Aims
Zinc oxide nanoparticles (ZnONPs) were successfully synthesized using the culture filtrate of the endophytic fungus Alternaria tenuissima as a rapid, eco‐friendly and cost‐effective method.
Methods and Results
The rapid synthesis of ZnONPs was completed after 20 min as confirmed by UV–Vis spectroscopy. The synthesized ZnONPs showed a single‐phase crystalline structure. Dynamic light scattering analysis showed that the synthesized ZnONPs were monodispersed and the recorded polydispersity index value was 0·311. Zeta potential value of –23·92 mV indicated the high stability of ZnONPs. Transmission electron microscope revealed the spherical shape and the mean particle size was 15.45 nm. Functional groups present in the prepared samples of ZnONPs were confirmed by Fourier transform infrared spectroscopy. Additionally, the biological activities of in vitro antimicrobial, anticancer, antioxidant as well as the photocatalytic activities were evaluated. ZnONPs showed broad spectrum of antimicrobial potential against all the tested plant and human pathogens. Based on the MTT assay, ZnONPs inhibited the proliferation of normal human melanocytes, human breast and liver cancer cell lines with IC50 concentrations of 55·76, 18·02 and 16·87 µg ml−1. ZnONPs exhibited promising antioxidant potential with 50% inhibitory concentration of 102·13 µg ml−1. Moreover, ZnONPs showed efficient degradation of methylene blue dye.
Conclusions
The synthesized ZnONPs showed promising activities that can be better explored in the near future for many medical, agricultural and industrial applications.
Significance and Impact of the Study
This study suggests a new and alternate approach with the excellent biotechnological potentiality for the production of ZnONPs which could open up the way for the industrial manufacture of nanoparticles using microbial platforms.
Mycophenolic acid (MPA) is a promising drug owing to its immunosuppressive and biological activities. In this study, two strains of Penicillium roqueforti designated as AG101 and LG109 were selected among several strains isolated from Roquefort cheese samples on the basis of their activity for MPA-producing ability. The appropriate fermentation conditions necessary for MPA biosynthesis by the two respective fungal strains were investigated. These conditions included selection of the cultivation medium, agitation rate, incubation temperature, fermentation time, pH value, inoculum size, and fermentation medium volume. Maximum MPA productivities were maintained when the fermentation process was carried out using a medium composed of (g l(-1)): Sucrose, 30; peptone, 5.0; KH2PO4, 1.0; MgSO4·7H2O, 0.5 and KCl, 0.5; pH 6.0, inoculated with an inoculum size of 6.0 % (v/v), and incubated at 25 °C for 10 days at 120 rpm. The potentiality of both P. roqueforti strains for further improvement of MPA production was applied by mutagenesis through exposure to irradiation by ultraviolet rays (UV, 254 nm) for different periods of time and gamma rays at various doses (KGy). The dry cell weight of both irradiated fungal strains showed a greater reduction when irradiated either with UV or gamma rays. However, the MPA yield of both strains was increased by 1.27-1.39 fold when irradiated with UV rays and by 2.11-2.33 fold when irradiated with gamma rays, as compared with the respective controls (non-irradiated cultures). These findings indicate the future possibility to reduce the cost of producing fermentation-based drugs.
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