A dry porous macromolecular matrix comprising a cross-linked mixture of 69.9 to 86.6% by weight of an inert protein and 0.4 to 10.2% by weight of a lipase enzyme and a cross-linking agent, the amount of cross-linking agent being about 11.7% to 23% by weight. Also within the scope of the present invention is a process for preparing the dry porous macromolecular matrix. This process comprises reacting the lipase enzyme, the inert protein and the cross-linking agent with a buffer solution, freezing the resulting reaction mixture at a temperature ranging between -20°C and -195°C, allowing the frozen mixture to thaw to a temperature ranging from 4°C to 25°C, and rinsing and drying the resulting product at room temperature.