Biotechnological synthesis of biodiesel fuel by interesterification of rapseed oil with methyl formate

Abstract

Due to the awareness of adverse effects of conventional fuels to environment and to frequent rise in crude oil’s price, the need for sustainable and environment friendly alternate source of energy has gained importance. Recently, options have been analysed to replace the triglyceride transesterification process, which is generally used in biodiesel production, by the process where raw glycerol is not generated, whereas triacylglycerides obtained instead glycerol can be directly used as fuel for a diesel engine in a mixture with fatty acid esters. In the present work, interesterification of rapeseed oil to biodiesel was carried out with methyl formate and using lipase as catalyst. Process scheme is shown in figure 1. First, the most effective biocatalyst suitable for the process was selected. 14 different lipases were studied. The samples obtained after the synthesis were analysed by the thinlayer and gas chromatography. Process experiments were performed using a methyl formate to oil molar ratio of 6 to 40, a lipase amount of 5 to 17 % (mass of oil), and synthesis duration of 3 to 48 h. The highest yield of fatty acid methyl esters (FAME) was obtained using Lipozyme RM IM as catalyst and its optimal amount was 13 %. Optimal temperature was found to be 20 °C and duration of interesterification 42 h. Optimal molar ratio of oil and methyl formate was determined 1:32. Under obtained conditions transesterifications degree was 60.68 %.