Membrane electrochemical reactors (MER) for NADH regeneration in HLADH-catalysed synthesis: comparison of effectiveness

Délécouls-Servat, K; Bergel, Alain; Basseguy, Régine

doi:10.1007/s00449-004-0356-2

Cited by 27 publications

(4 citation statements)

References 42 publications

(39 reference statements)

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“…Economically, to maximize the involving of cofactors, regeneration and recycling of the coenzyme within the enzyme reactor is often required. Engineering to generate the NAD(H) in a reaction has been performed by using both electrochemical 6 and photosensitized electron transfer 7 . However, the most common methods used are based on enzymatic regeneration 8 , 9 .…”

Section: Introductionmentioning

confidence: 99%

NAD(H) recycling activity of an engineered bifunctional enzyme galactose dehydrogenase/lactate dehydrogenase

Prachayasittikul¹,

Ljung²,

Isarankura‐Na‐Ayudhya³

et al. 2006

Int. J. Biol. Sci.

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A chimeric bifunctional enzyme composing of galactose dehydrogenase (galDH; from Pseudomonas fluorescens) and lactate dehydrogenase (LDH; from Bacillus stearothermophilus) was successfully constructed. The chimeric galDH/LDH possessed dual characteristics of both galactose dehydrogenase and lactate dehydrogenase activities while exhibiting hexameric rearrangement with a molecular weight of approximately 400 kDa. In vitro observations showed that the chimeric enzyme was able to recycle NAD with a continuous production of lactate without any externally added NADH. Two fold higher recycling rate (0.3 mM/h) than that of the native enzyme was observed at pH values above 8.5. Proximity effects became especially pronounced during the recycling assay when diffusion hindrance was induced by polyethylene glycol. All these findings open up a high feasibility to apply the NAD(H) recycling system for metabolic engineering purposes e.g. as a model to gain a better understanding on the molecular proximity process and as the routes for synthesizing of numerous high-value-added compounds.

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Section: Introductionmentioning

confidence: 99%

NAD(H) recycling activity of an engineered bifunctional enzyme galactose dehydrogenase/lactate dehydrogenase

Prachayasittikul¹,

Ljung²,

Isarankura‐Na‐Ayudhya³

et al. 2006

Int. J. Biol. Sci.

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“…So different methods were checked such as a combined CV and chronoamperometry (CA) measurement where two different potentials were analyzed during the chronoamperometric experiments: −0.4 V and −0.5 V vs. NHE. According to Délécombs-Servat et al 29 a ratio of mediator to NADH of 1:2 should lead to better results. So, different samples were prepared with a ratio of 1:1 and 1:2.…”

Section: Resultsmentioning

confidence: 98%

Electrochemical Screening of Redox Mediators for Electrochemical Regeneration of NADH

Gajdzik

Lenz

Natter

et al. 2011

J. Electrochem. Soc.

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We report the electrochemical cofactor regeneration for electroenzymatic reduction as a promising alternative to the enzymatic recycling due to the avoidance of couple products. In the mediated electron transfer reaction appropriate redox mediators for the cofactor reduction are necessary. We have synthesized different redox mediators-based on rhodium complexes-and have screened their electrochemical performance at different pH values and concentrations. Suitable mediators have been tested in the presence of the cofactor NAD + and then additionally in the presence of D-sorbitol dehydrogenase (DSDH) from Rhodobacter sphaeroides. The electroenzymatically generated product was analyzed by HPLC. As result of the screening some mediator species were identified which enable an efficient electrochemical cofactor reduction.Biofunctionalization of metal surfaces is widely used in the field of analytical applications especially in clinical diagnostics or for biofuel cells. 1-3 But electrochemical cofactor regeneration can also be important for preparative applications like synthesis of enantiomerically pure fine chemicals as synthons in the pharmaceutical industry. Especially for the preparative conversion with dehydrogenases, which implies a mediated electron transfer from the enzyme to the electrode, a cofactor and a redox mediator are necessary. The redox mediator decreases the potential for the NAD + reduction which amounts to about −1.0 V vs. NHE at bare electrodes without mediator. 4 For preparative syntheses only catalytic amounts of the cofactor NAD + /NADH are necessary which can be recycled in an enzymatic way. 5 A promising alternative represents the electrochemical cofactor regeneration which is already extensively known for the electrochemical re-oxidation of NADH by the functionalization of metal surfaces with biomolecules in the research of biosensors and biofuel cells 6-9 but only few mediators for reduction of NAD + are known. Numerous mediators likely to oxidize NADH (i.e., NAD + regeneration) have been reported. 10 For example, the regeneration of NAD + cofactor by a nitro fluorenone redox mediator was intensively investigated by Mano and co-workers. [11][12][13] In this case, the redox mediator was covalently bound to a gold surface and the cofactor was attached to the mediator by electrostatic forces via calcium bridges. This has been notably applied in the field of bioelectrocatalysis using a modified variant of a dehydrogenase for electroenzymatic oxidation reactions 14 on the basis of a cysteine modified galactitol dehydrogenase from Rhodobacter spaeroides, which was directly immobilized onto a gold surface, leading to successful electrochemical regeneration of the cofactor.On the other hand, elaborating redox mediators enabling the onestep transfer of two electrons (or one hydride) to NAD + species to regenerate directly the active form of the reduced cofactor (i.e., 1,4-NADH) is not an easy task as such mediator should react with NAD + and not transferring directly the electrons (or hydride ion) t...

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“…The D-MER has been described elsewhere [3,4,8]. The working and auxiliary platinum grid electrodes (196 mesh cm )2 , Engelhard-CLAL) have 30 cm 2 surface area.…”

Section: Methodsmentioning

confidence: 99%

Glucose oxidase catalysed oxidation of glucose in a dialysis membrane electrochemical reactor (D-MER)

Basseguy

Délécouls-Servat

Bergel

2004

Bioprocess and Biosystems Engineering

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The purpose of this work was to evaluate the effectiveness of a new Membrane Electrochemical Reactor (MER) for the production of gluconic acid by glucose oxidase (GOD) catalysed glucose oxidation. The GOD was confined against the electrode surface with a dialysis membrane. The role of the electrochemical step was to eliminate by oxidation the hydrogen peroxide that appeared as a by-product of the reaction and strongly inhibited and/or inactivated GOD. The dialysis MER gave a transformation ratio of 30% with an initial glucose concentration of around 300 mM. This result is significantly better than the maximum of 10% obtained when hydrogen peroxide was eliminated by addition of a large excess of catalase in solution, as is generally done. The D-MER also revealed unexpected properties of the enzyme kinetics, such as an oscillatory behaviour, which were discussed.

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Membrane electrochemical reactors (MER) for NADH regeneration in HLADH-catalysed synthesis: comparison of effectiveness

Cited by 27 publications

References 42 publications

NAD(H) recycling activity of an engineered bifunctional enzyme galactose dehydrogenase/lactate dehydrogenase

NAD(H) recycling activity of an engineered bifunctional enzyme galactose dehydrogenase/lactate dehydrogenase

Electrochemical Screening of Redox Mediators for Electrochemical Regeneration of NADH

Glucose oxidase catalysed oxidation of glucose in a dialysis membrane electrochemical reactor (D-MER)

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