食品科学 ›› 2019, Vol. 40 ›› Issue (8): 73-78.doi: 10.7506/spkx1002-6630-20180507-064

• 生物工程 • 上一篇    下一篇

毕赤酵母表达解淀粉芽孢杆菌壳聚糖酶及其水解制备可控结构壳寡糖

程 功,焦思明,冯 翠,贾培媛,任立世,杜昱光   

  1. 中国科学院过程工程研究所 生化工程国家重点实验室,北京 100190
  • 出版日期:2019-04-25 发布日期:2019-05-05
  • 基金资助:
    “十三五”国家重点研发计划重点专项(2016YFB0301502);国家自然科学基金联合基金项目(U1608255)

Expression of Chitosanase from Bacillus amyloliquefaciens in Pichia pastoris and Its Application in Preparation of Chitooligosaccharides with Controllable Structure

CHENG Gong, JIAO Siming, FENG Cui, JIA Peiyuan, REN Lishi, DU Yuguang   

  1. State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
  • Online:2019-04-25 Published:2019-05-05

摘要: 优化并全合成解淀粉芽孢杆菌(Bacillus amyloliquefaciens)壳聚糖酶编码基因并在毕赤酵母(Pichia pastoris)中实现分泌表达,表达产物的蛋白质量浓度达到0.23 mg/mL。壳聚糖水解酶的最适pH值为5.0,最适温度为45 ℃,比活力达52.2 U/mL。该酶在50 ℃以下较稳定。利用该酶水解低脱乙酰度壳聚糖并对产物进行了组成及结构分析。基质辅助激光解吸电离飞行时间质谱分析结果显示,酶解产物中包含聚合度3~15、不同脱乙酰度的壳寡糖。核磁共振鉴定结果显示,壳寡糖组分的还原末端及非还原末端均主要由氨基葡萄糖组成。综上,本研究高效表达了来源于解淀粉芽孢杆菌的壳聚糖酶,并制备了确定末端结构的壳寡糖,为壳寡糖的结构与功能关系研究提供理论支持。

关键词: 毕赤酵母, 解淀粉芽孢杆菌, 壳聚糖酶, 壳寡糖, 基质辅助激光解吸电离飞行时间质谱, 核磁共振

Abstract: The chitosanase-encoding gene of Bacillus amyloliquefaciens was optimized, synthesized and expressed in Pichia pastoris. The protein concentration of the expressed product was 0.23 mg/mL. The optimum pH and temperature of the enzyme were 5.0 and 45 ℃, respectively, and the specific activity reached 52.2 U/mL. The chitosanase was continuously thermo-stable at 50 ℃. Chitosan with low deacetylation was hydrolyzed by this enzyme and the composition and structure of the hydrolysate were analyzed. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDITOF MS) analysis showed that this hydrolysate contained chitooligosaccharides with degree of polymerization of 3–15 and different degrees of deacetylation. Nuclear magnetic resonance (NMR) results indicated that both the reducing and nonreducing ends of oligosaccharide fractions were mainly composed of glucosamine. In summary, we efficiently expressed chitosanase from B. amyloliquefaciens and prepared chitooligosaccharides with determined terminal structures, which will lay a theoretical foundation for the study of the structure-function relationship of chitooligosaccharides.

Key words: Bacillus amyloliquefaciens, chitosanase, Pichia pastoris, chitooligosaccharides, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS), nuclear magnetic resonance (NMR)

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