The transport and mediation mechanisms of the common sugars in Escherichia coli.

Escherichia coli can uptake and utilize many common natural sugars to form biomass or valuable target bio-products. Carbon catabolite repression (CCR) will occur and hamper the efficient production of bio-products if E. coli strains are cultivated in a mixture of sugars containing some preferred sugar, such as glucose. Understanding the transport and metabolism mechanisms of the common and inexpensive sugars in E. coli is important for further improving the efficiency of sugar bioconversion and for reducing industrial fermentation costs using the methods of metabolic engineering, synthetic biology and systems biology. In this review, the transport and mediation mechanisms of glucose, fructose, sucrose, xylose and arabinose are discussed and summarized, and the hierarchical utilization principles of these sugars are elucidated.