Immobilisation of enzymes involves trapping enzyme molecules within calcium alginate beads formed by dripping an enzyme-sodium alginate mixture into a calcium chloride solution. This prevents the enzyme from contaminating products and allows it to be recovered and reused through a column system. Immobilisation can also enhance enzyme stability and allow catalysis under unfavorable conditions. Glucose dipsticks and biosensors use the enzyme glucose oxidase to catalyze a reaction that produces a detectable product, such as hydrogen peroxide or a change in oxygen concentration, signaling the presence of glucose.