Characterizations and Applications of Different Chitosanases
學生姓名:
陳楷雯
指導教授:
方翠筠
學期:
111上
摘 要:
Chitooligosaccharide (COS) has various biological activities, including anti-oxidant activity and antifungal properties. Enzymatic hydrolysis using chitosanase can retain all amino and hydroxyl groups of chitosan intact. A new chitosanase gene, csnQ, consisting of 287 amino acid residues was cloned from the marine Bacillus sp. Q1098 and expressed in Escherichia coli. CsnQ showed maximal activity at 60℃, pH5.31. Estimation of CsnQ pH-stability showed it could retain more than 50% of its activity from pH 3.60 to 9.80. Moreover, chitobiose, the reaction product of enzymatic hydrolysis using CsnQ, has better free radical scavenging ability by vitro and in vivo analyses. CsnQ has great potential on COS production. An antifungal protein that inhibiting the growth of F. solani was observed in Bacillus subtilis SH21. During purification and subsequent sequence database search indicated that this protein was a chitosanase, named SH21. Scanning and transmission electron microscopy show that SH21 can cause hyphal ablation, distortion, or abnormalities, and cell-wall depression to inhibit the growth of F. solani. Due to the its special properties, chitosanase can serve as an excellent candidate for industrial applications. Examples include the production of COS for anti-oxidant therapy, as an ingredient of antifungal cream, and selection marker of fungi.
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