Treatment of 2,4-dichlorophenol using soybean peroxidase.

Abstract

In the presence of hydrogen peroxide (H2O2), soybean peroxidase (SBP) extracted from the soybean seed coat catalyzes the polymerization of various chlorinated phenols from wastewater. The resulting polymer precipitates from solution and can be removed through a simple sedimentation or filtration process. To date, the majority of the research has focused on horseradish peroxidase (HRP) as the enzyme source. Recently, researchers have discovered that SBP is thermally more stable and can work in a different pH range than HRP. Since the soybean seedcoat is a waste product of the soybean industry, developing a value-added process to utilize the waste would be economical. Several limitations need to be resolved prior to this enzymatic process becoming a legitimate treatment. For instance, peroxidase enzyme (PE) inactivation is a primary concern in trying to make the process more viable. Researchers have postulated that the PE is inactivated by entrapment into the forming polymers. To prevent such occurrences, high molecular weight substance such as gelatin and polyethylene glycol (PEG) have been added to solution. PEG 8000 provides a significant increase in protection compared to PEG 3350, a standard additive used for HRP. To date, researchers studying SBP as an alternative to HRP have focused mostly on the treatment of phenol. The effectiveness of SBP to treat chlorinated phenols is presented in this research. Some of the parameters studied include the effects and interactions of temperature, reaction time, pH, SBP concentration, PEG molecular weight, PEG concentration, type of substrate, substrate concentration, mode of substrate addition, mode of SBP addition and mode of H2O 2 addition. SBP was found to be a suitable alternative to HRP offer similar results and in some cases, improved the results.