Profonofos is one of the widely used organophosphorus pesticides of which its contamination is plentiful in the agricultural area. The objective of this research was to study the degradation of profenofos pesticide. The cell entrapment technique was chosen to enhance the biodegradation for the future bioremediation application. In this study, a bacterial strain, Pseudomonas aeruginosa PF2, which was previously isolated for profenofos degradation was applied. Calcium alginate was selected as the cell entrapment matrix. This work focused on investigation of the optimum entrapped cell preparation. The cell (Pseudomonas aeruginosa PF2 at cell number of 10⁵ CFU/mL)-to-matrix (calcium alginate) ratios (by volume) of 1:5, 1:10  and 1:20 were tested. The experiment was performed by shaking the batch reactors for 150 rpm with the initial profenofos concentration of 20 mg/L under room temperature for 7 days.  The results showed that the calcium alginate-entrapped cells successfully removed profenofos (approximately 73-81%). The degradation followed the first order kinetics with the profenofos degradation rates of 0.35-0.67 1/d. The cell-to-matrix ratio of 1:20 performed the best. Higher ratio (1:5 and 1:10) may cause to high cell density inside the matrices resulting in lower profenofos degradation efficiency.

Keywords: calcium alginate, cell entrapment, cell-to-matrix ratio, profenofos