A new method of enhanced extraction genistein from pigeon pea [Cajanus cajan (L.) Millsp.] roots with the biotransformation of immobilized edible Aspergillus oryzae and Monacus anka, was investigated. It showed that immobilized Aspergillus oryzae and Monacus anka on sodium alginate effectively supported the highest genistein extraction yield by screening microorganism tests. After biotransformation process with immobilized Aspergillus oryzae and Monacus anka under 30 degrees C, pH 6.0, 2 days, liquid-solid ratio 12: 1 (mL/g), the extraction yield of genistein reached 1.877 mg/g, which was 2.65-fold to that of normal extraction yield. Moreover, IC50 values of the extracts measured by DPPH-radical scavenging test and beta-Carotene-linoleic acid bleaching test were 0.737 mg/mL and 0.173 mg/mL (control sample 1.117 mg/mL and 0.216 mg/mL), respectively. SOD (Super Oxygen Dehydrogenises) activity of the extracts treated with immobilized microorganism which was stronger than that of the untreated pigon pea roots (1.44 U/mg) at the concentration of protein (0.9375 mu g/mL) was 1.83 U/mg. The developed method could be an alternative method for the enhanced extraction of genistein from plants and could be potentially applied in the food industry (C) 2013 Elsevier Ltd. All rights reserved.