ABSTRACT
The adsorption of cells to an organic or inorganic support material is achieved via the Van der Waals forces and ionic interactions. When cells are encapsulated in an immobilized cell system, the term “bioencapsulation” or “microencapsulation” is used; the latter is used when cells are immobilized in microcapsules. Biofilms are communities of microorganisms in which cells stick to each other and often adhere to a surface. These adherent cells are usually embedded within a self-produced matrix of extracellular polymeric substance. Cell entrapment can be achieved through in situ immobilization in the presence of the porous matrix or by allowing the cells to move into a preformed porous matrix. Gel entrapment has the disadvantage of limited mechanical stability. It has been frequently observed that the gel structure is easily destroyed by cell growth in the gel matrix and carbon dioxide production.
