biostudies-literatureDobrijevic DBiotechnology and Biological Sciences Research CouncilEngineering and Physical Sciences Research Council36608-36614https://www.ebi.ac.uk/biostudies/studies/S-EPMC9075147biostudies-literatureUnknown9(63)Ene-reductases (ERs) of the Old Yellow Enzyme family catalyse asymmetric reduction of activated alkenes providing chiral products. They have become an important method in the synthetic chemists' toolbox offering a sustainable alternative to metal-catalysed asymmetric reduction. Development of new biocatalytic alkene reduction routes, however needs easy access to novel biocatalysts. A sequence-based functional metagenomic approach was used to identify novel ERs from a drain metagenome. From the ten putative ER enzymes initially identified, eight exhibited activities towards widely accepted mono-cyclic substrates with several of the ERs giving high reaction yields and stereoselectivities. Two highly performing enzymes that displayed excellent co-solvent tolerance were used for the stereoselective reduction of sterically challenging bicyclic enones where the reactions proceeded in high yields, which is unprecedented to date with wild-type ERs. On a preparative enzymatic scale, reductions of Hajos-Parish, Wieland-Miescher derivatives and a tricyclic ketone proceeded with good to excellent yields.RSC advancesMetagenomic ene-reductases for the bioreduction of sterically challenging enones.PMC9075147BB/N01877X/1EP/K005030/1EP/P020410/1BB/L007444/1Dobrijevic DDawson NMendez-Sanchez DTappertzhofen NOrengo CABenhamou LAliev AEMoody TSBaud DHailes HCWard JMfalseMetagenomic ene-reductases for the bioreduction of sterically challenging enones.Ene-reductases (ERs) of the Old Yellow Enzyme family catalyse asymmetric reduction of activated alkenes providing chiral products. They have become an important method in the synthetic chemists' toolbox offering a sustainable alternative to metal-catalysed asymmetric reduction. Development of new biocatalytic alkene reduction routes, however needs easy access to novel biocatalysts. A sequence-based functional metagenomic approach was used to identify novel ERs from a drain metagenome. From the ten putative ER enzymes initially identified, eight exhibited activities towards widely accepted mono-cyclic substrates with several of the ERs giving high reaction yields and stereoselectivities. Two highly performing enzymes that displayed excellent co-solvent tolerance were used for the stereoselective reduction of sterically challenging bicyclic enones where the reactions proceeded in high yields, which is unprecedented to date with wild-type ERs. On a preparative enzymatic scale, reductions of Hajos-Parish, Wieland-Miescher derivatives and a tricyclic ketone proceeded with good to excellent yields.2019-01-01T00:00:00Z2019 Nov2026-05-30T20:53:20.417Z2025-04-04T10:02:09.076ZS-EPMC90751473553904410.1039/c9ra06088j