食品科学 ›› 2022, Vol. 43 ›› Issue (10): 73-80.doi: 10.7506/spkx1002-6630-20210604-049

• 生物工程 • 上一篇    下一篇

源于Bacillus megaterium STB10的直链麦芽五糖生成酶酶学性质及其产物合成规律

韩煦,班宵逢,李才明,顾正彪,李兆丰   

  1. (江南大学食品学院,江苏 无锡 214122)
  • 出版日期:2022-05-25 发布日期:2022-05-27
  • 基金资助:
    国家自然科学基金面上项目(31571882);国家食品科学与工程一流学科建设项目(JUFSTR20180204)

Enzymatic Properties and Product Synthesis Pattern of Maltopentaose-forming Amylase from Bacillus megaterium STB10

HAN Xu, BAN Xiaofeng, LI Caiming, GU Zhengbiao, LI Zhaofeng   

  1. (School of Food Science and Technology, Jiangnan University, Wuxi 214122, China)
  • Online:2022-05-25 Published:2022-05-27

摘要: 构建来源于巨大芽孢杆菌STB10直链麦芽五糖生成酶(Bacillus megaterium maltopentaose-forming amylase,BmMFA)的食品级枯草芽孢杆菌表达系统,实现了该酶的分泌表达,分析了其酶学性质,并对其产物合成规律进行了探究。结果显示,BmMFA具有较强的催化活力,枯草芽孢杆菌发酵后上清液中酶活力可达196.57 U/mL;该酶的最适反应温度为50 ℃,最适反应pH值为7.0,且具有相对较宽的pH值应用范围;BmMFA倾向于内切酶作用机制,且具有较好的产物特异性,水解麦芽糊精24 h后产物中直链麦芽五糖质量分数42%以上,当以支链淀粉为底物时,其转化率及主产物直链麦芽五糖比例均优于直链淀粉。本研究为直链麦芽五糖的酶法制备提供了一定的理论依据。

关键词: 直链麦芽五糖;直链麦芽五糖生成酶;酶学性质;产物合成;产物特异性

Abstract: This study established a food-grade Bacillus subtilis expression system for a maltopentaose-forming amylase derived from Bacillus megaterium STB10 (BmMFA). The enzymatic properties and product synthesis pattern of the expressed enzyme were studied. Results showed that BmMFAse exhibited excellent catalytic activity, and the enzymatic activity in the fermentation supernatant of B. subtilis was 196.57?U/mL. The optimal reaction temperature and pH of BmMFA were 50 ℃ and pH 7.0, respectively, and BmMFAse could adapt to a wide pH range. The action pattern of BmMFA was found to tend to be endo-type. BmMFAse showed superior product specificity, and the maltopentaose content in maltodextrin hydrolyzed by BmMFAse for 24?h was over 42%. The substrate conversion rate and the relative content of maltopentaose as the major product were higher using amylopectin as the substrate for BmMFA than amylose. This study provides a theoretical basis for the efficient production of maltopentaose.

Key words: maltopentaose; maltopentaose-forming amylase; enzymatic properties; product synthesis; product specificity

中图分类号: