Polyhedral foams offer large gas-liquid interfacial area associated with a small amount of liquid. Therefore, if a solute adsorbs preferentially at the interface, the concentration of the solute in the foam will be greater than in the solution from which the foam has been generated. This effect provides a simple method of concentrating materials which have a tendency to adsorb on the gas-liquid interface. This is particularly relevant to biomaterials like whole cells, proteins, enzymes etc., which are surface active and are present in low concentrations in the broth. Foam separation has therefore attracted considerable attention, and several reports exist in literature on concentrating cells, proteins and enzymes using foams. Foam separation is based on the difference in surface activity of the components to be separated. A surface active molecule consists of a lyophobic and a lyophilic group. (As water is commonly used as a solvent, the lyophilic and lyophobic groups are called hydrophilic and hydrophobic groups, respectively). When dissolved in a solvent, the presence of lyophobic groups in the interior of the solvent distorts the solvent liquid structure, thereby increasing the free energy of the system.