The microbial production systems

The microbial production system currently uses Escherichia coli as the host to express recombinant GT enzymes and synthesize glycoside products.  The advantage of the microbial production system is that the host cells provide the sugar nucleotides for the transfer reactions, by-passing the need and expense of providing supplementary co-factors.  This whole-cell biocatalysis system has been engineered and optimised for transfer reactions involving different sugar nucleotides.  Acceptors incubated with bacterial cultures are typically transported into the cells and the glycosides of those acceptors, produced by the GTs expressed in the bacterial cells, are exported out into the culture medium.  This process enables ease of purification of the products from the culture medium by chromatography. 

Microbial systems have been optimised for the production of glucosides, rhamnosides and glucuronides of natural and non-natural scaffolds; the architecture of these systems is shown below:

Computerised fermentation systems using a fed-batch strategy have been optimised allowing high cell density and efficient production.  Typical yields of the Glytech system range from 100 mg to 1 g of glycoside per litre of bacterial culture using a 3-litre fermentation vessel.  Scale-up of the fermentation process in 21 litre and 70 litre systems is in development.