Efficient production of (R)-(−)-mandelic acid using glutaraldehyde cross-linked Escherichia coli cells expressing Alcaligenes sp. nitrilase
Efficient production of (R)-(−)-mandelic acid using glutaraldehyde cross-linked Escherichia coli cells expressing Alcaligenes sp. nitrilase
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DOI：
10.1007/s00449-013-1096-y
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发表时间：
2014-07
影响因子：
3.8
通讯作者：
Zhi‐Jun Zhang;Jiang Pan;Chun-Xiu Li;Huilei Yu;G. Zheng;X. Ju;Jian‐He Xu
中科院分区：
文献类型：
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作者：
Zhi‐Jun Zhang;Jiang Pan;Chun-Xiu Li;Huilei Yu;G. Zheng;X. Ju;Jian‐He Xu
表达Alcaligenessp的重组大肠杆菌细胞。使用戊二醛通过直接交联简单地固定腈水解酶。在最佳交联条件下，约 85% 的总腈水解酶活性得到恢复。在 30、40 和 50 °C 下测量的交联电池的热稳定性分别是游离电池的 4.5、5.3 和 5.1 倍。使用 300 mM 扁桃腈作为底物，仅 2 小时转化固定化细胞后，(R)-(−)-扁桃酸的浓度就达到 280 mM，产生 510.7 g L−1d−1 的极高生产率。此外，固定化细胞的操作稳定性明显优于游离细胞，在15个循环的分批反应或8个循环的重复补料分批反应后没有明显的活性损失。因此，固定化生物催化剂的易于制备和稳健的特性使其成为一种非常有前途的生物催化剂，用于高性能和低成本生产光学纯(R)-(−)-扁桃酸。
RecombinantEscherichia colicells expressingAlcaligenessp. nitrilase were simply immobilized by direct cross-linking using glutaraldehyde. About 85 % of the total nitrilase activity was recovered under the optimal cross-linking conditions. The thermal stabilities of the cross-linked cells measured at 30, 40 and 50 °C were 4.5-, 5.3-, and 5.1-fold those of the free cells, respectively. The concentration of (R)-(−)-mandelic acid reached 280 mM after merely 2 h transformation with the immobilized cells using 300 mM mandelonitrile as substrate, affording an extremely high productivity of 510.7 g L−1d−1. In addition, operational stability of the immobilized cells was obviously superior to that of free cells, without significant activity loss after 15 cycles of batch reactions or 8 cycles of repeated fed-batch reactions. Therefore, the easy preparation and robust characteristics of the immobilized biocatalyst make it a very promising biocatalyst for high-performance and low-cost production of optically pure (R)-(−)-mandelic acid.