Purification and partial characterization of a novel glucanhydrolase from Lipomyces starkeyi KSM 22 and its use for inhibition of insoluble glucan formation

A novel glucanhydrolase from a mutant of Lipomyces starkeyi ATCC 74054 was purified. The single protein (100 kDa) showed either dextranolytic or amylo lytic activity. We referred to the glucanhydrolase as a DXAMase. The DXAMas e was produced in a starch medium and it was 3.75-fold more active for hydr olysis of the purified insoluble-glucan of Streptococcus mutans than Penici llium funiculosum dextranase. Aggregation of S. mutans cells with dextran a nd adherence to glass were eliminated by incubating with the DXAMase. The a ddition of DXAMase (0.1 IU/ml) to the mutansucrase reaction digest with suc rose reduced the formation of insoluble-glucan about 80%. Also the DXAMase (0.5 IU/ml) removed 80% of the pre-formed sucrose-dependent adherent film. These in vitro properties of L. starkeyi KSM 22 DXAMase are desirable for i ts application as a dental plaque control agent.