The application of a low purity soybean peroxidase (LP-SBP), obtained from wasted seed hulls, as catalyst for phenol polymerisation in aqueous solution in the presence of hydrogen peroxide is described. The polymers formed precipitate out from solution and may be readily separated by physico-chemical techniques. LP-SBP offers the advantage of reduced cost compared with horseradish peroxidase (HR-P). The SBP activity in fresh hulls was greater than in aged hulls and was preserved at -10degreesC. There was a linear correlation between initial phenol concentration (1, 2, 5 and 10 mmol dm(-3)) and the minimum dosage of LP-SBP required to precipitate 95% of the phenolic polymers. Polyethylene glycol (molecular weight, 6000) at 1000 mg dm(-3) did not extend LP-SBP lifetime. At all phenol concentrations tested, a retention time of about 100 min was sufficient to achieve yields of 95%.