BIODEGRADATION OF PHENOL BY IMMOBILIZED PROVIDENCIA RETTGERI

The cells of locally isolated, phenol-degrading Providencia rettgeri strain were immobilized by either entrapment within alginate beads or adsorption on silicate solid supports; celite R-634 and sintered glass rings (siran). Although the cells immobilized by adsorption on celite and siran showed high phenol degradation activity but phenol corrosion effect were observed on celite and siran particles as a release of fine powdery partieles to the degration medium. The immobilized cells degraded phenol by 3 times more than free cells in synthetic liquid medium containing phenol as sole carbon and energy source. The shaken cultures of calcium alginate immobilized P. rettgeri cells degraded and utilized phenol as carbon and energy source in synthetic liquid medium up to 5 g/L. The cells immobilized with 3% w/v alginate showed the highest rate of phenol degradation and utilization and the optimum phenol degradation and utilization was shown with an inoculum size either with beads seeded with 2.6 x 10 cells/ml or the degradation medium loaded with 15 g seeded aglinate beads per 50 ml synthetic liquid medium in shakn cultures at 30°C for an incubation period 6 days.