Preparation and scanning electronic microscopy study of chitosan/polyvinyl (alcohol)-encapsulated crude urease extract.

Small capsules of a blended chitosan (QTS)-polyvinyl alcohol (PVA) mixture were prepared by the coacervation salting-out method using sodium sulphate (20%, w/v) as a coagulation solution followed by further treatment with a solution containing formic aldehyde (7%, w/v), sulphuric acid (20%, w/v) and sodium sulphate (25%, w/v). The morphology of the microcapsule wall was observed by scanning electron microscopy (SEM). The enzyme urease, as a crude extract, was encapsulated and the cross section of the loaded capsule was observed by SEM. The enzyme extract was fully immobilized and the enzymatic assay showed the presence of the enzyme in an active form with a shift in the pH maximum activity to a lower pH.