Treatment of Triclosan Through Enhanced Microbial Biodegradation

Ghafouri, Mahsa | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55889 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Yaghmaei, Soheila; Ghobadi Nejad, Zahra
  7. Abstract:
  8. Triclosan is widely used as an antibacterial agent in personal health care products, especially in recent years with the spread of the Coronavirus. This substance is one of the emerging contaminants, and due to its stable and toxic nature, this material cannot be destroyed in the process of biological wastewater treatment. In this research, a new bacterial strain was isolated and purified from industrial wastewater for the biological removal of triclosan. Based on 16S rRNA sequencing, it was found that the isolated strain belongs to the Enterobacter cloacae family and can grow in high concentrations of triclosan. It was observed that naphthalene dioxygenase and laccase enzymes are active during the process of triclosan degradation by the isolated strain. Biodegradation experiments to optimize parameters of temperature (20-35 degrees Celsius), pH (5-9), triclosan initial concentration (2-6.5 ppm), and removal time (6-10 days) using the response surface method. (RSM) was performed. The results showed that the most optimal percentage of triclosan removal (98%) for this strain is obtained at 32 degrees Celsius, pH 7, concentration 5 ppm, and within 9 days and 12 hours. The results showed a very significant correlation between experimental and predicted values with a coefficient of determination of 0.98. Also, the analysis of the results by gas chromatography-mass spectrometry led to the identification of 5 intermediate products and the introduction of a new degradation pathway of triclosan by the strain
  9. Keywords:
  10. Optimization ; Triclosane ; Biological Removal ; Separation ; Purification ; Naphthalene Dioxygenase Enzyme ; Laccas Enzyme ; Biological Degradation

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