Bi-objective optimisation of the enzymatic hydrolysis of porcine blood protein

Protein from porcine blood meal was hydrolysed with Alcalase to obtain a final revalorised product suitable, for example, to take part in the composition of an organic fertiliser. Three experimental factors of the reaction (pH, temperature and enzyme-substrate ratio) were optimised by means of a statistically designed experiment and response surface methodology. The goal of the optimisation problem was to maximise both the degree of hydrolysis and solubilisation of the substrate, obtaining a maximum degree of hydrolysis (28.89%) with pH 6.24, 54.2 degrees C and enzyme-substrate ratio of 10%. Regarding the content of suspended solids, its minimum value (30.29% related to the initial weight of blood meal) was attained at pH 7.5, 59.8 degrees C and enzyme-substrate ratio of 10%. The controversial effects of pH and temperature on the substrate solubilisation and the final degree of hydrolysis, suggested employing a multiobjective optimisation technique. A Pareto Front was generated in order to find a set of intermediate solutions which satisfied both objectives in an adequate degree. (c) 2011 Elsevier B.V. All rights reserved.