Authors: Mojca Božič Sina Pricelius Georg M Guebitz Vanja Kokol
Publish Date: 2009/08/07
Volume: 85, Issue: 3, Pages: 563-571
Abstract
Conventional vat dyeing involves chemical reduction of dyes into their watersoluble leuco form generating considerable amounts of toxic chemicals in effluents In the present study a new βnicotinamide adenine dinucleotide disodium salt NADHdependent reductase isolated from Bacillus subtilis was used to reduce the redox dyes CI Acid Blue 74 CI Natural Orange 6 and CI Vat Blue 1 into their watersoluble leuco form Enzymatic reduction was optimized in relation to pH and temperature conditions The reductase was able to reduce Acid Blue 74 and Natural Orange 6 in the presence of the stoichiometrically consumed cofactor NADH meanwhile Vat Blue 1 required the presence of mediator 18dihydroxyanthraquinone Oxygen from air was used to reoxidize the dyes into their initial forms The enzymatic reduction of the dyes was studied and the kinetic constants determined and these were compared to the chemicallyreduced leuco form The enzyme responsible for the reduction showed homology to a NADHdependent reductase from B subtilis based on results from the MS/MS peptide mass mapping of the tryptically digested protein Additionally the reduction of Acid Blue 74 to its leuco form by reductase from B subtilis was confirmed using NADH regenerated by the oxidation of formic acid with formate dehydrogenase from Candida boidinii in the same solution
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