Miniaturizing Biocatalysis: Enzyme‐Catalyzed Reactions in an Aqueous/Organic Segmented Flow Capillary Microreactor

Abstract

AbstractA segmented flow capillary microreactor was used to perform the enzyme‐catalyzed conversion of 1‐heptaldehyde to 1‐heptanol in a two liquid‐liquid phase system. These reactor formats are established for chemical reactions but so far data describing the relevant system parameters for enzymatic catalysis are lacking. This work now addresses the impact of important parameters such as capillary diameter, flow velocity, phase ratio, and enzyme as well as substrate concentration on the performance of the enzymatic reaction under segmented flow conditions. All key parameters governing reaction performance have been correlated in a novel operational window for an easy assessment of the various system constraints. Such systems are characterized by high productivities and easy phase separation facilitating downstream processing. This work underscores the importance of segmented flow systems as a promising tool to perform multiphasic enzymatic catalysis. Abbreviations/Nomenclature: Da: Damköhler number; kcat: turnover number (s−1); eo: enzyme concentration (mM); φ: phase ratio; kL: mass transfer coefficient (m s−1); a: interfacial area per volume (m−1); CAe: equilibrium substrate concentration in the aqueous phase (mM); CAL: substrate concentration in the bulk aqueous phase (mM); rA: rate of reaction in the aqueous phase; mA: substrate mass transfer into the aqueous phase; STY: space time yield.