Oxygen supply to biocatalytic oxidations

Oxygen-dependent enzymes are becoming increasingly relevant in the synthesis of fine chemicals, flavours and fragrances as well as pharmaceutical intermediates. Oxidases are a notable subclass of oxidizing enzymes, which use molecular oxygen either as an oxidant or as an electron acceptor. This property makes them highly attractive for industrial manufacturing processes, avoiding the use of harmful metal oxidants However, supplying molecular oxygen with high transfer rates is still a major challenge when high reaction productivities need to be achieved to develop an economic feasible process. Commonly, bioreactors supply oxygen by sparging air into the reaction medium and the resultant mass transfer of oxygen from the gas to the liquid phase has proved to be a limiting factor due to the poor solubility of oxygen in water and since high oxygen demand is needed to achieve adequate reaction productivities (1). Furthermore, enzyme stability might become an issue since oxidases may deactivate at a gas-liquid interface (2). Therefore, in order to develop robust processes using oxygen-dependent enzymes, there is a necessity to quantify the oxygen affinity of the enzyme, explore the enzyme stability and quantify how fast the oxygen needs to be supplied to achieve high productivities. This can be done by characterizing the enzyme under relevant conditions for an industrial process. This contribution is focused on the characterization of enzyme and reaction kinetics of oxygen-dependent biocatalysts, with emphasis on the oxygen requirements, in order to provide guidance for the design and development of oxidative biocatalytic processes. The influence of KMO (kinetic Michaelis constant for oxygen) on enzyme efficiency will be discussed (3) as well as process limitations of oxygen transfer. Van Hecke W, Ludwig R, Dewulf J, Auly M, Messiaen T, Haltrich D, et al. Bubble-free oxygenation of a bi-enzymatic system: Effect on biocatalyst stability. Biotechnol Bioeng. 2009;102(1):122–31. Bommarius AS, Karau A. Deactivation of Formate Dehydrogenase (FDH) in solution and at gas-liquid interfaces. Biotechnol Prog. 2005;21(6):1663–72. Toftgaard Pedersen A, Birmingham WR, Rehn G, Charnock SJ, Turner NJ, Woodley JM. Process requirements of galactose oxidase catalyzed oxidation of alcohols. Org Process Res Dev. 2015;19:1580–9

Toward scalable biocatalytic conversion of 5-hydroxymethylfurfural by galactose oxidase using coordinated reaction and enzyme engineering

5-Hydroxymethylfurfural (HMF) can be transformed to a range of industrially useful derivatives, such as 2,5-diformylfuran (DFF), but the reactions needed for efficient industrial production are hindered by several issues. Here, the authors perform reaction and enzyme engineering resulting in a galactose oxidase variant with high activity towards HMF, improved oxygen binding and high productivity

Toward scalable biocatalytic conversion of 5-hydroxymethylfurfural by galactose oxidase using coordinated reaction and enzyme engineering

From Springer Nature via Jisc Publications RouterHistory: received 2020-12-09, accepted 2021-07-06, registration 2021-07-21, pub-electronic 2021-08-16, online 2021-08-16, collection 2021-12Publication status: PublishedFunder: EC | EC Seventh Framework Programm | FP7 Food, Agriculture and Fisheries, Biotechnology (FP7-KBBE - Specific Programme "Cooperation": Food, Agriculture and Fisheries, Biotechnology); doi: https://doi.org/10.13039/100011262; Grant(s): 613849Abstract: 5-Hydroxymethylfurfural (HMF) has emerged as a crucial bio-based chemical building block in the drive towards developing materials from renewable resources, due to its direct preparation from sugars and its readily diversifiable scaffold. A key obstacle in transitioning to bio-based plastic production lies in meeting the necessary industrial production efficiency, particularly in the cost-effective conversion of HMF to valuable intermediates. Toward addressing the challenge of developing scalable technology for oxidizing crude HMF to more valuable chemicals, here we report coordinated reaction and enzyme engineering to provide a galactose oxidase (GOase) variant with remarkably high activity toward HMF, improved O2 binding and excellent productivity (>1,000,000 TTN). The biocatalyst and reaction conditions presented here for GOase catalysed selective oxidation of HMF to 2,5-diformylfuran offers a productive blueprint for further development, giving hope for the creation of a biocatalytic route to scalable production of furan-based chemical building blocks from sustainable feedstocks