Kinetic modeling of the hydrolysis of sucrose by invertase

Abstract

SummaryThe kinetics of the enzymatic hydrolysis of sucrose by invertase have been examined, with particular emphasis on high substrate concentration. Initial rates of reaction were determined by following the production of glucose directly as a function of time over a wide range of substrate concentrations (0.04M to 2.06M). The resulting data reveal a reaction rate that increases gradually until the sucrose concentration reaches about 0.2921.3, after which the reaction velocity decreases with increasing sucrose concentration. Previous workers (e.g., Xelson and Schubertl) have reported a peak reaction velocity as determined by indirect polarimetric measurements of glucose, a t a sucrose concentration of about 0.17M. These measurements, however, neglect the intermediate oligosaccharides formed by the transferase action of invertase,8-lo and assume equal amounts of glucose and fructose. According to Anderson et u1.,Io these oligosaccharides interfere by producing an erroneously low reaction rate. Experimental results of this work confirm Anderson's observations, and show a further reaction rate increase of nearly 20% between sucrose concentrations of 0.177M and 0.285M under the same conditions of temperature, pH, and enzyme concentration.Effects of substrate diffusion, solution viscosity, water concentration, and substrate inhibition were experimentally studied and the results incorporated into a kinetic model that has proven satisfactory in modeling the experimental results. This model takes into account inhibition by primary substrate, with concentration of the secondary substrate water, as a rate limiting factor at sucrose concentrations greater than 0.285M.The effects of mixing, in terms of volumetric power input, on the reaction rate have been tested. Approximately 40-fold increase in volumetric power input caused no increase in the reaction rate. These experiments have shown that bulk mass transfer is not a rate limiting factor under the experimental conditions.

Production of Fructose and Ethanol from Cane Molasses Using Saccharomyces cerevisiae ATCC 36858

“…The decrease in the sucrose hydrolysis rates, when its concentration was above 100 g/l using invertase, was also reported [35,36]. This reduction was found to be due to the inhibition by a high substrate concentration [35]. In the present study, the ethanol yield was between 71% and 77% of the theoretical value, respectively, in media with sugar concentrations of between 96.7 g/l and 273.8 g/l (Tab.…”

“…However, with a further increase in the sugar concentration, the rate decreased. The decrease in the sucrose hydrolysis rates, when its concentration was above 100 g/l using invertase, was also reported [35,36]. This reduction was found to be due to the inhibition by a high substrate concentration [35].…”

Modeling and Application of UF-Stirred Cell Reactors in Hydrolysis of Saccharides

“…Under certain operating conditions, in which the process is solely controlled by the osmotic pressure, the membrane hydraulic resistance, R m , is assumed to play a dominating role [10]. Hence,…”

Enzyme immobilized in a packed‐bed reactor: Kinetic parameters and mass transfer effects

“…However, for invertase, substrate inhibition is important at sucrose concentrations above 0.3M. 30 Thus for sucrose-invertase systems, the zero-order model should apply for 0.12M << c < 0.3M, where we have used the K , value of Kobayashi and Moo-Young28 to obtain the lower limit.…”