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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Bio-oils Research » Research » Publications at this Location » Publication #319259

Research Project: Vegetable Oil-Based Fuels, Additives and Coproducts

Location: Bio-oils Research

Title: Decolorization improves the fuel properties of algal biodiesel from Isochrysis sp.

item O'neil, Gregory - Western Washington University
item Knothe, Gerhard - Gary
item Williams, John - Western Washington University
item Burlow, Noah - Western Washington University
item Reddy, Christopher - Woods Hole Oceanographic Institute (WHOI)

Submitted to: Fuel
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2016
Publication Date: 3/23/2016
Publication URL:
Citation: O'Neil, G.W., Knothe, G., Williams, J.R., Burlow, N.P., Reddy, C.M. 2016. Decolorization improves the fuel properties of algal biodiesel from Isochrysis sp. Fuel. 179:229-234.

Interpretive Summary: Biodiesel is an alternative to petroleum-derived diesel fuel. While biodiesel fuel is usually produced from vegetable oils, such as soybean oil, or other feedstocks, such as animal fats and waste frying oils, in recent years, oils made from algae have been gaining interest as potential sources. The biodiesel derived from algal oils has been beset, however, with problems related to fuel properties. This work now describes a novel approach to improving the fuel properties of biodiesel from algal oils by bleaching the fuel. The bleaching process removes components from the biodiesel that negatively impact fuel properties. As a result, the bleached biodiesel fuel has improved cold flow and combustion properties as indicated by the higher cetane number, which is a measure of diesel fuel ignition. This approach may prove useful for improving the properties of other biodiesel fuels derived from algal oils.

Technical Abstract: Results from the comprehensive fuel testing according to the American Society for Testing and Materials International (ASTM) standards of an alkenone-free and decolorized biodiesel produced from the industrially grown marine microalgae Isochrysis sp. are presented. Fatty acid methyl ester (FAME) profiles of the non-decolorized and subsequently decolorized biodiesel fuels were nearly identical, yet the fuel properties were remarkably different. Significant positive impacts on the cetane number, kinematic viscosity, and lubricity were observed, indicating a potential deleterious effect of pigments like chlorophylls and pheophytins on these fuel properties. The decolorization process using montmorillonite K10 gave an average 90% mass recovery, and allowed for an otherwise unobtainable cloud point determination. Oxidative stability of the decolorized Isochrysis biodiesel remained well below the minimum prescribed in biodiesel standards due to elevated content of highly polyunsaturated fatty acids, however other values were in the range of those prescribed in the ASTM standards. Overall, decolorization improved the fuel properties of biodiesel from Isochrysis and may provide a path toward improved biodiesel fuels from other algal species.