The invention relates to at least one nucleotide sequence, derived from a nucleotide sequence encoding an acyltransferase polypeptide comprising at least one membrane-spanning region, encoding an improved active membrane independent acyltransferase polypeptide in which at least one amino acid residue of the membrane-spanning region has been deleted and/or substituted as compared to the original acyltransferase polypeptide, wherein the encoded active membrane independent acyltransferase polypeptide can produce fatty acid esters and/or fatty acid thioesters such as triacylglycerols, diacylglycerols, monoacylglycerols, phospholipids, glycolipids, waxesters, acylated carbohydrates, acylated amino acids, and lysolipids, e.g. lysophosphospholipid, lysolecithin. Thereby one single acyltransferase can be used for the production of a huge number of products. The invention also relates to means and methods for the production of such an improved active membrane independent acyltransferase and the use of such a membrane independent acyltransferase in industry.