Abstract: A simple, efficient method for immobilization of enzymes on siliceous supports is provided. In a preferred embodiment, a siliceous support having surface hydroxyl groups such as silica gel is contacted with a solution of a polyaldehyde cross-linking agent such as glutaraldehyde to produce a modified support containing bound cross-linking agent. After separation from the solution, the modified support is contacted with a solution containing an enzyme to bind the enzyme to free aldehyde functions of the cross-linking agent. Owing to properties peculiar to siliceous supports, the resulting immobilized enzyme is much more stable than enzymes immobilized on other supports. Consequently, much less enzyme is required. The immobilized enzymes generated via this process are ideally suited for continuous enzymatic production of commodity chemicals and pharmaceuticals such as L-DOPA, and for other enzyme-mediated industrial processes.