Methods of producing carboxylic acids and/or alcohols

The invention relates to methods for producing carboxylic acids and/or alcohols by a fermentation process comprising: growing an immobilized microorganism capable of producing carboxylic acids and/or alcohols in an aqueous medium and in the presence of an organic medium, and recovering the carboxylic acids and/or alcohols from the organic medium; wherein a mesh is placed at an interface of the organic medium and the aqueous medium; and further wherein the organic medium comprises at least one organic solvent and at least one extractant chosen from tri-alkylphosphine oxides and tri-alkylamines.