Immobilisation of levansucrase on calcium phosphate gel strongly increases its polymerase activity.

The catalytic properties of levansucrase bound to hydroxyapatite were studied as a possible model for enzyme behaviour when associated in vivo to matrices such as the cell wall of bacteria or tooth surfaces. The activity of the immobilised enzyme was mainly directed towards its polymerase activity. The yield of levan reached 85%. The kcat of the enzyme for sucrose transformation was increased and the Km for this substrate was unmodified. These properties allow the design of a system for the large-scale production of high-molecular-weight branched-chain levan in vitro in high yield.