Immobilized redox mediators for electrochemical NAD(P)+ regeneration

Kochius, Svenja; Magnusson, Anders O.; Hollmann, Frank; Schrader, Jens; Holtmann, Dirk

doi:10.1007/s00253-012-3900-z

Cited by 78 publications

(56 citation statements)

References 118 publications

(144 reference statements)

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“…Moreover, electrochemical cofactor regeneration has been exploited towards fine-chemical and bioenergy production 45 and a large number of mediator systems have been introduced for efficient electron transfer between electrode and enzyme 46 . Single-step biotransformations with electrochemical cofactor recycling are well established, in particular in the area of redox biocatalysis 47 , and further facilitated by new technologies such as microfluidic systems 48 .…”

Section: Review Articlementioning

confidence: 99%

Opportunities and challenges for combining chemo- and biocatalysis

et al. 2018

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N ature has evolved highly efficient systems in the form of cascade reactions, which assemble the metabolic networks that support life (growth and survival). The basic principle of cascade reactions is also frequently used in biocatalysis, using enzymes in isolation, as well as in combination with chemocatalysts (see Fig. 1 and Box 1 for definition of terms) [1][2][3][4][5][6][7] . As there is no need for purification and isolation of intermediates, operating time, production costs and waste are reduced, and concomitantly, overall yields are improved. In addition, the problem of unstable or difficult to handle intermediates can be overcome, and reactivity as well as selectivity can be enhanced by avoiding unfavourable reaction equilibria through the cooperative effects of multiple catalysts 8 . Starting in the 1980s, the early examples of the combination of chemo-and biocatalysts were reported by the van Bekkum group, who pioneered the development of a process to make the sugar substitute d-mannitol from readily available d-glucose through the combination of a heterogeneous metal-catalysed hydrogenation and an enzyme-catalysed isomerization 9 . The first broadly applied technology for the combination of enzyme and metalcatalysts, which was the research subject of many academic groups as well as industry, emerged in the 1990s from the Williams group 10,11 and aimed to achieve higher yields than classical kinetic resolution of racemates, thus overcoming the limitation of a maximum yield of 50% in the latter case. A prominent example of work that developed this theme is the combination of lipase-catalysed kinetic resolution via acylation of secondary alcohols with Pd-or Rh-catalysed racemization via reversible transfer hydrogenation to achieve a dynamic kinetic resolution (DKR) [12][13][14] . This example was facilitated in part because lipases are active and stable in organic solvents. Later, for instance, Turner's group combined a monoamine oxidase-catalysed imine formation with a chemical reduction 15 to achieve the 100% theoretical yield through a deracemization process. In addition to the combination of metalcatalysis with enzymes, organocatalysis, electrochemistry and light-induced reaction couples have since then been studied extensively, going far beyond the scope of a DKR.The challenges to combining chemo-and biocatalysis in cascades (see Box 1 for definitions and Table 1) can be daunting, not least the requirement for the chemical step to occur in the presence of water, the preferred solvent for enzymes 3 . This Review therefore highlights recent examples of the combination of chemo-and biocatalysts in aqueous multistep syntheses, and looks at how to overcome limitations by, for example, design of appropriate reaction conditions, protein engineering and advanced reactor concepts. Furthermore, trends such as the integration of transition metalcatalysis into microorganisms and the introduction of novel chemistry into engineered enzymes are discussed, and a critical assessment of the impact of this research ...

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Section: Review Articlementioning

confidence: 99%

Opportunities and challenges for combining chemo- and biocatalysis

et al. 2018

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“…9,14,52 We spotted 70 μL of an aqueous solution of 0.5 mg/mL 1,10-PD onto the detection zone, and allowed the device to dry for overnight at room temperature in the dark (1,10-PD in solution is sensitive to light). Next, 45 μL of the enzyme and cofactor solution containing 2 U/mL of 3-HBDH and 42 mM NAD + in Tris-buffer were added to the reaction zone.…”

