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Dental plaque is a high-incidence health concern, and it is caused by Streptococcus mutans. Dextranase can specifically hydrolyze ɑ-1,6-glycosidic linkages in dextran. It is commonly used in the sugar industry, in the production of plasma substitutes, and the treatment and prevention of dental plaque. In this research work, we successfully cloned and expressed a cold-adapted dextranase from marine bacteria Catenovulum sp. DP03 in Escherichia coli. The recombinant dextranase named Cadex2870 contained a 2511 bp intact open reading frame and encoded 836 amino acids. The expression condition of recombinant strain was 0.1 mM isopropylthio-galactoside (IPTG), and the reduced temperature was 16 °C. The purified enzyme activity was 16.2 U/mg. The optimal temperature and pH of Cadex2870 were 45 °C and pH 8, and it also had catalytic activity at 0 °C. The hydrolysates of Cadex2870 hydrolysis Dextran T70 are maltose, maltotetraose, maltopentose, maltoheptaose and higher molecular weight maltooligosaccharides. Interestingly, 0.5% sodium benzoate, 2% xylitol, 0.5% sodium fluoride, 5% propanediol, 5% glycerin and 2% sorbitol can enhance stability Cadex2870, which are additives in mouthwashes. Additionally, Cadex2870 reduced the formation of dental plaque and effectively degraded formed plaque. Therefore, Cadex2870 shows great promise in commercial applications., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Dextranase, a hydrolase that specifically hydrolyzes α-1,6-glucosidic bonds, has been used in the pharmaceutical, food, and biotechnology industries. In this study, the strain of Catenovulum agarivorans MNH15 was screened from marine samples. When the temperature, initial pH, NaCl concentration, and inducer concentration were 30 °C, 8.0, 5 g/L, and 8 g/L, respectively, it yielded more dextranase. The molecular weight of the dextranase was approximately 110 kDa. The maximum enzyme activity was achieved at 40 °C and a pH of 8.0. The enzyme was stable at 30 °C and a pH of 5-9. The metal ion Sr 2+ enhanced its activity, whereas NH 4+ , Co 2+ , Cu 2+ , and Li + had the opposite effect. The dextranase effectively inhibited the formation of biofilm by Streptococcus mutans . Moreover, sodium fluoride, xylitol, and sodium benzoate, all used in dental care products, had no significant effect on dextranase activity. In addition, high-performance liquid chromatography (HPLC) showed that dextran was mainly hydrolyzed to glucose, maltose, and maltoheptaose. The results indicated that dextranase has high application potential in dental products such as toothpaste and mouthwash., Competing Interests: The authors confirm that there is no conflict of interests regarding this paper.

The enzyme dextranase is widely used in the sugar and food industries, as well as in the medical field. Most land‐derived dextranases are produced by fungi and have the disadvantages of long production cycles, low tolerance to environmental conditions, and low safety. The use of marine bacteria to produce dextranases may overcome these problems. In this study, a dextranase‐producing bacterium was isolated from the Rizhao seacoast of Shandong, China. The bacterium, denoted as PX02, was identified as Cellulosimicrobium sp. and its growing conditions and the production and properties of its dextranase were investigated. The dextranase had a molecular weight of approximately 40 kDa, maximum activity at 40°C and pH 7.5, with a stability range of up to 45°C and pH 7.0–9.0. High‐performance liquid chromatography showed that the dextranase hydrolyzed dextranT20 to isomaltotriose, maltopentaose, and isomaltooligosaccharides. Hydrolysis by dextranase produced excellent antioxidant effects, suggesting its potential use in the health food industry. Investigation of the action of the dextranase on Streptococcus mutans biofilm and scanning electron microscopy showed that it to be effective both for removing and inhibiting the formation of biofilms, suggesting its potential application in the dental industry. [ABSTRACT FROM AUTHOR]

Dextranase specifically hydrolyzes dextran and is used to produce functional isomalto-saccharide prebiotics. Moreover, dextranase is used as an additive in mouthwash to remove dental plaque. We cloned and expressed the dextranase gene of the marine bacterium Bacillus aquimaris S5. The length of the BaDex gene was 1788 bp, encoding 573 amino acids. Using bioinformatics to predict and analyze the amino acid sequence of BaDex, we found the isoelectric point and instability coefficient to be 4.55 and 29.22, respectively. The average hydrophilicity (GRAVY) was −0.662. The secondary structure of BaDex consisted of 145 alpha helices, accounting for 25.31% of the protein; 126 extended strands, accounting for 21.99%; and 282 random coils, accounting for 49.21%. The 3D structure of the BaDex protein was predicted and simulated using SWISS-MODEL, and BaDex was classified as a Glycoside Hydrolase Family 66 protein. The optimal temperature and pH for BaDex activity were 40°C and 6.0, respectively. The hydrolysates had excellent antioxidant activity, and 8 U/mL of BaDex could remove 80% of dental plaque in MBRC experiment. This recombinant protein thus has great promise for applications in the food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The immobilization technology provides a potential pathway for enzyme recycling. Here, we evaluated the potential of using dextranase immobilized onto hydroxyapatite nanoparticles as a promising inorganic material. The optimal immobilization temperature, reaction time, and pH were determined to be 25 °C, 120 min, and pH 5, respectively. Dextranase could be loaded at 359.7 U/g. The immobilized dextranase was characterized by field emission gun-scanning electron microscope (FEG-SEM), X-ray diffraction (XRD), and Fourier-transformed infrared spectroscopy (FT-IR). The hydrolysis capacity of the immobilized enzyme was maintained at 71% at the 30th time of use. According to the constant temperature acceleration experiment, it was estimated that the immobilized dextranase could be stored for 99 days at 20 °C, indicating that the immobilized enzyme had good storage properties. Sodium chloride and sodium acetic did not desorb the immobilized dextranase. In contrast, dextranase was desorbed by sodium fluoride and sodium citrate. The hydrolysates were 79% oligosaccharides. The immobilized dextranase could significantly and thoroughly remove the dental plaque biofilm. Thus, immobilized dextranase has broad potential application in diverse fields in the future. [ABSTRACT FROM AUTHOR]