No abstract

Peroxygenases have long inspired the selective oxyfunctionalization of various aliphatic and aromatic compounds, because of their broad substrate spectrum and simplicity of catalytic mechanism. This study provides a proof-of-concept of piezobiocatalysis by demonstrating peroxygenase-catalyzed oxyfunctionalization reactions fueled by piezocatalytically generated H 2 O 2. Bismuth oxychloride (BiOCl) generated H 2 O 2 in situ via an oxygen reduction reaction under ultrasonic wave conditions. Through the simple combination of water, ultrasound, recombinant, evolved unspecific peroxygenase from Agrocybe aegerita (rAaeUPO), and BiOCl, the piezobiocatalytic platform accelerated selective hydroxylation of ethylbenzene to enantiopure (R)-1-phenylethanol [total turnover number of rAaeUPO (TTN rAaeUPO), 2002; turnover frequency, 77.7 min −1 ; >99% enantiomeric excess (ee)]. The BiOCl−rAaeUPO couple also catalyzed other representative substrates (e.g., propylbenzene, 1-chloro-4-ethylbenzene, cyclohexane, and cis-β-methylstyrene) with high turnover frequency and selectivity. We alleviated the oxidative stress of piezocatalytically generated OH • on rAaeUPO by spatial separation of rAaeUPO and BiOCl, which resulted in greatly enhanced TTN rAaeUPO of >3900 and the notable prolongation of reaction time. Overall, the BiOCl−rAaeUPO couple serves as a mechanical-to-chemical energy conversion platform for driving peroxygenase-catalyzed reactions under ultrasonic conditions.

We report visible light-driven, asymmetric hydrogenation of CC bonds using an ene-reductase from Thermus scotoductus SA-01 (TsOYE) and a light-harvesting dye (rose bengal, RB) co-immobilized in an alginate hydrogel. Highly efficient encapsulation of RB in alginate hydrogel was achieved using the intrinsic affinity between TsOYE and RB, which allowed for the construction of robust RB-TsOYEloaded alginate capsules. In the absence of NADH, the photobiocatalytic system facilitated asymmetric reduction of 2-methylcyclohexenone to an enantiopure (R)-2-methylcyclohexanone (ee > 99%; max. conversion, 70.4%; turnover frequency, 1.54 min −1 ; turnover number, 300.2) under illumination. A series of stability tests revealed a significant enhancement of TsOYE's robustness in alginate hydrogel against heat and chemical denaturants. This study provides insight into a greener and sustainable approach of cofactor-free OYE catalysis for producing value-added chemicals using light energy.

Heat is a fundamental feedstock, where more than 80% of global energy comes from fossil-based heating process. However, it is mostly wasted due to a lack of proper techniques of utilizing the low-quality waste heat (<100 °C). Here we report thermoelectrobiocatalytic chemical conversion systems for heat-fueled, enzyme-catalyzed oxyfunctionalization reactions. Thermoelectric bismuth telluride (Bi2Te3) directly converts low-temperature waste heat into chemical energy in the form of H2O2 near room temperature. The streamlined reaction scheme (e.g., water, heat, enzyme, and thermoelectric material) promotes enantio- and chemo-selective hydroxylation and epoxidation of representative substrates (e.g., ethylbenzene, propylbenzene, tetralin, cyclohexane, cis-β-methylstyrene), achieving a maximum total turnover number of rAaeUPO (TTNrAaeUPO) over 32000. Direct conversion of vehicle exhaust heat into the enantiopure enzymatic product with a rate of 231.4 μM h−1 during urban driving envisions the practical feasibility of thermoelectrobiocatalysis.