摘要
为开发耐高温、热稳定性高的β-甘露聚糖酶,以魔芋胶为唯一碳源,采用透明圈法,从土壤中筛选产β-甘露聚糖酶的菌株;通过16S rDNA序列及分子发育树分析对菌株进行鉴定;采用DNS法测定β-甘露聚糖酶活性并对酶学性质进行研究。结果表明,该菌能够水解魔芋胶,水解圈D/d比值平均为1.67;鉴定该菌为地衣芽孢杆菌(Bacillus licheniformis)KD-1;该菌所产β-甘露聚糖酶最适pH6.0,最适反应温度60℃;在pH5.0~9.0和60~80℃,酶的稳定性良好,60、70和80℃酶的半衰期(T1/2)分别为5.5、4.3和4.2 h;10 mmol/L的Cu^(2+)和Mg^(2+)明显促进β-甘露聚糖酶活性,而Mn^(2+)明显抑制酶活性。本研究筛选到一株地衣芽孢杆菌KD-1,其所产β-甘露聚糖酶,高温下(如80℃)热稳定性高于目前报道的β-甘露聚糖酶。
To develop a thermostableβ-mannanase,a highβ-mannanase producing strain was isolated from soil based on the sole carbon source cultivation and clearing zone screening on konjac powder plates.The strain was identified by 16S rDNA phylogenetic analysis.Theβ-mannanase activity and the enzyme properties were assayed by DNS method.The results showed that the strain could hydrolyze konjac powder and the clearing zone D/d value was about 1.67.The strain was assigned to Bacillus licheniformis KD-1.The optimal pH of the enzyme was pH6.0 and the optimal temperature was 60℃.Theβ-mannanase was stable at pH5.0~9.0 and 60~80℃.The half-life time(T1/2)of the enzyme activity was 5.5,4.3 and 4.2 h at 60,70 and 80℃.Theβ-mannanase activity was promoted by 10 mmol/L Cu2+and Mg2+,whereas the enzyme activity was inhibited by 10 mmol/L Mn2+.In this study,a strain of Bacillus licheniformis KD-1 was screened.The thermostability ofβ-mannanase produced by KD-1 was higher than that ofβ-mannanase reported at present.
作者
田庚
高伟强
陈晓波
张春晓
TIAN Geng;GAO Wei-qiang;CHEN Xiao-bo;ZHANG Chun-xiao(College of Bioscience and Bioengineering,Hebei University of Science and Technology,Shijiazhuang 050018,China)
出处
《食品工业科技》
CAS
北大核心
2020年第19期127-131,共5页
Science and Technology of Food Industry
基金
河北省重点研发项目(19222906D)
河北科技大学校立基金项目(2015PT45)。
