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 chromatography. The optimum pH for levan production was pH 5 and the optimum temperature was 0°C. The higher velocity of levan formation within shorter enzyme reaction times was achieved by increasing the levels of enzyme concentration. The optimal sucrose concentration for levan production was around 20%. Under these conditions, more than 50 g levan/l was produced.ope