The enzyme loading on the solid support was determined by quantifying the non-bound enzyme concentrations of CiVHPOHalo in the supernatants using the monochlorodimedon (MCD) Assay (for detailed information, see ESI Fig. ) after the immobilisation protocol. By measuring the decrease of MCD absorbance (290 nm) over time, enzyme concentrations could be calculated using a calibration slope. With this information, the amount of enzyme on the particles was determined. Usually, 7.47 -20.6 µg CiVHPOHalo was immobilised per 1 mg of chloroalkanemodified particle. CiVHPOHalo was also immobilised on the amine functionalised ProntoSIL particles by non-covalent interactions (up to 12.2 -18.8 µg of CiVHPOHalo was immobilised per 1 mg of amine particle).