Process optimization and modeling of trichlorophenol degradation by Phanerochaete chrysosporium

Area of Science:

• Environmental microbiology
• Bioremediation of chlorinated phenols
• White rot fungi biotechnology

Background:

• Chlorinated phenols, such as 2,4,6-trichlorophenol and 2,4,5-trichlorophenol, are persistent environmental pollutants.
• Phanerochaete chrysosporium is a lignin-degrading white rot fungus with known potential for xenobiotic degradation.

Purpose of the Study:

• To investigate and optimize the biodegradation of 2,4,6-trichlorophenol and 2,4,5-trichlorophenol using Phanerochaete chrysosporium.
• To compare degradation efficiency between suspended and immobilized fungal systems.
• To develop a mathematical model for the biodegradation process.

Main Methods:

• Comparative study using batch and continuous reactor systems (shake flasks vs. packed-bed reactors).
• Immobilization of Phanerochaete chrysosporium in packed-bed reactors.
• Investigation of key parameters: carbon/nitrogen sources, pH, and fluid shear stress.
• Development and validation of a two-step sequential reaction mathematical model including enzyme deactivation.

Main Results:

• Immobilized Phanerochaete chrysosporium in packed-bed reactors demonstrated degradation rates two orders of magnitude higher than suspended cells in shake flasks.
• Biodegradation rates were significantly influenced by nutrient concentrations, pH, and shear stress.
• Optimal ranges for these parameters were determined to maximize degradation efficiency.
• The developed mathematical model accurately described the experimental data, accounting for sequential reactions and enzyme deactivation.

Conclusions:

• Immobilization of Phanerochaete chrysosporium significantly enhances trichlorophenol biodegradation efficiency.
• Reactor design and operational parameters critically affect bioremediation performance.
• A robust mathematical model aids in understanding and predicting the complex biodegradation kinetics.