National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, PR China; Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou 310014, PR China; Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, China.
Int J Biol Macromol. 2019 Jun 1;130:117-124. doi: 10.1016/j.ijbiomac.2019.02.131. Epub 2019 Feb 23.
Nitrilase-catalyzed regioselective hydrolysis of 1-cyanocyclohexaneacetonitrile (1-CHAN) is a green and efficient approach for the preparation of 1-cyanocyclohexaneacetic acid (1-CHAA), a key precursor for the synthesis of gabapentin. Here, a mesoporous biosilica particles prepared by the ethyleneamine-mediated silicification have been used as carrier for the encapsulation of nitrilase from Acidovorax facilis (NitA). The silica-encapsulated NitA (NitA@silica) with triethylenetetramine as an initiator showed the highest immobilization efficiency (98.3%) and specific activity (672.6 U/g). Both free and encapsulated NitA were optimally active at 40 °C and pH 7.0, however, the encapsulated enzyme exhibited wider optimum temperature range, and enhanced thermal stability compared with the free enzyme. The kinetic parameters K and V for free and encapsulated NitA were calculated to be 141 mM and 9.97 mM min, and 280 mM and 9.02 mM min, respectively. The encapsulated NitA showed good reusability and retained about 94.2% of its initial activity even after 16 cycles of reaction. Also, the storage experiments revealed high activity maintenance of encapsulated NitA after 17-day storage at 4 °C. A preparative scale regioselective hydrolysis of 1-CHAN to 1-CHAA with encapsulated NitA as biocatalyst was carried out in a 2 L stirred bioreactor. The concentration of 1-CHAA reached 152 g/L after 8 h reaction and the conversion was 90.9%. These results showed that the encapsulation of NitA in ethyleneamine-mediated biosilica is an efficient and simple way for preparation of stable nitrilase and have a great potential for application in enzymatic production of carboxylic acids.
腈水解酶催化 1-氰基环己烷乙腈(1-CHAN)的区域选择性水解是制备 1-氰基环己烷乙酸(1-CHAA)的绿色、高效方法,1-CHAA 是加巴喷丁合成的关键前体。在此,通过乙二胺介导的硅烷化制备的介孔生物硅颗粒被用作固载腈水解酶的载体,该酶来源于 Acidovorax facilis(NitA)。以三乙烯四胺为引发剂,硅烷化得到的硅包裹 NitA(NitA@silica)具有最高的固定化效率(98.3%)和比活性(672.6 U/g)。游离态和固定化态的 NitA 均在 40°C 和 pH 7.0 下表现出最佳活性,但与游离态酶相比,固定化酶的最适温度范围更宽,热稳定性更高。游离态和固定化态的 NitA 的动力学参数 K 和 V 分别计算为 141 mM 和 9.97 mM·min-1,以及 280 mM 和 9.02 mM·min-1。固定化态的 NitA 具有良好的可重复使用性,在 16 次反应循环后仍保留初始活性的 94.2%。此外,储存实验表明,在 4°C 下储存 17 天后,固定化态的 NitA 仍具有较高的活性。以固定化态的 NitA 为生物催化剂,在 2 L 搅拌式生物反应器中进行了 1-CHAN 的区域选择性水解制备 1-CHAA 的制备规模实验。反应 8 h 后,1-CHAA 的浓度达到 152 g/L,转化率为 90.9%。这些结果表明,在乙二胺介导的生物硅中固定化 NitA 是制备稳定的腈水解酶的一种有效且简单的方法,在羧酸的酶法生产中具有很大的应用潜力。
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