Phenols removal by immobilized horseradish peroxidase.
Application of immobilized horseradish peroxidase (HRP) in porous calcium alginate (ca-alginate) for the purpose of phenol removal is reported. The optimal conditions for immobilization of HRP in ca-alginate were identified. Gelation (encapsulation) was optimized at 1.0% (w/v) sodium alginate in the presence of 5.5% (w/v) of calcium chloride. Upon immobilization, pH profile of enzyme activity changes as it shows higher value at basic and acidic solution. Increasing initial phenol concentration results in a decrease in % conversion. The highest conversion belongs to phenol concentration of 2mM. Investigation into time course of phenol removal for both encapsulated and free enzymes showed that encapsulated enzyme had lower efficiency in comparison with the same concentration of free enzyme; however the capsules were reusable up to four cycles without any changes in their retention activity. Increasing enzyme concentration from 0.15 to 0.8 units/g alginate results in gradual increase in phenol removal. The ratio of hydrogen peroxide/phenol at which highest phenol removal obtained is found to be dependent on initial phenol concentration and in the solution of 2 and 8mM phenol it was 1.15 and 0.94 respectively.
Alemzadeh
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I
Chemical and Petroleum Engineering Department, Sharif University of Technology, P.O. Box 11365-9465, Tehran, Iran. alemzadeh@sharif.edu
Nejati
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S
D000464:Alginates; D002122:Calcium Chloride; D004800:Enzymes, Immobilized / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010636:Phenols / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D000464:Alginates; D004800:Enzymes, Immobilized; D010636:Phenols; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; D002122:Calcium Chloride