OPTIMAL CONDITIONS FOR LEVAN FORMATION BY AN OVEREXPRESSED RECOMBINANT LEVANSUCRASE

A genetically modified levansucrase, which contained His-affinity tag in its C-terminal, was constructed by PCR reaction using two synthetic primers. This modified protein was produced up to 30 % in total cell protein of E. coli, and was purified by a one-step affinity chromatogr aphy. The optimum pH for levan production was pH 5 and the optimum tem perature was 0 degrees C. The higher velocity of levan formation withi n shorter enzyme reaction times was achieved by increasing the levels of enzyme concentration. The optimal sucrose concentration for levan p roduction was around 20 %. Under these conditions, more than 50 g leva n/l was produced.