Production and properties of the highly efficient raw starch digesting α-amylase from a Bacillus licheniformis ATCC 9945a

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• 作者：Nataš ; a Bož ; ić ; Jordi Ruiz ; Josep Ló ; pez-Santí ; n ; Zoran Vuj&#x10d ; ić
• 关键词：α ; -Amylase ; Bacillus licheniformis ; Raw starch hydrolysis ; Thermostable ; Purification
• 刊名：Biochemical Engineering Journal
• 出版年：2011
• 出版时间：15 January 2011
• 年：2011
• 卷：53
• 期：2
• 页码：203-209
• 全文大小：774 K

文摘

Highly efficient raw starch digesting α-amylase was produced after 24 h of batch fermentation of Bacillus licheniformis ATCC 9945a in laboratory bioreactor at 37 °C. The enzyme was purified by gel filtration chromatographies with 6-fold increase of specific activity and 38 % recovery and showed a molecular mass of 31 kDa by SDS-PAGE. The purified enzyme had an optimum pH of 6.5 and optimum temperature of 90 °C. The purified α-amylase in the presence of CaCl₂ retained 55 % of its activity after 6 h of incubation at 70 °C. Co²⁺, Ni²⁺ and Ca²⁺ slightly stimulated, while Hg²⁺ completely inhibited α-amylase activity. Hydrolysis rates of raw triticale, wheat, potato, horseradish and corn starches, at 1 % concentration were 63, 60, 59, 52 and 37 % , respectively, in a period of 4 h. The properties of the purified enzyme proved its high efficacy for digesting diverse raw starches below gelatinization temperature and, hence, its potential commercial value to use as an industrial enzyme.