Production of the Enzyme Cyclodextrin Glycosyltransferase Using Different Fermentation Techniques

Abstract

Cyclodextrins produced by cyclodextrin glycosyltransferase (CGTase) are widely used in the pharmaceutical industry to improve the solubility of drug substances as well as protect them against oxidation. The use of this enzyme in the cosmetics industry is also significant. CGTase is an enzyme that belongs to the α-amylase family, which is part of the group of non-Leloir glycosyltransferases. Enzyme-catalysed transglycosylation reactions may involve cyclization, coupling and disproportionation processes. The enzyme CGTase is mostly used to produce cyclodextrins (CDs). CGTase can produce α-, β- and γ-CDs during transglycosylation reactions, depending on the number of glucopyranose units involved (6, 7 or 8). The enzyme CGTase can also be used for enzymatic bioconversion, e.g., in the development of alternative sweeteners, where the bitter aftertaste of the product is reduced during the enzymatic bioconversion of steviol glycosides, thereby obtaining an even sweeter and more advantageous material. In our research, the enzyme CGTase was produced using different fermentation techniques to compare the activity and amount of CGTase produced by each process and optimize the subsequently planned scale-up. In our studies, the strain DSM 13 of Bacillus licheniformis was used, which produced CGTase extracellularly. During the experiments the batch, fed-batch and semi-continuous fermentation techniques were compared in terms of enzymatic production. All cultivation processes were carried out in a desktop lab scale fermenter.