2. Academic Validation
  3. Characterization of an Alkaline GH49 Dextranase from Marine Bacterium Arthrobacter oxydans KQ11 and Its Application in the Preparation of Isomalto-Oligosaccharide

Characterization of an Alkaline GH49 Dextranase from Marine Bacterium Arthrobacter oxydans KQ11 and Its Application in the Preparation of Isomalto-Oligosaccharide

  • Mar Drugs. 2019 Aug 19;17(8):479. doi: 10.3390/md17080479.
Hongfei Liu 1,  Wei Ren 1 2,  Mingsheng Ly 1 3,  Haifeng Li 4,  Shujun Wang 5 6
Affiliations

Affiliations

  • 1 Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang 222005, China.
  • 2 Collaborative Innovation Center of Modern Bio-Manufacture, Anhui University, Hefei 230039, China.
  • 3 Co-Innovation Center of Jiangsu Marine Bio-Industry Technology, Jiangsu Ocean University, Lianyungang 222005, China.
  • 4 Medical College, Hangzhou Normal University, Hangzhou 311121, China. lihf@hznu.edu.cn.
  • 5 Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang 222005, China. shujunwang86@163.com.
  • 6 Co-Innovation Center of Jiangsu Marine Bio-Industry Technology, Jiangsu Ocean University, Lianyungang 222005, China. shujunwang86@163.com.
PMID: 31430863 DOI: 10.3390/md17080479
Abstract

A GH49 dextranase gene DexKQ was cloned from marine bacteria Arthrobacter oxydans KQ11. It was recombinantly expressed using an Escherichia coli system. Recombinant DexKQ dextranase of 66 kDa exhibited the highest catalytic activity at pH 9.0 and 55 °C. kcat/Km of recombinant DexKQ at the optimum condition reached 3.03 s-1 μM-1, which was six times that of commercial dextranase (0.5 s-1 μM-1). DexKQ possessed a Km value of 67.99 µM against dextran T70 substrate with 70 kDa molecular weight. Thin-layer chromatography (TLC) analysis showed that main hydrolysis end products were isomalto-oligosaccharide (IMO) including isomaltotetraose, isomaltopantose, and isomaltohexaose. When compared with glucose, IMO could significantly improve growth of Bifidobacterium longum and Lactobacillus rhamnosus and inhibit growth of Escherichia coli and Staphylococcus aureus. This is the first report of dextranase from marine bacteria concerning recombinant expression and application in isomalto-oligosaccharide preparation.

Keywords

dextranase; expression; isomalto-oligosaccharide (IMO); marine bacteria.

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