Fatty acid methyl esters (FAME) are a type of fatty acid ester than can be produced by an alkali-catalyzed reaction between fats or fatty acids and methanol. The molecules in biodiesel are primarily FAMEs, usually obtained from vegetable oils by transesterification.
Since every microorganism has its specific FAME profile (microbial fingerprinting), it can be used as a tool for microbial source tracking (MST). The types and proportions of fatty acids present in cytoplasm membrane and outer membrance (gram negative) lipids of cells are major phenotypic trains.
Clinical analysis can determine the lengths, bonds, rings and branches of the FAME. To perform this analysis, a bacterial culture is taken, and the fatty acids extracted and used to form methyl esters. The volatile derivatives are then introduced into a gas chromatagraph, and the patterns of the peaks help identify the organism. This is widely used in characterizing new species of bacteria, and is useful for identifying pathogenic strains.