Screening, production, and characterization of dextranase from Catenovulum sp.

A psychrotolerant dextranase-producing bacterium was isolated from the Gaogong island seacoast near Jiangsu, China. The bacterium, denoted as DP03, was identified as Catenovulum sp. based on its phenotype, biochemical characteristics, and 16S rRNA gene comparison. The optimal enzyme production time, initial pH, temperature, and aeration conditions of strain DP03 were found to be 28 h, 8.0, 30 °C, and 25 % volume of liquid in 100-ml Erlenmeyer flasks, respectively. The ability of 1 % dextran T20 to induce dextranase was investigated. Dextranase from strain DP03 displayed its maximum activity at pH 8.0 and 40 °C and was found to be stable at 30 °C and over a broad range of pH values (pH 6–11). Scanning electron microscopy showed that dextranase from the isolate DP03 could at least partially prevent Streptococcus mutans from forming biofilms on glass coverslips.