The reduction of alkenes in starting material and reaction intermediates is an important transformation in the development of molecules for the agrochemical, fine chemical, and pharmaceutical industries. Reduction of alkenes can be achieved using heterogeneous catalysts and biocatalysts. For hydrogenation of alkene catalysts, palladium supported catalysts are commonly used, but platinum catalysts are useful to avoid the potential complications of double bond migration and cis–trans isomerization. 

As an alternative way to reduce the carbon-carbon double bond, ene reductase enzymes can be utilised. These biocatalysts are advantageous for substrates bearing multiple functional groups susceptible to reduction, where conventional metal catalysts can show poor chemoselectivity. In such cases, ene-reductases provide highly selective hydrogenation of th C=C bond while leaving other reducible moieities unchanged.  Enzymes can also simplify downstream processing, which is an advantage when the metal removal process is complex.