Utilization of Waste Glycerol from Biodiesel Process as a Substrate for Mono-, Di-, and Triacylglycerol Production

Abstract

Glycerol (or glycerin) is a major by-product in the biodiesel process. Ten percent of crude glycerol are created for every 100 pounds of biodiesel produced. As the utilization of biodiesel increasing, an excess of glycerol is being generated. However, the purify of waste glycerol is expensive, biodiesel producers must search alternative methods for its utilization. This paper demonstrate the feasibility of producing mono-, di- and triacylglycerol from waste glycerol. The acylglycerol was produced through glycerolysis reaction using commercial lipase from Candida sp. Effects of various reaction parameters were evaluated. The optimum conditions for acylglycerol production were a glycerol to fatty acid mole ratio of 6∶1, 100 mg of lipase with the reaction temperature and time at 40°C and 24 h, respectively. Analysis of acylglycerol by Thin Layer Chromatography (TLC) using petroleum ether : diethyl ether :methanol:acetic acid (90:7:2.5:0.5 v/v) as mobile phase found that mono-, di- and triacylglycerol were produced in high purity. Interestingly, the highest production of acylglycerol yeild from commercial lipase and crude lipase from pacific white shrimp's hepatopancreas were obtained at the same conditions. Attenuated Total Reflectance (ATR)-Fourier Transform Infrared Spectroscopy (FTIR) proved that the final product contains mono-, di- and triacylglycerol.