A process for the preparation of short-chain alkyl esters of fatty acids, preferably fatty acid methyl esters (biodiesel) in solvent-free system is disclosed. In particular, the process comprises (a) providing a fatty acid source, (b) stepwise adding a short-chain free alcohol, preferably methanol, or any other alcohol donor, to said fatty acid source in the presence of a lipase preparation and (c) allowing the reaction to proceed under suitable conditions, until said fatty acid source triglycerides are converted to fatty acid methyl esters (FAME). The lipase preparation comprises at least two lipases. The two lipases being separately or jointly immobilized on a suitable support and wherein at least one of the lipases has increased affinity for partial glycerides and at least one of the lipases is sn-1,3 positional specific.