Valorization of agro‐industrial residues: Bioprocessing of animal fats to reduce their acidity

• Published in: Sustainability
• Main Authors: António A. Martins, Teresa M. Mata, Nídia de Sá Caetano, Soraia Andrade, Daniela Correia, Elisabete Matos
• Other Authors: Faculdade de Engenharia
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Slaughter; Antarc*; Antarctica
• Online Access: https://hdl.handle.net/10216/137082; https://doi.org/10.3390/su131910837

Adding value to agro‐industrial residues is becoming increasingly important, satisfying needs to promote resources' use efficiency and a more sustainable and circular economy. This work performs a parametric and kinetic study of enzymatic esterification of lard and tallow with high acidity, obtained by the rendering of slaughter by‐products, allowing their use as a feed ingredient and increasing their market value. After an initial analysis of potential enzyme candidates, a Candida antarctica lipase B was selected as a biocatalyst for converting free fatty acids (FFA) to esters, using excess ethanol as the reagent. Results show that the fat acidity can be reduced by at least 67% in up to 3 h of reaction time at 45 °C, using the mass ratios of 3.25 ethanol/FFA and 0.0060 enzyme/fat. Kinetic modelling shows an irreversible second‐order rate law, function of FFA, and ethanol concentration better fitting the experimental results. Activation energy is 54.7 kJ/mol and pre-exponential factor is 4.6 × 106 L mol−1 min−1. (c) 2021 by the authors. Licensee MDPI, Basel, Switzerland.