Valorization of Agro-Industrial Residues: Bioprocessing of Animal Fats to Reduce Their Acidity

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