Harris Alexander W, Yehezkeli Omer, Hafenstine Glenn R, Goodwin Andrew P, Cha Jennifer N
Department of Chemical and Biological Engineering, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303, United States.
Materials Science and Engineering Program, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, Colorado 80303, United States.
ACS Sustain Chem Eng. 2017;5(9):8199-8204. doi: 10.1021/acssuschemeng.7b01849. Epub 2017 Jul 18.
This paper reports the design and preparation of a biohybrid photoelectrochemical cell (PEC) that can drive the tandem enzymatic oxidation and aldol condensation of -butanol (BuOH) to C 2-ethylhexenal (2-EH). In this work, BuOH was first oxidized to -butyraldehyde (BA) by the alcohol oxidase enzyme (AOx), concurrently generating hydrogen peroxide (HO). To preserve enzyme activity and increase kinetics nearly 2-fold, the HO was removed by oxidation at a bismuth vanadate (BiVO) photoanode. Organocatalyzed aldol condensation of C BA to C 2-EH improved the overall BuOH conversion to 6.2 ± 0.1% in a biased PEC after 16 h. A purely light-driven, unbiased PEC showed 3.1 ± 0.1% BuOH conversion, or ~50% of that obtained from the biased system. Replacing AOx with the enzyme alcohol dehydrogenase (ADH), which requires the diffusional nicotinamide adenine dinucleotide cofactor (NAD/NADH), resulted in only 0.2% BuOH conversion due to NAD dimerization at the photoanode. Lastly, the application of more positive biases with the biohybrid AOx PEC led to measurable production of H at the cathode, but at the cost of lower BA and 2-EH yields due to both product overoxidation and decreased enzyme activity.
本文报道了一种生物混合光电化学电池（PEC）的设计与制备，该电池能够驱动丁醇（BuOH）串联酶促氧化和羟醛缩合反应生成2-乙基己烯醛（2-EH）。在这项工作中，丁醇首先被醇氧化酶（AOx）氧化为丁醛（BA），同时生成过氧化氢（HO）。为了保持酶的活性并使反应动力学提高近2倍，通过在钒酸铋（BiVO）光阳极上进行氧化反应去除了HO。在偏置的PEC中，经有机催化将C BA缩合为C 2-EH，16小时后丁醇的总转化率提高到6.2±0.1%。纯光驱动、无偏置的PEC显示丁醇转化率为3.1±0.1%，约为偏置系统转化率的50%。用需要扩散性烟酰胺腺嘌呤二核苷酸辅因子（NAD/NADH）的醇脱氢酶（ADH）替代AOx，由于NAD在光阳极处二聚化，丁醇转化率仅为0.2%。最后，在生物混合AOx PEC中施加更正的偏压会导致阴极处有可测量的氢气产生，但由于产物过度氧化和酶活性降低，BA和2-EH的产率会降低。
