Fatty acid methyl esters (FAME) are a type of fatty acid ester that are derived by transesterification of fats with methanol. The molecules in biodiesel are primarily FAMEs, usually obtained from vegetable oils by transesterification. They are used to produce detergents and biodiesel. FAMES are typically produced by an alkali-catalyzed reaction between fats and methanol in the presence of base such as sodium hydroxide or sodium methoxide.