Study and Effect of Agitation on Kojic Acid Production by Aspergillus oryzae in Liquid Fermentation

Kojic acid (KA) is an economically important molecule, due to its functions as an anti-inflammatory, antifungal, and facial skin-lightening agent. Considering the wide application of this metabolite, it is essential to study processes that increase or improve its production. The objective of this study was to evaluate the effect of agitation on fungal KA production. To evaluate the effect of agitation on fungal KA production, liquid medium fermentation was carried out using batch bioreactors with a capacity of one liter. The Aspergillus oryzae strain was used, with glucose as the sole carbon source. Three experimental factors were evaluated: illumination (light or darkness), agitation type (no agitation, bubbling, and tangential), and time (0, 24, 48, 72, 96, 120, 144, 168 h). The evaluated variables included pH, product-to-biomass yield, protein content, reducing sugar consumption, and KA concentration. The bubbling level with light for 144 h showed the highest efficiency by producing 7.86 ± 2.21 g KA/L. The production of KA in liquid medium with the fungus A. oryzae requires bubbling conditions with light to achieve the best yields and production. The findings in this study provide insights into the influence of agitation conditions on KA biosynthesis and its potential for scaling up industrial fermentation. However, future work could investigate the metabolic and genetic mechanisms of this enhanced production to generate more efficient biotechnological applications for KA production.