The living factory: In vivo production of N-acetyllactosamine containing carbohydrates in E-coli

Scientific and commercial interest in oligosaccharides is increasing, but t heir availability is limited as production relies on chemical or chemo-enzy matic synthesis. In search for a more economical, alternative procedure, we have investigated the possibility of producing specific oligosaccharides i n E. coli that express the appropriate glycosyltransferases. The Azorhizobi um chitin pentaose synthase NodC (a beta(1,4)GlcNAc-transferase), and the N eisseria beta(1,4)galactosyltransferase LgtB, were co-expressed in E. coli. The major oligosaccharide isolated from the recombinant strain, was subjec ted to LC-MS, FAB-MS and NMR analysis, and identified as beta Gal(1,4)[beta GlcNAc(1,4)](4)GlcNAc. High cell density culture yielded more than 1.0 gr of the hexasaccharide per liter of culture. The compound was found to be an acceptor in vitro for beta Gal(1,4)GlcNAc alpha(1,3)galactosyltransferase, which suggests that the expression of additional glycosyltransferases in E . coli will allow the production of more complex oligosaccharides.