Biological and Therapeutic Applications of Gallic Acid Produced by <i>Aspergillus terreus</i> PQ344456 Using Submerged Fermentation

In this research, <i>Aspergillus terreus</i> PQ344456 fungi was utilized to produce gallic acid through techniques, such as submerged fermentation, that showed a maximum production rate of 188.58 ± 0.27 mg/mL at 96 h. <i>Aspergillus terreus</i> PQ344456 isolates were identified through visualization of phenotypic and genotypic characteristics through procedures that involved the implementation of 18S rRNA sequencing and investigation of the most optimal fermentation conditions through testing the impact of tannic acid levels, pH, and temperature on production rate, in which their values tended to be found optimal at 1.5%, 5, and 30 °C, respectively. Moreover, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was employed to assess gallic acid's antioxidant activity, displaying a half-maximal inhibitory concentration (IC₅₀) value of 54.96 μg/mL. In addition, antibacterial effectiveness was evaluated against various pathogenic strains. The minimum inhibitory concentration (MIC) value appeared to range from 0.0625 to 8 mg/mL and inhibition zone diameters from 29 ± 3.71 mm to 41 ± 1.00 mm. Antifungal activity was also assessed, with inhibition zones ranging from 12 ± 3.21 mm and MIC values from 0.125 to 8 mg/mL. Summarizing the research findings, <i>Aspergillus terreus</i> PQ344456 showed efficacy when used to produce gallic acid that was found to offer considerable potential to be used as an antioxidant, antibacterial, and antifungal agent concurrently with providing features like safety, accompanied by the fact that gallic acid is of natural origin.