生物技术通报 ›› 2021, Vol. 37 ›› Issue (10): 100-109.doi: 10.13560/j.cnki.biotech.bull.1985.2021-0106

• 研究报告 • 上一篇    下一篇

地衣芽孢杆菌KD-1β-甘露聚糖酶定点突变提高酶活性及稳定性

田庚(), 高伟强, 陈晓波, 张春晓()   

  1. 河北科技大学生物科学与工程学院,石家庄 050018
  • 收稿日期:2021-01-27 出版日期:2021-10-26 发布日期:2021-11-12
  • 作者简介:田庚,女,硕士研究生,研究方向:微生物技术;E-mail: 741033155@qq.com;
  • 基金资助:
    河北省重点研发计划项目(19222906D);河北省研究生创新资助项目(CXZZSS2020090)

Directed Mutagenesis of β-mannanase Gene from Bacillus licheniformis KD-1 for Improving Enzyme Activity and Stability

TIAN Geng(), GAO Wei-qiang, CHEN Xiao-bo, ZHANG Chun-xiao()   

  1. Department of Bioscience and Bioengineering,Hebei University of Science and Technology,Shijiazhuang 050018
  • Received:2021-01-27 Published:2021-10-26 Online:2021-11-12

摘要:

对地衣芽孢杆菌β-甘露聚糖酶进行定向突变获得酶活性和稳定性提高的酶。应用PCR方法对Bacillus licheniformis KD-1 β-甘露聚糖酶基因manBl进行基因克隆和定点突变,在枯草芽孢杆菌B. subtilis DB104中进行分泌表达,采用二硝基水杨酸(DNS)法进行酶活性测定。β-甘露聚糖酶ManBl及6个突变体最适pH 6.0,最适温度60℃,6个突变体比活力和pH 6.0-10.0 之间的pH稳定性均高于野生型,突变体ManBlT112R/K291E)比活力是野生型的2.6倍,为(9 742±370.0)U/mg,Km值为2.67 mg/mL,70℃的半衰期为80 min;C-末端带有His标签后,ManBl和ManBlT112R/K291E)的酶活性和热稳定性降低。β-甘露聚糖突变体ManBlT112R/K291E)酶活性和稳定性高,适合在养殖业、食品加工和洗涤业等多种工业领域中应用。

关键词: β-甘露聚糖酶, 地衣芽孢杆菌, 定点突变, 酶活性, 稳定性

Abstract:

The β-mannanase gene from Bacillus licheniformis strain KD-1 was directed mutated for improving its activity and stability. The β-mannanase gene manBl from B. licheniformis strain KD-1 was cloned and directed mutated by PCR. The gene and its mutants were expressed in B. subtilis DB104. The activities of the enzymes were measured by dinitrosalicylic acid,and DNS method. The β-mannanase ManBl and its 6 variants had the same optimal pH 6.0 and optimal temperature 60℃. All the variants had higher specific activity and pH stability between pH 6.0-10.0 than wild-type ManBl. The specific activity of the mutant ManBlT112R/K291E)was(9 742±370.0)U/mg,which was 2.6 times of wild-type ManBl. The Km value of ManBlT112R/K291E)was 2.67 mg/mL. The half-life of ManBl(T112R/K291E)was 80 min at 70℃. The two enzymes with 6×His-tagged at the C terminal had lower specific activity and thermostability than the corresponding enzyme without His-tag. The β-mannanase mutant ManBlT112R/K291E)shows potential application in feed,food and laundry industrial fields with its high specific activity,pH stability and thermostability.

Key words: β-mannanase, Bacillus licheniformis, directed mutation, enzyme activity, stability