The
dextranase added in current commercial
dextranase-containing
mouthwashes is largely from fungi. However, fungal
dextranase has shown much higher optimum temperature than bacterial
dextranase and relatively low activity when used in human oral cavities. Bacterial
dextranase has been considered to be more effective and suitable for
dental caries prevention. In this study, a
dextranase (Dex410) from marine Arthrobacter sp. was purified and characterized. Dex410 is a 64-kDa
endoglycosidase. The specific activity of Dex410 was 11.9 U/mg at optimum pH 5.5 and 45 °C. The main end-product of Dex410 was
isomaltotriose, isomaltoteraose, and
isomaltopentaose by hydrolyzing
dextran T2000. In vitro studies showed that Dex410 effectively inhibited the Streptococcus mutans biofilm growth in coverage, biomass, and water-soluble
glucan (WSG) by more than 80, 90, and 95 %, respectively. The animal experiment revealed that for short-term use (1.5 months), both Dex410 and the commercial mouthwash
Biotene (Laclede Professional Products, Gardena, CA, USA) had a significant inhibitory effect on caries (p = 0.0008 and 0.0001, respectively), while for long-term use (3 months), only Dex410 showed significant inhibitory effect on
dental caries (p = 0.005). The
dextranase Dex410 from a marine-derived Arthrobacter sp. strain possessed the
enzyme properties suitable to human oral environment and applicable to
oral hygiene products.