Recombinant mannitol dehydrogenase from Pseudomonas fluorescens for the production of the sugar substitute mannitol.
Abstract
In this research project an enzyme technological process for the production of mannitol is investigated. This sugar alcohol has important applications in both food technology and medicine. The central biocatalyst for this novel process is mannitol dehydrogenase (MDH) from Pseudomonas fluorescens which can be conveniently overexpressed in two recombinant E. coli strains. Thus the enzyme is available in sufficient quantities to scale up such an enzymatic production process. In the first phase of this project the production of recombinant MDH is optimized by selecting a suitable culture medium, an appropriate mode of cultivation (fed-batch strategy) as well as a suitable induction protocol. In a second part of this project MDH-catalyzed formation of mannitol from fructose is investigated. Since MDH is dependent on the coenzyme NAD which is consumed in stoichiometric amounts during this reaction, NAD has to be regenerated continuously for an efficient, economical use in an enzymatic process. This regeneration is most conveniently performed by a second enzymatic reaction. This complex system (2 enzymes, 2 substrates, coenzyme, buffer, etc.) is characterized and optimized.
Project staff
Dietmar Haltrich
Univ.Prof. Dipl.-Ing.Dr.techn. Dietmar Haltrich
dietmar.haltrich@boku.ac.at
Tel: +43 1 47654-75211
Project Leader
01.08.1997 - 31.07.1999