Immobilized enzymatic activity in the Venice lagoon sediment

Three insoluble enzymes (cellulase, phosphatase and urease) were found in the sediment phase of the Venice lagoon within an area of shallow water, the Palude della Rosa. Several washing treatments were performed to evaluate the binding forces between the enzymes and the solid phase. Urease was strongly bound and unaffected by all washing procedures tested, whereas phosphatase and part of the cellulase could be removed by phosphate anions. Cellulase activity was also solubilized by a non-ionic detergent. These immobilized enzymes showed marked heat stability and an increased resistance to environmental changes. They were probably of bacterial origin and could be advantageous for the removal of specific substances from water. They could be useful as diagnostic factors of the ecosystem, since their presence is related to the waste products and their lifespan is prolonged by their insolubilization.