Regeneration of NAD(+) cofactor by photosensitized electron transfer in an immobilized alcohol dehydrogenase system.
The irradiation with visible light of a photosensitizer dye like methylene blue was used to regenerate by electron transfer the oxidized form of a pyridine nucleotide coenzyme (NAD(+)). The process has been studied on a common enzymatic reaction: ethanol oxidation by alcohol-NAD(+) oxidoreductase immobilized on polyacrylamide gel or porous glass balls. In the experimental conditions used, the initial NAD(+) recycling rates were 2.33 x 10(4) cycles/h (polyacrylamide) and 3 x 10(4) cycles/h (glass balls). A total number of 49.5 x 10(4) cycles was obtained for 13 runs of 2 h. The enzyme immobilization strongly increased its stability: after 28 days at 20 degrees C, the residual activity was 25% of the initial value.
Laboratoire de Chimie Moléculaire et de Pétroléochimie, Associé au CNRS UA 126, Faculté des Sciences et Techniques de Saint-Jérôme, Rue Henri Poincaré, 13397 Marseille Cedex 13, France.
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Julliard
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Le Petit
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Ritz