Estimation of Cold Flow Performance and Oxidation Stability of Fatty Acid Ethyl Esters from Lipids Obtained from Escherichia coli

Abstract

The increase in energy demand and the decrease in oil reserves encourage the search for alternative energy resources. Biodiesel composed of fatty acid ethyl esters (FAEEs) is a promising alternative fuel. The more extended use of fatty acid methyl esters over FAEEs comes from the higher cost of ethanol compared to methanol. But the genetic development of microorganisms able to produce bioethanol in extensive quantities or directly FAEEs omitting the transesterification process can diminish the cost of FAEEs and make them competitive. This work shows how to predict the cold flow properties and the oxidation stability of biodiesel composed of FAEEs using only some milligrams of the sample. Prediction of the cloud point, the pour point, and the cold filter plugging point has been made with a multiple linear correlation using the total percentage of unsaturated compounds and the average length of the carbon chains and with a simple linear correlation using the crystallization onset temperature. The oxidation stability was correlated through a multiple linear regression using as parameters the total percentage of monounsaturated esters and the bis-allylic position equivalents index. All of the regression models show statistical significance and a high level of correlation.