Hydrophobisation of starch is carried out in order to improve its mechanical and processing properties. Esterification is one of the most commonly used methods for this kind modification of starch. Lipase-catalysed synthesis of starch esters is rather environmentally friendly due to lack of by-products and very mild process conditions. Elimination or reduction of harmful and toxic solvents (DMSO, DMF) from the biocatalysed esterification of starch becomes possible due to an application of the new and easily recycled solvents - ionic liquids. In present studies, potato starch was esterified with an oleic acid, using immobilised lipases from Thermomyces lanuginosus as a catalyst and ionic liquid, 1-butyl-3-methylimidazolium chloride, as a gelatinisation medium. The degree of substitution (DS) of the obtained esters was determined by the volumetric method. The reaction product was subjected to Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and thermal analysis (TG). Moreover, in order to determine the usefulness of starch oleate in the packaging industry - the material was plasticized with glycerin (30% w/w) at the mixer and extruded as a film. The mechanical strength at static tension and tensile strength were examined. Additionally, water absorption and hydrophobicity were determined. Scanning electron microscope (SEM) was used to characterise the morphology of films. At the last part of study, the phytotoxicity analysis, including the impact on growth and vegetation of monocots and dicots plants, of starch esters as a powders and films was made.