Bioprocessing of pigeon pea roots by a novel endophytic fungus Penicillium rubens for the improvement of genistein yield using semi-solid-state fermentation with water

A novel endophytic fungus Penicillium rubens isolated from pigeon pea producing cellulase (0.73 ± 0.14 U/mL) and β-glucosidase (4.85 ± 0.42 U/mL) was used to ferment pigeon pea roots (PPR) for obtaining bioactive genistein . Semi-solid-state fermentation (SSSF) with water was found to be the appropriate strategy for increasing genistein level in PPR. The genistein yield (0.37 ± 0.02 mg/g) in PPR fermented by P. rubens under the optimal conditions was 3.08-fold higher than that in the control (0.12 ± 0.02 mg/g). Scanning electron microscope results indicated that P. rubens utilized the nutrients in PPR for growth and could significantly destroy cell walls, thus contributing to the release of more genistein. The bioactivities of extracts from PPR fermented by P. rubens were higher than control. The present study provided a cost-effective SSSF approach to achieve higher yield of genistein from agrifood by-products PPR using the novel P. rubens . Industrial relevance A novel endophytic fungus P. rubens , capable of cell wall hydrolysis and genistin deglycosylation , was used to ferment PPR using SSSF strategy to obtain higher yield of bioactive genistein. The present study developed a method associated with advantages of simple operation, low cost, low energy consumption and environmental friendliness for the effective utilization of agrifood by-products PPR in food , nutraceutical, and other industrial fields. Also, P. rubens exhibited promising potential in fermentation fields for improving yields of other bioactive aglycones from food and medicinal resources.