MILP models for the synthesis of protein purification processes

Abstract

This chapter discusses the mixed-integer linear programming (MILP) models for the synthesis of protein purification processes. Formulations that are based on convex hull representations are proposed to calculate the minimum number of steps from a set of chromatographic techniques that must achieve a specified purity level and alternatively to maximize purity for a given number of steps. Models are tested in several examples and present time reductions of up to three orders of magnitude when compared to big-M models. The software GAMS 2.25 was used to implement the model and its solution method. The proposed models were solved with Optimization Subroutine Library (OSL). The models are solved for three different examples of increasing size. The chapter presents statistical data for the three examples and four MILP models. The models present a smaller number of binary variables, because these are defined simply for the selection of steps. Results are also compared to the ones obtained from Big-M representations.