A method of producing linear fatty acids comprising 7 to 28 carbon atoms or esters thereof, from ethanol and/or a linear alkanoic acid comprising 2 to 5 carbon atoms, the method comprising (a) contacting ethanol and/or the linear alkanoic acid comprising 2 to 5 carbon atoms or any salts thereof with at least one microorganism capable of carrying out two-carbon chain elongation to produce as an intermediate a linear alkanoic acid comprising 4 to 7 carbon atoms and/or a salt thereof and/or an ester thereof; (b) extracting the intermediate, its salt and/or ester thereof from (a) using at least one extractant, wherein the extractant comprises at least one alkyl-phosphine oxide and optionally at least one alkane comprising at least 12 carbon atoms; or at least one trialkylamine and at least one alkane comprising at least 12 carbon atoms; (c) contacting the extracted intermediate linear alkanoic acid comprising 4 to 7 carbon atoms, its salt and/or ester thereof from (b) with at least one ketonization catalyst and optionally a further alkanoic acid comprising 2 to 22 carbon atoms under suitable reaction conditions for chemical ketonization of the intermediate linear alkanoic acid comprising 4 to 7 carbon atoms, its salt and/or ester thereof to a linear alkanone comprising 7 to 28 carbon atoms; (d) contacting the linear alkanone comprising 7 to 28 carbon atoms from step (c) with at least one hydrogenation metal catalyst for catalytic hydrogenation of the linear alkanone comprising 7 to 28 carbon atoms to a corresponding secondary linear alkanol comprising 7 to 28 carbon atoms; (e) dehydration of the secondary linear alkanol comprising 7 to 28 carbon atoms in the presence of an acidic heterogeneous catalyst to form a corresponding linear alkene comprising 7 to 28 carbon atoms; (f) hydroxy or alkoxy carbonylation of the linear alkene comprising 7 to 28 carbon atoms to a linear fatty acid comprising 7 to 28 carbon atoms or an ester thereof in the presence of carbon monoxide, of an acid and of a catalyst comprising a transition metal. (a) contacting ethanol and/or the linear alkanoic acid comprising 2 to 5 carbon atoms or any salts thereof with at least one microorganism capable of carrying out two-carbon chain elongation to produce as an intermediate a linear alkanoic acid comprising 4 to 7 carbon atoms and/or a salt thereof and/or an ester thereof; (b) extracting the intermediate, its salt and/or ester thereof from (a) using at least one extractant, wherein the extractant comprises at least one alkyl-phosphine oxide and optionally at least one alkane comprising at least 12 carbon atoms; or at least one trialkylamine and at least one alkane comprising at least 12 carbon atoms; (c) contacting the extracted intermediate linear alkanoic acid comprising 4 to 7 carbon atoms, its salt and/or ester thereof from (b) with at least one ketonization catalyst and optionally a further alkanoic acid comprising 2 to 22 carbon atoms under suitable reaction conditions for chemical ketonization of the intermediate linear alkanoic acid comprising 4 to 7 carbon atoms, its salt and/or ester thereof to a linear alkanone comprising 7 to 28 carbon atoms; (d) contacting the linear alkanone comprising 7 to 28 carbon atoms from step (c) with at least one hydrogenation metal catalyst for catalytic hydrogenation of the linear alkanone comprising 7 to 28 carbon atoms to a corresponding secondary linear alkanol comprising 7 to 28 carbon atoms; (e) dehydration of the secondary linear alkanol comprising 7 to 28 carbon atoms in the presence of an acidic heterogeneous catalyst to form a corresponding linear alkene comprising 7 to 28 carbon atoms; (f) hydroxy or alkoxy carbonylation of the linear alkene comprising 7 to 28 carbon atoms to a linear fatty acid comprising 7 to 28 carbon atoms or an ester thereof in the presence of carbon monoxide, of an acid and of a catalyst comprising a transition metal. <EOS>