Hydrolysis of olive oil was carried out with immobilized lipase with and without glutaraldehyde cross-linking. The reaction mixture which consisted of 30 ml of olive oil, 47.6 ml of я-hexane, 2.4 ml water, and 4 g immobilized lipase was incu­bated at 40°C, 200 rpm in a stirred tank reactor. Samples were withdrawn at specific time intervals and analyzed for fatty acids. The free fatty acids were estimated using NaOH by standard titimetry method. The results are depicted in Fig. 12.5f. The cross-linked lipase showed better hydrolytic activity as compared to the non-cross — linked enzyme. These results suggest that the proposed method of lipase immobili­zation has got profound potential in biofuel industry.