Development of a multiphase reaction system for integrated synthesis of isomaltose with a new glucosyltransferase variant

Abstract

A new genetically derived variant of the glucosyltransferase from Streptococcus oralis has been characterized physicochemically and kinetically. Compared with the industrially used glucosyltransferase from Leuconostoc mesenteroides, the enzyme variant GTF-R S628D possesses 25 times higher affinity for the specific glucosylation of glucose. For a concept of integrated reaction and product isolation, a fluidized bed reactor with in situ product removal was applied. The technical feasibility and the applicability of the kinetic models for reaction and adsorption could be demonstrated. The immobilized enzyme was stable (20% activity loss after 192 h) and product could be obtained with 90% purity. A bioprocess model was generated which allowed the integral assessment of the enzymatic synthesis and in situ product adsorption. The model is a powerful tool which assists with the localization of optimal process parameters. It was applied for the process evaluation of other glucosyltransferases and demonstrated key characteristics of each enzymatic system.

Synthesis of Isomaltooligosaccharides by Saccharomyces cerevisiae Cells Expressing Aspergillus niger α-Glucosidase

“…The development of new procedures for the production of IMOs of defined composition, specifically, panose and isomaltose, is a significant biotechnological goal because of present and potential applications of these compounds. 18,28,29 Our results provide a procedure for inexpensive, food-grade production of panose and isomaltose, using an engineered yeast strain that displays a cell wall-linked α-glucosidase. The production of panose or isomaltose can be modulated by the ratio of the acceptor sugars (maltose or glucose) present in the reaction.…”

“…Industrial production of IMOs is carried out by the combined action of hydrolytic and transferase enzymes on starch, which yields a complex mixture of α-glucosides. ,, Although in general terms, IMOs are considered to have prebiotic and other health promoting properties, ,, the heterogeneous and variable nature or commercial preparations makes it difficult to ascribe observed effects to specific compounds. The development of new procedures for the production of IMOs of defined composition, specifically, panose and isomaltose, is a significant biotechnological goal because of present and potential applications of these compounds. ,, Our results provide a procedure for inexpensive, food-grade production of panose and isomaltose, using an engineered yeast strain that displays a cell wall-linked α-glucosidase. The production of panose or isomaltose can be modulated by the ratio of the acceptor sugars (maltose or glucose) present in the reaction.…”