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Kinetic modeling of a bi‐enzymatic system for efficient conversion of lactose to lactobionic acid
Author(s) -
Van Hecke Wouter,
Bhagwat Aditya,
Ludwig Roland,
Dewulf Jo,
Haltrich Dietmar,
Van Langenhove Herman
Publication year - 2008
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.22165
Subject(s) - chemistry , laccase , cellobiose dehydrogenase , cellobiose , redox , glucose oxidase , electron transfer , electron acceptor , ferricyanide , combinatorial chemistry , enzyme , inorganic chemistry , organic chemistry , cellulase
A model has been developed to describe the interaction between two enzymes and an intermediary redox mediator. In this bi‐enzymatic process, the enzyme cellobiose dehydrogenase oxidizes lactose at the C‐1 position of the reducing sugar moiety to lactobionolactone, which spontaneously hydrolyzes to lactobionic acid. 2,2′‐Azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt is used as electron acceptor and is continuously regenerated by laccase. Oxygen is the terminal electron acceptor and is fully reduced to water by laccase, a copper‐containing oxidase. Oxygen is added to the system by means of bubble‐free oxygenation. Using the model, the productivity of the process is investigated by simultaneous solution of the rate equations for varying enzyme quantities and redox mediator concentrations, solved with the aid of a numerical solution. The isocharts developed in this work provide an easy‐to‐use graphical tool to determine optimal process conditions. The model allows the optimization of the employed activities of the two enzymes and the redox mediator concentration for a given overall oxygen mass transfer coefficient by using the isocharts. Model predictions are well in agreement with the experimental data. Biotechnol. Bioeng. 2009;102: 1475–1482. © 2008 Wiley Periodicals, Inc.