Rates, Yields, and Economic Evaluation of Enzyme-Catalyzed Epoxidation of Soybean Oil and High Oleic Soybean Oil
Abstract
Enzyme-catalyzed epoxidation was utilized to produce epoxidized high oleic soybean oil (EHOSBO) with aqueous hydrogen peroxide without additional solvent or free fatty acids (FFA) at high yields as an environmentally friendly substitute to the current acid-catalyzed method. Epoxidized soybean oil (ESBO) is a commercially available, value-added product to plastic materials, with EHOSBO showing improved commercial characteristics compared to ESBO. Toluene, a toxic hydrocarbon, is a commonly reported solvent added to enzymatic epoxidations to improve enzyme activity and achieve higher yields. Additionally, in prior research FFA are added to the reaction to prevent hydrolysis of the triglyceride. These two steps decrease the sustainability, increase overall processing complexity and drive-up the cost of production. We showed that toluene is unnecessary for achieving high yields by adding hydrogen peroxide, the main cause for enzyme deactivation, at a slower rate and operating a lower reaction temperatures resulting in yields of 100% at 35 °C. Hydrolysis of the triglyceride was shown to occur to a similar level regardless of FFA addition. Gas chromatography analysis showed that oleic acid is fully epoxidized the fastest and at highest yields of the three main unsaturated fatty acids in soybean oil, supporting epoxidation for oil high in oleic acid. EHOSBO resulted in yields of 95% in the absence of toluene and without FFA added. Acid-catalyzed epoxidation resulted in significantly lower yields and a decrease in viscosity. Immobilized enzymes were utilized for design of a packed-bed reactor and an economic evaluation was conducted to determine the number of days needed to recycle the enzymes to be competitive with the current, commercial process.
Degree
M.S.A.B.E.
Advisors
Mosier, Purdue University.
Subject Area
Agriculture|Engineering|Agricultural engineering
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