Abstract
Chitosanase plays an important role in the production of chitooligosaccharides (CHOS), which possess various biological activities. Herein, a glycoside hydrolase (GH) family 46 chitosanase-encoding gene, csnB, was cloned from marine bacterium Bacillus sp. BY01 and heterologously expressed in Escherichia coli. The recombinant chitosanase, CsnB, was optimally active at 35 °C and pH 5.0. It was also revealed to be a cold-adapted enzyme, maintaining 39.5% and 40.4% of its maximum activity at 0 and 10 °C, respectively. Meanwhile, CsnB showed wide pH-stability within the range of pH 3.0 to 7.0. Then, an improved reaction condition was built to enhance its thermostability with a final glycerol volume concentration of 20%. Moreover, CsnB was determined to be an endo-type chitosanase, yielding chitosan disaccharides and trisaccharides as the main products. Overall, CsnB provides a new choice for enzymatic CHOS production.
Highlights
Chitin, the second most important natural polymer compound after cellulose on earth [1], is an insoluble liner polymer of β-1,4-linked N-acetyl-d-glucosamine [2,3]
The reported cold-adapted chitosanases are often unstable [19] when the reaction temperature slightly increases, which limits its application in industrial production
A sea mud sample from Yellow Sea sediment was spread on selection plates containing chitosan (0.50%) and a chitosanase-producing bacterial strain was isolated
Summary
The second most important natural polymer compound after cellulose on earth [1], is an insoluble liner polymer of β-1,4-linked N-acetyl-d-glucosamine [2,3]. CHOS has been shown to have potential medical functions [6,7], including but not limited to anti-bacterial effect [8], anti-oxidant effect [9], anti-obesity effect [10], hypoglycemic effect [9,11], and anti-tumor effect [7] These excellent properties are why CHOS is widely used in agriculture, cosmetics, food, medicine, and other fields [6,12,13]. The reported cold-adapted chitosanases are often unstable [19] when the reaction temperature slightly increases (more than 30 ◦ C), which limits its application in industrial production. In order to overcome the deficiencies in the industrial production process of cold-adapted enzymes, we improved the reaction conditions by means of adding glycerol and exploring its appropriate concentration. It was found that CsnB is an endo-type chitonase, resulting in disaccharide and trisaccharide degradation products
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
