NOVELTY - Preparing short-chain alkyl esters of fatty acids in solvent-free system comprises: (i) providing a fatty acid source; (ii) stepwise adding a short-chain free alcohol (preferably methanol) to the fatty acid source in the presence of a lipase preparation; and (iii) allowing the reaction to proceed under suitable conditions until the fatty acid source is converted to fatty acid methyl esters (FAME), where: the lipase preparation comprises at least two lipases that are separately or jointly immobilized on a suitable support; and at least one of the lipases is sn-1,3 positional specific.    USE - The method is useful for preparing short-chain fatty acid alkyl esters, which are fatty acid methyl esters (biodiesel). The immobilized lipase mixture is useful for the preparation of biodiesel (all claimed).    ADVANTAGE - The method provides a one-step or multi-step enzyme reactor configuration for obtaining the desired product, namely, fatty acid alkyl esters at near to complete conversions during reasonable reaction time, typically below 5 hours. The process yields fatty acid alkyl esters of content higher than 98% and a by-product, namely glycerol, of high quality. The two lipases present in the lipase preparation show a synergistic effect in their transesterification activity to obtain the final product. The method provides highly active, stable, and immobilized lipases for the synthesis of fatty acids alkyl esters, especially fatty acid methyl esters. The enzyme preparation possesses high tolerance towards short-chain alcohols and short-chain fatty acids, especially methanol, ethanol and acetic acid respectively, and other polyols such as glycerol, as well as other inhibiting factors typically present in oils and fats, in particularly of inedible grade. The prepared multi-enzyme immobilized preparation is recyclable with insignificant activity losses after reuse in more than 100 cycles.    DETAILED DESCRIPTION - Preparation of short-chain alkyl esters of fatty acids in solvent-free system comprises: (i) providing a fatty acid source; (ii) stepwise adding a short-chain free alcohol (preferably methanol or any other alcohol donor) to the fatty acid source in the presence of a lipase preparation; and (iii) allowing the reaction to proceed under suitable conditions until the fatty acid source (triglycerides) is converted to fatty acid methyl esters (FAME), where: the lipase preparation comprises at least two lipases that are separately or jointly immobilized on a suitable support; 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. An INDEPENDENT CLAIM is included for a process for the preparation of a mixture of lipases immobilized on an insoluble support (where the mixture comprises a lipase derived from Candida antarctica B and at least one lipase derived from Pseudomonas sp., Alcaligenes sp., Burkholderia sp., and Thermomyces lanuginosa) comprising: (a) contacting a buffer solution containing the lipase derived from C. antarctica B and at least one lipase derived from Pseudomonas sp., Alcaligenes sp., Burkholderia sp., and T. lanuginosa with a polymeric matrix, preferably an ion exchange resin or an adsorbent in the presence of a hydrophobic organic solvent, which is added to the immobilization medium at a ratio of 1:10-10:1 buffer:organic solvent, respectively; (b) mixing the system obtained in step (a) for at least 4 hours at room temperature; (c) filtering off of the immobilized lipase mixture; and (d) drying it to a water content of less than 5%.