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Aims:This study aims at immobilization of fungal mutants on nanosilica (NSi)carriers for designing efficient biosorbents as a significant new technology for decontamination practices and maximizing their heavy metal (HM) sorption proficiency through the experimental design methodology. Materials and Results: Endophytic fungal mutant strains, Chaetomium globosumEl26 mutant and Alternaria alternata S5 mutant were heat inactivated and then immobilized, each separately, on NSi carriers to formulate two separated nanobiosorbents. The formulated NSi-Chaetomium globosum El26 mutant (NSi-Chae El26 m) was investigated for Pb +2 uptake while, the formulated NSi-Alternaria alternata S5 mutant (NSi-Alt S5 m) was investigated for Cd +2 uptake, each through a batch equilibrium protocol. Before and after the metal sorption process, the designed nano-biosorbents were characterized via scanning electron microscopy, energydispersive X-ray spectroscopy, and Fourier transform infrared analysis. Sorption pH, contact time, sorbent concentration, and initial HM concentration were statistically optimized using a Box-Behnken design. Results showed that NSi-Chae El26 m was efficient in Pb +2 uptake with maximum biosorption capacities of 199.0, while NSi-Alt S5 m was efficient in Cd +2 uptake with maximum biosorption capacities of 162.0 mg g −1 . Moreover, the equilibrium data indicated that the adsorption of Pb +2 and Cd +2 by the tested nano-biosorbents fitted to the Freundlich isotherm. Conclusions: The formulated nano-biosorbents resulted in higher HM biosorption of metal ions from aqueous solution than that obtained by the free fungal biomass.The biosorption statistical modelling described the interactions between the tested sorption parameters and predicted the optimum values for maximum HM biosorption capacity by the two designed nano-biosorbents.Significance and Impact of The Study: These findings verify that members of the endophytic fungal genera Alternaria and Chaetomium are suitable to produce nanobiosorbents for decontamination practices after treatment by gamma mutagenesis, heat inactivation, and NSi immobilization. Moreover, statistical optimization can assist to evaluate the optimal conditions to produce such bioremediation material.

The bacterial wilt is a global destructive plant disease that initiated by the phytopathogenic Ralstonia solanacearum. This study display a novel biofabrication of silica/silver nanocomposite using Fusarium oxysporum-fermented rice husk (RH) under solid state fermentation (SSF). The biofabricated nanocomposite was characterized by XRD, UV–Vis. spectroscopy, DLS, SEM, EDX elemental mapping, and TEM analyses as well as investigated for anti-R. solanacearum activity. Response surface methodology was also processed for optimizing the biofabrication process and improving the anti-bacterial activity of the fabricated nanocomposite. Maximum suppression zone of 29.5 mm against R. solanacearum was reached at optimum RH content of 6.0 g, AgNO3 concentration of 2.50 mM, reaction pH of 6.3, and reaction time of 2 days. The anti-R. solanacearum activity of the fabricated nanocomposite was further improved by exposing the F. oxysporum strain to a gamma irradiation dose of 200 Gy. In conclusion, RH recycling under SSF by F. oxysporum could provide an innovative, facile, non-expensive, and green approach for fabricating SiO2/Ag nanocomposite that could be applied efficiently as an eco-friendly antibacterial agent to combat R. solanacearum in agricultural applications. Moreover, the developed method could serve as a significant platform for the designing of new nanostructures for broad applications.

Background The demand for natural coloring and preservative agents in food industry is increasing day by day as a result of awareness of the negative health effects of synthetic color preservatives. Consumers want foods with less processing, a longer shelf life, and clear labels that list only natural ingredients and food additives with familiar names that promote good health. In order to meet consumer demands and regain consumers' confidence in the safety of food products, the food industry was compelled to search for natural alternatives with strong antibacterial and antioxidant properties. Therefore, the objective of this study was to produce a microbial pigment that not only serve as food coloring agents but also provide health advantages owing to their bioactivities. Additionally, the potential use of anthraquinone pigment (AQP) as a natural food preservative compared to gamma irradiation was also examined to extend the shelf life of the beef burger and improve its hygienic quality. Results This study used Talaromyces purpureogenus AUMC2603 to produce the red natural pigment, which was identified as an anthraquinone pigment (AQP). According to the results, gamma (γ) radiation had no significant effect on AQP's antibacterial properties. However, it has a negative, considerable effect on antioxidant activity, where a large dose of γ-ray may change the antioxidant components and lessen the AQP's capacity to scavenge free radicals. Additionally, the γ ray-treated AQP had a strong cytotoxic activity in relation to a high γ-ray dose. As a result, it is suggested that AQP-containing foods should not be irradiated. The extracted AQP was applied as a food additive to improve the quality and increase the shelf life of beef burgers. Significant antibacterial and antioxidant action has been shown at 2% (w/v) AQP. The findings demonstrated that the treatment of beef burger with AQP decreased the initial total bacterial count and psychrophilic bacteria and extended the shelf-life of beef burger in comparison to the control (beef burger with no addition of AQP, butylated hydroxytoluene (BHT) or gamma radiation treatment). On the other hand, there was no substantial difference in the overall amount of mold and yeast or coliform at zero time. According to sensory characteristics, beef burgers had a shelf life of 6 days for controls and 9, 12, and 15 days for AQP-treated samples at 0.5, 1 and 2%, respectively, compared to γ- irradiated samples, 9 and 21 days, at 3 and 5 Kilo Gray (KGy), respectively. Conclusions This research provides a natural red pigment from Talaromyces purpureogenus with potent biological activities as antimicrobials and antioxidants to be applied as coloring, additive, and preservative agent in the food industry. Also, the tested pigment offers a powerful alternative to gamma irradiation for extending the shelf life of food products.