Lipase-Catalyzed Production of Biodiesel by Hydrolysis of Waste Cooking Oil Followed by Esterification of Free Fatty Acids

Author(s)

Vescovi, Vinicius ; Rojas, Mayerlenis Jimenez ; Baraldo, Jr., Anderson ; Botta, Daniel Carrero ; Montes Santana, Felipe Augusto ; Costa, Julia Piva ; Machado, Mariana Stefani ; Honda, Vitor Kasuyoshi ; Camargo Giordano, Raquel de Lima ; Tardioli, Paulo Waldir

• Document type: Journal article
• Source: JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY; v. 93, n. 12, p. 1615-1624, DEC 2016.
• Web of Science Citations: 8

Abstract

Biodiesel is conventionally produced by alkaline-catalyzed transesterification, which requires high-purity oils. However, low-quality oils can be used as feedstocks for the production of biodiesel by enzyme-catalyzed reactions. The use of enzymes has several advantages, such as the absence of saponification side reactions, production of high-purity glycerol co-product, and low-cost downstream processing. In this work, biodiesel was produced from lipase-catalyzed hydrolysis of waste cooking oil (WCO) followed by esterification of the hydrolyzed WCO (HWCO). The hydrolysis of acylglycerols was carried out at 30 A degrees C in salt-free water (WCO/water ratio of 1:4, v/v) and the esterification of HWCO was carried out at 40 A degrees C with ethanol in a solvent-free medium (HWCO/ethanol molar ratio of 1:7). The hydrolysis and esterification steps were carried out using immobilized Thermomyces lanuginosus lipase (TLL/WCO ratio of 1:5.6, w/w) and immobilized Candida antarctica lipase B (10 wt%, CALB/HWCO) as biocatalysts, respectively. The hydrolysis of acylglycerols was almost complete after 12 h (ca. 94 %), and in the esterification step, the conversion was around 90 % after 6 h. The purified biodiesel had 91.8 wt% of fatty acid ethyl esters, 0.53 wt% of acylglycerols, 0.003 wt% of free glycerol, viscosity of 4.59 cP, and acid value of 10.88 mg KOH/g. Reuse hydrolysis and esterification assays showed that the immobilized enzymes could be recycled five times in 10-h batches, under the conditions described above. TLL was greatly inactivated under the assay conditions, whereas CALB remained fully active. The results showed that WCO is a promising feedstock for use in the production of biodiesel. (AU)

• FAPESP's process: 11/23194-0 - Enzymatic synthesis of fatty esters using heating assisted by microwave
• Grantee: Paulo Waldir Tardioli
• Support Opportunities: Regular Research Grants