Abstract：
Upgrading biomass-derived bioethanol to higher-order alcohols using conventional biotechnological approaches is challenging. Herein, a novel, magnetic metal-organic-framework-based cofactor regeneration system was developed using ethanol dehydrogenase (EtDH:D46G), NADH oxidase (NOX), formolase (FLS:L482S), and nicotinamide adenine dinucleotide (NAD+) for converting rice straw-derived bioethanol to acetoin. A magnetic zeolitic imidazolate framework-8@Fe3O4/NAD+ (ZIF-8@Fe3O4/NAD+) regeneration system for cell-free cascade reactions was introduced and used to encapsulate EtDH:D46G, NOX, and FLS:L482S (ENF). ZIF-8@Fe3O4/NAD+ENF created an efficient microenvironment for three-step enzyme cascades. Under the optimized conditions, the yield of acetoin from 100 mM bioethanol using ZIF-8@Fe3O4/NAD+ENF was 90.4 %. The regeneration system showed 97.1 % thermostability at 50 °C. The free enzymes retained only 16.3 % residual conversion, compared with 91.2 % for ZIF-8@Fe3O4/NAD+ENF after ten cycles. The magnetic metal-organic-framework-based cofactor regeneration system is suitable for enzymatic cascade biotransformations and can be extended to other cascade systems for potential biotechnological applications.
摘要：
使用常规生物技术方法将生物质衍生的生物乙醇升级为高级醇具有挑战性。在这里，一本小说,使用乙醇脱氢酶（EtDH：D46G）开发了基于金属有机框架的磁性辅因子再生系统，NADH氧化酶(NOX),甲醛酶(FLS:L482S),和烟酰胺腺嘌呤二核苷酸（NAD），用于将稻草衍生的生物乙醇转化为丙酮。引入了用于无细胞级联反应的磁性沸石咪唑酯骨架-8@Fe3O4/NAD（ZIF-8@Fe3O4/NAD）再生系统，并用于封装EtDH：D46G，NOX,FLS：L482S（ENF）。ZIF-8@Fe3O4/NADENF为三步酶级联创建了有效的微环境。在优化条件下,使用ZIF-8@Fe3O4/NADENF从100mM生物乙醇中获得的乙偶酸的产率为90.4％。再生系统在50°C下显示97.1%的热稳定性游离酶只保留了16.3%的残余转化率，10次循环后，ZIF-8@Fe3O4/NAD+ENF为91.2%。基于磁性金属有机框架的辅因子再生系统适用于酶促级联生物转化，并且可以扩展到其他级联系统以用于潜在的生物技术应用。
