Enzymatic esterification of pre-treated and untreated acid oil soapstock

• Published in: WASTES - Solutions, Treatments and Opportunities II pp. 241 - 244
• Main Authors: Borges, J., Alvim-Ferraz, C., Almeida, M.F., Dias, J.M., Budžaki, S.
• Format: Book Chapter
• Language: English
• Published: United Kingdom CRC Press 2018; Taylor & Francis Group
• Edition: 4
• Subjects: Thermomyces Lanuginosus Lipase; Removal Assays; Esterification Reaction; Pre-treated Oil; Enzymatic Esterification; Untreated Oil; Thermomyces Lanuginosus; Fatty Acid Methyl Ester; MSWI Fly Ash; X-ray Fluorescence Spectrometry; Dm −3; Methyl Ester Content; Biodiesel Production; Enzyme Dilution; Vegetable Oil Refining; Acidity Reduction; RDF; FFA Esterification; SEM; FFA Reduction; Acid Oil; Fatty Acid Methyl Ester Content; Moisture Content; Raw Vegetable Oils
• ISBN: 113819669X; 9781138196698
• DOI: 10.1201/9781315206172-37

The soapstock oil presents high Free Fatty Acid (FFA) content, being potentially a sustainable alternative feedstock for biodiesel production. In the present work, enzymatic esterification using a suspension of Thermomyces lanuginosus lipase was conducted on pre-treated and untreated acid oil from soapstock derived from the refining of vegetable oil mixtures. The enzyme suspension was prepared by mixing it with a 1 M phosphate buffer (1:10 V/V, enzyme:buffer). Esterification was conducted in an orbital shaking incubator at 40.0°C using a molar ratio of acid to methanol of 1:3, during 24 h at 200 rpm; monitoring was performed at 0, 7 and 24 h. Around 80% FFA reduction was obtained using raw and pre-treated oil, showing that the use of suspended enzyme avoids the need for pretreatment. Fatty Acid Methyl Ester content was determined, indicating that both esterification and transesterification reactions occurred. The soapstock oil presents high Free Fatty Acid (FFA) content, being potentially a sustainable alternative feedstock for biodiesel production. In this chapter, enzymatic esterification using a suspension of Thermomyces lanuginosus lipase was conducted on pre-treated and untreated acid oil from soapstock derived from the refining of vegetable oil mixtures. The use of a Thermomyces lanuginosus lipase suspension, by enzyme dilution with a phosphate buffer solution was effective to avoid enzyme inhibition by mineral acidity of raw soap-stock oil. Under the studied conditions it was possible to achieve the same acidity reduction, of 80 wt." after enzymatic esterification using both the pre-treated and untreated oil. Using the pre-treated oil, the reaction progressed faster; however, taking into account pre-treatment costs and expected loss of product, the use of suspended enzyme as described appears to be promising towards avoiding enzyme inactivation and effective esterification of free fatty acids.