| Summary: | Jojoba oil, which is a wax ester mixture, is used as emmollient for skin protecting products and shompoos in the cosmetic industries; as additives for the food industries; and as lubricants for highprecision machinery. Oleyl oleate, which is an esterification product of oleic acid and oleyl alcohol, is a synthetic analogue of jojoba oil. In this study, oleyl oleate was produced by immobilized lipases in both atmospheric and supercritical C02 condition. Used enzymes in this study were Lipozyme RM IM (Mucor miehei, immobilized on anionic resin) and Novozym 435 (Candida antarctica, immobilized on acrylic resin) In the first step of the study, the method was developed for the determination of oleyl alcohol and oleyl oleate concentrations by GC and oleic acid concentration determined by titration was verified by GC. In the second step of the study, within atmospheric conditions, in the temperature and mixing rate controlled batch reactors, using solvent-free media, the effects of acid/alcohol molar ratio (1/7.5-6.65/1), amount of enzyme (2%-10 w/vt substrate mixture), temperature (30-60 "Q, mixing rate (100-250 rpm) and reaction time on the production of oleyl oleate with both enzymes are investigated. It is sufficient that ratio of enzyme/subtrate for each enzyme is 5 %; initial reaction rate, oleyl oleate concentration and yield have decresed under the values of acid/alcohol molar ratio of 1.33/1, and obtained maximum ester concentration is 31.5 mmol ester / g enzyme (with the conversion of 87%). Initial reaction rate has increased with temperature, mixing rate for Lipozyme RM IM 150 rpm, for Novozym 435 200rpm is sufficient The yield has increased from 87% to 97% by removing the water from media. Because of the initial reaction rate are higher that obtained with Novozym 435, this enzyme is used in the forward part of study. The effects of acid/alcohol molar ratio (0.67-2.00), amount of the enzyme (2%-10 w/w substrate mixture), reaction temperature (40-60 °C), reaction tüne (30-90 min) on the production of oleyl ...
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