Purification and functional characterization of endo-¦Â-mannanase MAN5 and its application in oligosaccharide production from konjac flour

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• 作者：Min Zhang ; Xiu-Lan Chen ; Zhi-Hua Zhang ; Cai-Yun Sun ; Lei-Lei Chen ; Hai-Lun He ; Bai-Cheng Zhou and Yu-Zhong Zhang
• 关键词：Endo ; beta ; mannanase ; MAN5 ; Oligosaccharides preparation ; Konjac flour ; Bacillus sp. MSJ ; 5
• 刊名：Applied Microbiology and Biotechnology
• 出版年：2009
• 出版时间：July, 2009
• 年：2009
• 卷：83
• 期：5
• 页码：865-873
• 全文大小：266.6 KB

文摘

MAN5, the main extracellular saccharide hydrolase from Bacillus sp. MSJ-5, is an endo-β-mannanase with a demand of at least five sugar moieties for effective cleavage. It has a pH optimum of 5.5 and a temperature optimum of 50¡ãC and is stable at pH 5–9 or below 65¡ãC. MAN5 has a very high ability to hydrolyze konjac flour, 10 U/mg of which could completely liquefy konjac flour gum in 10 min at 50¡ãC. HPLC analysis showed that most glucomannan in the konjac flour was hydrolyzed into a large amount of oligosaccharides with DP of 2–6 and a very small amount of monosaccharide. With the culture supernatant as enzyme source, the optimum condition to prepare oligosaccharides from konjac flour was obtained as 10 mg/ml konjac flour incubated with 10 U/mg enzyme at 50¡ãC for 24 h. With this condition, more than 90 % polysaccharides in the konjac flour solution were hydrolyzed into oligosaccharides and a little monosaccharide (2.98 % of the oligosaccharides). Konjac flour is an underutilized agricultural material with low commercial value in China. With MAN5, konjac flour can be utilized to generate high value-added oligosaccharides. The high effectiveness and cheapness of this technique indicates its potential in industry.