A simple and efficient method for the purification of membrane-bound levansucrase from Zymomonas mobilis

A new and efficient method for the purification of levansucrase from cell-free extracts of a flocculant mutant of Zymomonas mobilis ATCC 10988 was developed. Levansucrase activity was almost completely recovered and purified by a factor of 15 after precipitation with 0.1 m MnCl2 as a first capturing step. The enzyme was homogeneously purified by ultrafiltration and anion-exchange chromatography and exhibited a levan-forming activity of 39.2 U mg-1. The native enzyme formed large aggregates with an apparent molecular mass of more than 106 Da as determined by size-exclusion chromatography, whereas denaturing SDS-PAGE indicated an apparent molecular mass of 50 kDa for the subunits.