The invention relates to a method for oxidizing a fatty acid or an ester thereof of formula (I) H3C —(CH2)n-COOR, wherein R is selected from the group that comprises H, methyl, ethyl, propyl, and butyl, wherein n is 0 to 30, preferably 6 to 24, comprising the step of oxidizing the fatty acid or the ester thereof by contacting the fatty acid or the ester thereof with a cytochrome P450 monooxygenase of the CYP153 family in the presence of molecular oxygen and NAD(P)H and a whole-cell catalyst that expresses a recombinant cytochrome P450 monooxygenase of the CYP153 family, a recombinant alcohol dehydrogenase, a recombinant transaminase, and optionally one or more than one recombinant enzyme from the group comprising alanine dehydrogenase, ferredoxin, and ferredoxin reductase, and the use of said whole-cell catalyst to oxidize a fatty acid or an ester thereof.