Biodegradation of 2,4-dinitrophenol with laccase immobilized on nano-porous silica beads

Many organic hazardous pollutants, including 2,4-dinitrophenol (2,4-dnp), which are water soluble, toxic, and noteasily biodegradable make concerns for environmental pollution worldwide. in the present study, degradation ofnitrophenols-contained effluents by using laccase immobilized on the nano-porous silica beads was evaluated.2,4-dnp was selected as the main constituent of industrial effluents containing nitrophenols. the performanceof the system was characterized as a function of ph, contact time, temperature, pollutant, and mediatorconcentrations. the laccase-silica beads were employed in a mixed-batch reactor to determine the degradationefficiency after 12 h of enzyme treatment. the obtained data showed that the immobilized laccase degraded morethan 90% of 2,4-dnp within 12 h treatment. the immobilization process improved the activity and sustainability oflaccase for degradation of the pollutant. temperatures more than 50°c reduced the enzyme activity to about 60%.however, ph and the mediator concentration could not affect the enzyme activity. the degradation kinetic wasin accordance with a michaelis–menten equation with vmax and km obtained as 0.25–0.38 ?moles/min and0.13–0.017 mm, respectively. the stability of the immobilized enzyme was maintained for more than 85% of itsinitial activity after 30 days. based on the results, it can be concluded that high resistibility and reusability ofimmobilized laccase on cpc-silica beads make it considerable choice for wastewater treatment.