NOVELTY - Obtaining simultaneously several compositions comprising fatty acid alkyl esters, glycerol formal and bioester fatty acid glycerol formal ester, comprises e.g.: (a) reacting triglyceride, glycerol and dialkoxymethane in presence of acid homogeneous or heterogeneous catalyst, thus forming two layers, where upper layer comprises a mixture of fatty acid alkyl esters, fatty acid glycerol formal esters and excess of dialkoxymethane and alkyl alcohol and lower layer comprises a mixture of glycerol formal, excess glycerol, and homogeneous catalyst if an homogeneous catalyst has been used in reaction.    USE - The process is useful for obtaining simultaneously several compositions comprising fatty acid alkyl esters, glycerol formal and the bioester fatty acid glycerol formal ester (claimed) which are useful as biofuels e.g. as automotive fuel or heating oil, in automotive and industrial applications.    ADVANTAGE - The process: does not generate any by-products and water; can be integrated easily to current biodiesel production systems; and allows the conversion of a conventional biodiesel manufacturing plant in order to obtain fatty acid methyl ester and glycerol formal instead of fatty acid methyl ester and glycerol.    DETAILED DESCRIPTION - Process for obtaining simultaneously several compositions comprising fatty acid alkyl esters, glycerol formal and the bioester fatty acid glycerol formal ester, comprises: (a) reacting triglyceride, glycerol and dialkoxymethane in the presence of an acid homogeneous or heterogeneous catalyst, thus forming two layers, where the upper layer comprises a mixture of fatty acid alkyl esters, fatty acid glycerol formal esters and an excess of dialkoxymethane and alkyl alcohol and the lower layer comprises a mixture of glycerol formal, excess glycerol, and homogeneous catalyst if an homogeneous catalyst has been used in the reaction; (b1) separating the dialkoxymethane and the alkyl alcohol from the upper layer for obtaining a composition comprising fatty acid alkyl esters and fatty acid glycerol formal esters; (b2) separating the glycerol formal from unreacted glycerol and the homogeneous catalyst if an homogeneous catalyst has been used in step (a) from the lower layer for obtaining a composition comprising glycerol formal; (c) reacting the compounds from the upper layer obtained in (a) with a mixture of alkyl alcohol and acid catalyst for obtaining a composition comprising fatty acid alkyl esters and a composition comprising glycerol formal; and (d) carrying out a transesterification reaction between the composition obtained in step (b1) or the composition comprising fatty acid alkyl esters obtained in step (c) and the composition comprising glycerol formal obtained in step (c) in the presence of a transesterification homogeneous or heterogeneous catalyst to form a composition comprising fatty acid glycerol formal ester.