Used cooking oil is a widely generated waste stream, both in the food industry and in households, but it is difficult to manage. At the same time, the large quantities of plastic waste generated worldwide pose a major environmental problem. Addressing both challenges by valorising used cooking oil to produce bioplastics is the focus of research carried out at the Centre for Cross disciplinary Research in Environmental Technologies (CRETUS) at the University of Santiago de Compostela (USC).
The doctoral thesis of researcher Carlota Ucha, supervised by CRETUS researchers Anuska Mosquera and Ángeles Val from the department of chemical engineering, studied the development and evaluation of an integrated bioprocess for valorising used cooking oil to produce PHAs (biobased and biodegradable polymers) through a selected bacterial culture.
European legislation adopted in 2018 established deadlines for the mandatory separate collection of used cooking oil and introduced strict requirements for companies involved in its treatment. In Spain, separate collection has been mandatory since 2024. This regulatory framework makes used cooking oil a suitable waste stream for valorisation, as its quality and origin are properly controlled.
Against this background, and with the aim of addressing two environmental challenges, the researcher worked with different biological reactors in which bacteria were fed with used cooking oil and synthesised PHAs. Different process configurations and operating conditions were studied, together with other stages of the production process, at both laboratory and pilot scale. The research demonstrates the potential to valorise a difficult-to-manage waste stream and give it a new function while contributing to reducing another type of waste: plastic.
The research was carried out at CRETUS, a CIGUS network centre co-funded by European funds, within the framework of the national Ecopolyver project (PID2020-112550RB-C21, funded by MICIU/AEI /10.13039/501100011033), in which the Institute of Water of the University of Granada participates as a partner.
