生物技术通报 ›› 2014, Vol. 0 ›› Issue (6): 181-186.

• 研究报告 • 上一篇    下一篇

黑曲霉嗜热β-甘露聚糖酶在毕赤酵母中的克隆表达及其魔芋降解产物分析

倪玉佳1, 周旻昱2, 欧阳嘉1,3, 郑兆娟1, 勇强1   

  1. (1.南京林业大学化学工程学院,南京 210037;2.南京林业大学森林资源与环境学院,南京 210037;3.江苏省生物质绿色燃料与化学品重点实验室,南京 210037)
  • 收稿日期:2013-11-20 出版日期:2014-06-25 发布日期:2014-06-25
  • 作者简介:倪玉佳,女,硕士研究生,研究方向:生物化工;E-mail:523869088@qq.com
  • 基金资助:
    国家林业公益性行业科研专项(201404615),教育部新世纪优秀人才支持计划(NCET-11-0988),江苏省杰出青年基金(BK2012038),江苏省高校优势学科建设工程资助项目(PAPD)

Cloning,Expression of Thermostable β-mannanase and the Preparation of Mannooligosaccharide

Ni Yujia1,Zhou Minyu2,Ouyang Jia1,3,Zheng Zhaojuan1,Yong Qiang1   

  1. (1. College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037;2. College of Forest Resource & Environment, Nanjing Forestry University, Nanjing 210037;3. Jiangsu Key Lab of Biomass-based Green Fuels and Chemicals, Nanjing 210037)
  • Received:2013-11-20 Published:2014-06-25 Online:2014-06-25

摘要: 根据毕赤酵母密码子偏好性优化设计合成一段来自黑曲霉BK01的嗜热β-甘露聚糖酶基因,通过构建表达载体pPICZαA-man线性化后电转化入不同的毕赤酵母宿主,获得最佳重组菌KM71-MAN,其发酵罐发酵酶活最高达2 318.85 IU/mL。表达产物纯化后的分子量约为40 kD,最适反应温度为80℃,最适pH为5.0。该酶在70℃(pH5.0)保温44 h仍能保留43%的酶活力且在pH3.0-7.0范围内保温70 h(50℃)酶活力仍能保留85%以上。利用发酵罐所产重组酶酶解魔芋胶制备甘露低聚糖,产物以甘露二糖和甘露六糖为主,甘露低聚糖得率为55.6%。该重组β-甘露聚糖酶具有良好的热稳定性和pH稳定性,在魔芋制备甘露低聚糖中具有较好的应用潜能。

关键词: β-甘露聚糖酶, 密码子偏好性, 毕赤酵母, 酶学性质, 低聚甘露糖

Abstract: According to the Pichia pastoris’s codon preference, a DNA sequence encoding Aspergillus niger BK01 thermophilic β-mannanase gene was designed and synthesized. Firstly, it was inserted into pPICZαA and resulted in recombinant expression vector pPICZαA-man. Then, pPICZαA-man was linearized and transformed into different hosts by electrotransformation. An optimal recombinant stain KM71-MAN was obtained by screening activity. Using recombinant strain KM71-MAN, recombinant mannanase was overexpressed and its activity in the culture medium reached 2 318.85 IU/mL in a 3 L fermentor. Recombinant enzyme had an apparent molecular size of about 40 kD by SDS-PAGE, and optimal activity at pH 5.0 and 80℃. It was highly thermostable, retaining 43% of enzyme activity after 44 h of exposure at 70℃ and pH 5.0. Moreover, it remained over 85% activity from pH 3.0 to pH 7.0 after treating at 50℃ for 70 h. Using this crude enzyme, the main hydrolysis products yielded from konjak gum were mannobiose and mannohexaose and the yield of mannooligosaccharides was 55.6%. The recombinant enzyme exhibited good thermal and pH stability, which indicated that the recombinant yeast has potential value in preparation of konjac gum mannooligosaccharides.

Key words: β-mannanase, Codon preference, Pichia pastoris, Enzymatic properties, Mannooligosaccharide