Evaluation of Different Heating Systems for the Hydrolysis of Residual Frying Oil Catalyzed by Free and Immobilized Lipase

Abstract

Large quantities of residual cooking oil are being increasingly generated in various sectors, as it is often improperly disposed of and causes serious environmental problems. A commonly used alternative is the use of lipases in enzymatic hydrolysis, since it is rather attractive to several sectors, in addition to allowing the use of products generated thereof, such as: free fatty acids, diacylglycerols, monoacylglycerols and free glycerol, moreover, it is capable of operating in mild temperature and pressure conditions. Therefore, the present study aimed to evaluate alternatives for the hydrolysis of residual frying oil by evaluating the efficiency of different types of supports and heating systems using free and immobilized forms of lipase from Burkholderia cepacia (BCL) and Porcine pancreas (PPL) as biocatalyst. Polyhydroxybutyrate (PHB), niobium oxide (Nb₂O₅) and chitosan (CHIT) were evaluated as support for immobilizing BCL and PPL lipases, and superior results were found regarding the hydrolytic activity of immobilization derivatives using PHB and Nb₂O₅. Among the heating systems under evaluation, the highest percentage of residual oil hydrolysis was found using the ultrasound system for both free and immobilized lipases, reaching 57.91% hydrolysis for lipases immobilized on Nb₂O₅ and 61.11% hydrolysis for the derivative immobilized on PHB. The operational stability of both biocatalysts was evaluated using similar half-life time values for both. Thus, it was observed that the ultrasound system was efficient in improving lipase performance in the hydrolysis of free fatty acids, once this unconventional heating system is quite promising for accelerating such enzymatic reactions.

Keywords:
Residual cooking oil 1; Burkholderia cepacia lipase 2; Porcine pancreas lipase 3; Immobilization 4; Hydrolysis 5

HIGHLIGHTS

• Studying alternatives for the enzymatic hydrolysis of residual frying oil catalyzed by free and immobilized lipase.

• The use of polyhydroxybutyrate, niobium oxide and chitosan as support for immobilization of lipases.

• Efficiency assessment of the cycle of immobilized lipases in residual oil hydrolysis.