Section: Resultsmentioning

confidence: 99%

A Paper-Based “Pop-up” Electrochemical Device for Analysis of Beta-Hydroxybutyrate

et al. 2016

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This paper describes the design and fabrication of a “pop-up” electrochemical paper-based analytical device (pop-up-EPAD) to measure beta-hydroxybutyrate (BHB)—a key biomarker for diabetic ketoacidosis—using a commercial glucometer. Pop-up-EPADs are inspired by pop-up greeting cards and children’s books. They are made from a single sheet of paper folded into a three-dimensional (3D) device that changes shape, and fluidic and electrical connectivity, by simply folding and unfolding the structure. The reconfigurable 3D structure makes it possible to change the fluidic path and to control timing; it also provides mechanical support for the folded and unfolded structures that enables good registration and repeatability on folding. A pop-up-EPAD designed to detect BHB shows performance comparable to commercially available plastic test strips over the clinically relevant range of BHB in blood when used with a commercial glucometer that integrates the ability to measure glucose and BHB (combination BHB/glucometer). With simple modifications of the electrode and fluid path design, the pop-up-EPAD also detects BHB using a simple glucometer—a device that is much more available than combination BHB/glucometers. Strategies that use a “3D pop-up”—that is, large-scale changes a 3D structure and fluidic paths—by folding/unfolding add functionality (e.g., controlled timing, fluidic handling and path programming, control over complex sequences of steps, and alterations in electrical connectivity) to EPADs, and should enable the development of new classes of paper-based diagnostic devices.

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“…GDH activity was modeled by sequential ordered bi-bi mechanism kinetics with the coenzyme binding first [24]. The product of the laccase reaction, the oxidized redox mediator, reacts with one of the products of the GDH reaction, the reduced nicotinamide coenzyme, in a second-order reaction [5] (this work). The reaction rates for laccase (r 1 ), the redox mediator/NAD(P)H (r 2 ) and GDH (r 3 ) are given by the Eqs.…”

Section: Rate Equation and Matlab Modelmentioning

confidence: 99%

“…synthetic enzyme [5]. High costs have been an obstacle in the wider application of coenzyme-dependent oxidreductases, but this is also the strongest argument for applying efficient and economical coenzyme regeneration systems.…”

Section: Introductionmentioning

confidence: 99%

Engineering an enzymatic regeneration system for NAD(P)H oxidation

Pham

Hollmann

Kracher

et al. 2015

Journal of Molecular Catalysis B: Enzymatic

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a b s t r a c tA recently proposed coenzyme regeneration system employing laccase and a number of various redox mediators for the oxidation of NAD(P)H was studied in detail by kinetic characterization of individual reaction steps. Reaction engineering by modeling was used to optimize the employed enzyme, coenzyme as well as redox mediator concentrations. Glucose dehydrogenase from Bacillus sp. served as a convenient model of synthetic enzymes that depend either on NAD + or NADP + . The suitability of laccase from Trametes pubescens in combination with acetosyringone or syringaldazine as redox mediator was tested for the regeneration (oxidation) of both coenzymes. In a first step, pH profiles and catalytic constants of laccase for the redox mediators were determined. Then, second-order rate constants for the oxidation of NAD(P)H by the redox mediators were measured. In a third step, the rate equation for the entire enzymatic process was derived and used to build a MATLAB model. After verifying the agreement of predicted vs. experimental data, the model was used to calculate different scenarios employing varying concentrations of regeneration system components. The modeled processes were experimentally tested and the results compared to the predictions. It was found that the regeneration of NADH to its oxidized form was performed very efficiently, but that an excess of laccase activity leads to a high concentration of the oxidized form of the redox mediator -a phenoxy radical -which initiates coupling (dimerization or polymerization) and enzyme deactivation.

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Immobilized redox mediators for electrochemical NAD(P)+ regeneration

Cited by 78 publications

References 118 publications

Opportunities and challenges for combining chemo- and biocatalysis

Opportunities and challenges for combining chemo- and biocatalysis

A Paper-Based “Pop-up” Electrochemical Device for Analysis of Beta-Hydroxybutyrate

Engineering an enzymatic regeneration system for NAD(P)H oxidation

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