Adsorption and Degradation of Triphenyltin by Pseudomonas chlororaphis Immobilized in Alginate Beads

The adsorption and degradation of triphenyltin (TPT) by immobilized Pseudomonas chlororaphis CNR15 cells were investigated in a batch mode. The cells were entrapped in calcium alginate beads. Pyoverdine, which is a siderophore that participates in the degradation of TPT, was secreted from the immobilized P. chlororaphis CNR15 cells, and the concentration of pyoverdine increased for at least one month. The rate of TPT adsorption by the immobilized cells was significantly higher than that by the beads without cells, while the diphenyltin and monophenyltin produced by TPT degradation were largely soluble forms. The degradation activity was influenced by temperature and pH, and showed a maximum at 30°C and pH 8.8 These results suggest that the rate of TPT degradation by immobilized P. chlororaphis CNR15 depends on both the production and catalytic properties of pyoverdine.