MICROBIOLOGICAL AND BIOCHEMICAL STUDIES ON THE PRODUCTION OF ISOFLAVONES

Abstract

 Pure colonies of twenty-three bacterial and fungal isolates were isolated from different Egyptian soil locations and were cultivated on media containing defatted soybean flour or cellobiose as a source of beta-glycosides and to test their capabilities to produce β-glucosidase.  All fungal isolates produced more extracellular β-glucosidases than those obtained by bacterial isolates during soybean flour fermentation.  All bacterial isolates showed positive cell-bound β-glucosidase activity.  Soybean flour fermented by the tested bacterial isolates resulted in a higher transformation of daidzin and genistin into daidzein and genistein, while that fermented by the tested fungal isolates could not perform the transformation except fungal isolates No. 5, 10 and 11 which had the capability to transfom only daidzin into daidzein.  Fermentation of defatted soybean flour by all bacterial and fungal isolates showed higher DPPH radical-scavenging activity in comparing to that of unfermented soybean flour.