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Artificial Electron Transfer Mediators Reactivity and Application for Soluble PQQ- Dependent Glucose Dehydrogenase Catalysed Reactions Research Soluble PQQ-dependent glucose dehydrogenase (PQQ-sGDH) exhibits high catalytic activity, insensitivity to atmospheric oxygen and broad sacharidic substrate specificity. Because of potential qualities, this enzyme can be applied in many fields including sacharidic biosensor creation and for useful compound synthesis during bioconversion reactions in bioreactors. Efficient PQQ-sGDH application and action requires effective electron acceptors that is why the purpose of this bachelor thesis was to investigate the reactivity and application of artificial electron transfer mediators for PQQ-sGDH enzyme catalyzed reactions. During this work four artificial electron transfer mediators were tested spectrophotometrically. It was found that the best PQQ-sGDH reoxidation processes are reached with AMB and MPD electron acceptors. Enzyme optimal reactivity pH with AMB is at 6,5 and with MPD is at pH 7,0. It was also shown that lactose oxidation rate inhibition effect with substrate lactose and product lactobionic acid can be considerably reduced when pH is increased from 7,0 to 8,0. During electrochemical research it was shown that the best electroenzimatic lactose bioconversion yield and biggest average PQQ-sGDH turnover number is reached when buffer solution pH is 8,0 and AMB is used as an electron acceptor, which is oxidised on a carbon fiber electrode of large surface area. |
