Abstract
UDP-glucose (UDP-G), the direct precursor of cellulose, is known to be produced from UTP and glucose-1-phosphate. In an attempt to increase UTP biosynthesis, 5-fluorouridine (5-FUR: a pyrimidine analog)-resistant mutants were obtained using Acetobacter xylinum subsp. nonacetoxidans 757 as the parent strain. One of the 5-FUR-resistant mutants, FUR-35, showed about 40% higher cellulose productivion compared to the parent strain. Intracellular levels of UTP and UDP-G in FUR-35 was found to be higher than those in the parent strain. The carbamyl phosphate synthetase II (CPS) activity of FUR-35 was higher than that of the parent strain and the feedback inhibition of CPS by UTP in FUR-35 had been released compared with that in the parent strain. These results suggest that the increased cellulose production of FUR-35 was attributable to its higher of intracellular UDP-G level resulting from increased UTP biosynthesis.
