Geotrichum candidum acetophenone reductase immobilization on reduced graphene oxide: A promising biocatalyst for green asymmetric reduction of ketones

Highly functional carbon-based materials, such as graphene family nanomaterials (GFNs) like graphene oxide (GO) and reduced graphene oxide (rGO), have been synthesized through the years. In this research, GO and rGO were used as support to immobilize a novel alcohol dehydrogenase (ADH), acetophenone reductase from Geotrichum candidum (GcAPRD), via physical adsorption. The synthesized GO-GcAPRD and rGO-GcAPRD allowed GcAPRD recycling. Moreover, rGO-GcAPRD succeeded in reduction of a wide range of ketones to their corresponding (S)-alcohols with excellent enantioselectivity, including a 'difficult to resolve' aliphatic ketone, 3-hexanone, to achieve 99% yield and > 99% ee (S). We also synthesized a drug intermediate such as (S)−1-(3′,4′-dichlorophenyl)ethanol with 80% isolated yield and > 99% ee. To the best of our knowledge, this is the first time to present the versatility of immobilized ADH on the GFNs via direct and simple physical adsorption as a promising biocatalyst for asymmetric synthesis.