Chemoselective biohydrogenation of α,β- and α,β,γ,δ-unsaturated ketones by the marine-derived fungus Penicillium citrinum CBMAI 1186 in a biphasic system

To broaden the range of applicability of a reduction reaction mediated by the marine fungal strain Penicillium citrinum CBMAI 1186 to organic chemical processes, the ability of whole mycelia to grow in biphasic mixtures with organic solvents was tested with acetone, ethyl acetate, n-butanol, dichloromethane, n-hexane and toluene. n-Hexane was the least toxic solvent according to the amount of mycelial mass grown in an artificial sea water medium mixed with each solvent. Therefore, whole hyphae of P. citrinum CBMAI 1186 were used as biocatalysts in the chemoselective biotransformation of the carbon–carbon double bond in α,β-, di-α,β-, and mono-α,β,γ,δ-unsaturated ketones (3a, 3c–f) in a biphasic system of phosphate buffer and n-hexane (9:1). Only the di-α,β,γ,δ-unsaturated ketone (3b) was not biocatalyzed under these conditions. In general, there were good conversions of saturated ketones by the enoate reductase enzymes of P. citrinum CBMAI 1186.