An integrated simulation approach will be developed and applied to model biochemical and biophysical properties of enzymes in aqueous and non-aqueous solvents: solubility and enzymatic function. We will tackle three major challenges: (i) Modelling of the thermodynamics of complex mixtures of substrates, products, additives, and solvents. (ii) Modelling of substrate binding to the enzyme, identification of bottlenecks and binding sites, and design of improved enzyme variants. (iii) Bridging the scale between microscopic (molecular) modelling and macroscopic kinetic models to interpret experimental data. The goal of the project is to establish a holistic modelling strategy, which enables the design of biocatalytic systems from first principles.