For immobilization experiments, a 25 ml aliquot of the cell culture in stationary phase was centrifuged at 5000 rpm for 10 min and the pellet was washed and resuspended in an equal volume of 0.2 M sodium phosphate buffer, pH 7.00. The resulting cell suspension was used for cell immobilization in silica matrices.
Pseudomonas sp. cells were immobilized into sol–gel silica matrices using citric acid in the sol–gel process