A large-scale production system of uridine 5'-diphospho-galactose (UDP-Gal) has been established by the combination of recombinant Escherichia coli and Corynebacterium ammoniagenes. Recombinant E. coli that overexpress the UDP-Gal biosynthetic genes galT, galK, and galU were generated. C. ammoniagenes contribute the production of uridine triphosphate (UTP), a substrate for UDP-Gal biosynthesis, from orotic acid, an inexpensive precursor of UTP. UDP-Gal accumulated to 72 mM (44 g/L) after a 21 h reaction starting with orotic acid and galactose. When E. coli cells that expressed the alpha1,4-galactosyltransferase gene of Neisseria gonorrhoeae were coupled with this UDP-Gal production system, 372 mM (188 g/L) globotriose (Galalpha1-4Galbeta1-4Glc), a trisaccharide portion of verotoxin receptor, was produced after a 36 h reaction starting with orotic acid, galactose, and lactose. No oligosaccharide by-products were observed in the reaction mixture. The production of globotriose was several times higher than that of UDP-Gal. The strategy of producing sugar nucleotides by combining metabolically engineered recombinant E. coli with a nucleoside 5'-triphosphate producing microorganism, and the concept of producing oligosaccharides by coupling sugar nucleotide production systems with glycosyltransferases, can be applied to the manufacture of other sugar nucleotides and oligosaccharides.

Large-scale production of UDP-galactose and globotriose by coupling metabolically engineered bacteria.

Recent developments in sample preparation for chromatographic analysis of carbohydrates.

Simulated Moving Bed or SMB chromatography is a continuous adsorption technique that increases throughput, purity and yield relative to batch chromatography. SMB utilizes a series of columns with periodically moving inlet and outlet ports. This technique has been applied for the production of petrochemicals and sugars, and to a limited extent, pharmaceuticals. The recent surge in SMB research has led to various novel SMB schemes or configurations. This review presents a survey and comparison of SMB schemes and equipment, specifically SMB valve designs, which are needed to implement the various schemes. Illustrated examples include SMBs with three, four, five, eight, nine, or twelve zones, Varicol scheme, Japan Organo process, fast startup and shutdown, and online decoupled regeneration. The SMB valve designs reviewed are classified into central and distributed valves designs, which include two‐way‐valve designs and rotary‐valve designs. We also present a novel SMB design, the Versatile SMB or V‐S...

P. Phemius

Papers

Continuous chromatographic separation process : simulated moving bed allowing simultaneous withdrawal of three fractions

Chromatographic separation of polyols by ligand exchange: Effects of the ion-exchange resin cross-linking and size