Application of lipase from the physic nut (Jatropha curcas L.) to a new hybrid (enzyme/chemical) hydroesterification process for biodiesel production

The aim of this study was to characterize a new plant enzyme (with high lipase activity) extracted from germinated physic nut seeds, and to apply this lipase to the production of biodiesel using a new process of enzyme/chemical hydroesterification. The lipase activity was detected only in the vegetable enzyme extract from germinated seeds (VEEG). Similar activities were obtained for substrates with different lengths of fatty-acid chains (111 ± 19 U/g for tributyrin (C4:0), 106 ± 49 U/g for tricaprylin (C8:0), and 96 ± 4 U/g for olive oil (C18:1)). The VEEG, obtained by a controlled processes of seed germination, was able to hydrolyze a wide range of biodiesel raw materials (vegetable oils, tallow, and biodiesel waste); of these, soy and physic nut oil showed especially high hydrolysis conversion (97% FFA). The biodiesel (fatty acid methyl esters) was produced by the hydrolysis of the physic nut oil using the VEEG, and subsequent esterification of the generated fatty acids with methanol by heterogeneous acid catalysis (niobic acid in pellets). The resulting biodiesel was of excellent quality, with the following properties: viscosity (5.5 mm2/s), ester content (97.1%), total glycerol (0.09 % w/w), max. methanol (0.05 % w/w), and CFPP (0 °C).