Abstrakt

Production of levan using immobilized Bacillus licheniformis levansucrase

Imen Dahech, Rania Bredai, Karima Srih

Bacillus licheniformis levansucrase was immobilized on different carriers using different immobilization methods including physical adsorption, covalent binding, ionic binding and entrapment. The most efficient immobilization was achieved by chitosan (10%) using glutaraldehyde as a bifunctional agent. Thismethod gave an immobilization yield of 83%and a levansucrase activity recovery of 97%. The immobilized enzyme exhibited a shift in the optimal pHfrom5.5 to 7.0, but the optimal temperature of activity was not affected. The immobilized enzyme retained about 50%of its initial catalytic activity even after being used during 5 successive uses. The main product synthesized was levan which could be used for important applications.