Expression and characterization in E. coli of a neutral invertase from a metagenomic library

A gene encoding Uninv, an invertase active in the neutral pH range, was isolated from a metagenomic library and the enzyme was biochemically characterized. The enzyme had an optimum pH of 6.5 and an optimum temperature of 50A degrees C. It showed maximal similar to 37% sequence identity to all invertases identified so far. Uninv displayed typical Michaelis-Menten kinetics with substrate inhibition of sucrose, but it retained 50% activity at sucrose concentrations up to 1,000 mM. Uninv had no transfructosylating activity even at high sucrose concentrations. These properties will make this enzyme useful in the food industry.