Optimization of Alcohol Dehydrogenase for Industrial Scale Oxidation of Lactols

Abstract

Alcohol dehydrogenases (ADH) are widely used to enantioselectively reduce ketones to chiral alcohols, but their application in industrial scale oxidations is rare. Reasons are the need for an NAD(P)+ cofactor regeneration system, often low performance in oxidative reactions and the limited substrate scope of ADHs. ADHA from Candida magnoliae DSMZ 70638 is identified to efficiently catalyze the regio‐selective hydroxy‐lactone oxidations to hydroxy‐lactones. Hydroxy‐lactones are common intermediates in industrial processes to cholesterol lowering (va)statin drugs. A biocatalytic aliphatic hydroxy‐lactone oxidation process is developed using pure oxygen as oxidant reaching volumetric productivities of up to 12 g L−1 h−1, product concentrations of almost 50 g L−1 and 95% reaction yield. For co‐factor recycling a previously engineered, water‐forming NAD(P)H‐oxidase from Streptococcus mutans is used. The process is scaled up to industrial pilot plant scale and it could be demonstrated that ADH catalyzed oxidations can be developed to efficient and safe processes. However, the ADHA wild‐type enzyme is not productive enough in chlorolactol oxidation. Therefore, enzyme engineering and multi‐parameter screening is successfully applied to optimize the enzyme for the target reaction. The optimized ADHA variant shows a 17‐fold higher oxidative activity, a 26°C increased stability and is applied to develop an efficient chlorolactol oxidation process.

D-Allulose (D-Psicose) Biotransformation From Allitol by a Newly Found NAD(P)-Dependent Alcohol Dehydrogenase From Gluconobacter frateurii NBRC 3264 and the Enzyme Characterization

“…The ADHs catalyze interconversions between alcohols and aldehydes or ketones ( Maria-Solano et al, 2017 ; Zheng et al, 2017 ; Bartsch et al, 2020 ). For example, alcohol dehydrogenase from Pyrococcus furiosus can catalyze 2, 5-hexanedione to 2, 5-hexanediol ( Machielsen et al, 2008 ).…”

The beauty of biocatalysis: sustainable synthesis of ingredients in cosmetics

“…Other routes to lactones include the stereoselective reduction of unsaturated lactones to saturated lactones using ene reductases 341 or the oxidation of lactols to lactones with ADHs, which, with NAD(P)H oxidase as a cofactor recycling system, has been demonstrated on an industrial scale. 342…”

Biocatalytic oxidation of fatty alcohols into aldehydes for the flavors and fragrances industry

“…Recently, the use of an ADH/NOX coupled-system was demonstrated at pilot-scale for the oxidation of lactols (Bartsch et al, 2020), with the use of an engineered NOX enzyme (Petschacher et al, 2014). Alternatively, regeneration can be achieved by a substrate-coupled approach, where the ADH itself reoxidizes the co-factor by reducing a secondary substrate (see Figure 2).…”