CARBOHYDRATE-METABOLISM IN ZYMOMONAS-MOBILIS - A CATABOLIC HIGHWAY WITH SOME SCENIC ROUTES

Sucrose, glucose and fructose are degraded in the Gram-negative bacter ium Zymomonas mobilis via an anaerobic version of the Entner-Doudoroff pathway, to an equimolar mixture of ethanol and carbon dioxide. Sucro se is split extracellularly into glucose and fructose (or levan). The two sugars are transported into the cell via facilitated diffusion (un iport). A periplasmic enzyme, glucose-fructose oxidoreductase, provide s the novel compatible solute, sorbitol, to counteract detrimental osm otic stress. Carbon flux and its regulation, and branches into anaboli c pathways are discussed together with recent approaches to broaden th e substrate range of the bacterium.