Enzymatic Treatment of Soils Contaminated with Phenol and Chlorophenols Using Soybean Seed Hulls

Abstract

This study presents the application of soybean seed hulls for the decontamination and/or detoxification of phenol and chlorophenol polluted soils. The effect of soil was examined on both catalytic activity of soybean seed hull peroxidase (SBP) and enzymatic transformation of phenol, 2-chlorophenol, and 2,4-dichlorophenol through the polymerization reaction. The sorption of the enzyme to soil organic matter was found to account for the loss of partial catalytic activity of soybean seed hulls in a soil slurry environment. The organic matter present in loamy soils, rather than other soluble soil constituents and soil micro-organisms, is a factor in SBP inhibition by soil and the corresponding decline in treatment efficiency of phenol and chlorophenols. Under improved conditions, however, soybean seed hulls demonstrated a satisfactory ability to catalyze the polymerization reaction. Over 96% of total phenols were removed using soybean seed hulls in a soil slurry bioreactor, which demonstrates a great potential in use of soybean seed hulls, a readily available and inexpensive source of SBP, for bioremediation of soils contaminated with phenolic compounds.