الفهرس | Only 14 pages are availabe for public view |
Abstract One bacterial consortium 2K₂3 was isolated from a sewage sample and shown to be capable to degrade transform the tested analgesics (ketoprofen, paracetamol and aspirin) used in this study. K₃ consortium was molecularly identified to consist of 4 Gram negative bacteria. The isolated microalgal strain chlorella sp (A₁ ) was able to tolerate the tested drugs. The toxicity assays performed by both the microalgal toxicity (using the isolated chlorella) and brine shrimp (artemia) lethality assays showed that paracetamol was the least toxic drug followed by aspirin then ketoprofen. Assays, with both biological systems, showed that p- aminophenol (the 1st metabolite of paracetamol) was of higher toxicity than paracetamol. K consortium was able to degrade up to 16 mM (4 g.l⁻¹) of 2 ketoprofen within 120 h and 28 mM (5 g.l⁻¹) of aspirin within 48 h. The biodegradation of ketoprofen under dark conditions showed that there is a biodegradation pathway that was not reported before. All tested wastewater samples including K₂ consortium could transform paracetamol into a brown-colored intermediate that persisted till the end of the experiments (28 days). The HPLC analysis of paracetamol biodegradation experiment identified this intermediate to be p-aminophenol that was formed under either dark or continuous illumination conditions. Combination of K₂ and A₁ in a photobioreactor for bioremediation of simulated wastewater supplemented with a mixture of sub-lethal doses of the test analgesics was done. Initially at HRT (hydraulic retention time) of 3 days (phase A) there was some deterioration in the system accompanied with the appearance of the brown-colored p-aminophenol oxidation products |