °C. The Mark-Houwink parameter a of the polysaccharide hydrolysates, obtained from correlation of ultrasonically measured evolution of average molar mass and of viscosity, was 0.63.