Levansucrase gene from Zymomonas mobilis was expressed efficiently in Escherichia coil and the overproduced recombinant levansucrase amounted to 40% of the total cell protein. Using E. coil lysate, levan was synthesized in a sucrose-based medium enzymatically with the conversion yields of up to 46% from fructose liberated in 25 hrs of incubation. More levan was formed at lower temperatures in the reaction mixture, whereas higher temperatures were favoured for the accumulation of free fructose or short chain oligosaccharides.