Investigation of Biophotocatalytic Conversion of Used Cooking Oil into Olefins

The possibility of biophotocatalytic conversion of used cooking oil was investigated. The targeted transformation of used cooking oil into the desired olefin products was demonstrated using a modification of a previously published protocol, which resulted in the yield of the desired olefin products of 36.1% (±6.1%). Subsequently, the possibility to replace the originally used solvent dichloromethane with two more environmentally benign solvents 2-methyltetrahydrofuran and tert-butyl methyl ether was investigated, and tert-butyl methyl ether was identified as a potential replacement solvent. The yield of the desired olefin products for the reactions conducted using tert-butyl methyl ether was 41.2% (±2.6%). Furthermore, the potential of recycling the catalytic system was investigated both in dichloromethane and in tert-butyl methyl ether. Recycling was possible only when tert-butyl methyl ether was used, as loss of enzyme activity after the initial run of the reaction was observed in dichloromethane. Potential for recycling of the entire catalytic system was demonstrated as well. Scaled up experiments exhibited reduced reaction yield, which was ascribed to the need for extension of reaction time. The feasibility of the reaction was also demonstrated with waste pork fat. Finally, GC-MS analysis indicates that the product makeup corresponds to the fatty acid composition of the starting materials.