Assessment of Genistein and Daidzein Production By Some Local Fungal and Bacterial Isolates

Abstract

T WENTY-THREE different bacterial and fungal isolates were grown and screened for their capability to transform soy glycosides to their aglycone forms with higher titer of antioxidant activity compared to unfermented soy flour. Most of the bacterial isolates showed higher amounts of daidzein than of genistein, which are the aglycone products of daidzin and genistin. After fermentation of soybean flour using bacterial and fungal isolates, the content of isoflavone aglycones varied from 0.0 to 431.89 µg/g compared to unfermented autoclaved soybean flour. Extracellular β-glucosidase activity was ranged from 1.22 to 11.56 mU/mL and 0.3-534.3 U/mL for bacterial and fungal isolates, respectively, while, bacterial cell-bound β-glucosidase ranged from 44.72 to 128.89 mU/mL. Most of the bacterial isolates more efficiently transformed daidzin and genistin into the aglycones than fungal isolates. Among the tested bacterial isolates, the most potent one was selected, characterized according to the morphological and 16S rDNA sequence analysis and identified as Bacillus licheniformis NRC24.

Medium Optimization for Isoflavone Aglycones Production From Fermented Defatted Soybean Flour by Display of Β-Glucosidase From Bacillus Licheniformis Nrc24 and Evaluation of Their Antiviral and Antitumor Activities

“…paracasei and B. longum was 37°C (Rodríguez de Olmos et al, 2015). The activity of βglucosidase produced by lactic acid bacteria (LAB) was defined mainly in the cellfree extract via cell-bound β-glucosidase activity and was not detected in culture supernatant (El-shazly et al, 2017).Therefore, the cell-bound β-glucosidase activity will be considered as a toll for the biotransformation of soy glucosides.…”

“…Bacillus licheniformis NRC24 was isolated from Egyptian soil (El-Shazly et al, 2017). The strain was stored in 20% (v/v) glycerol at -80°C.…”