Determinação da concentração do ácido kójico a partir da fermentação do arroz e desafios na divulgação científica

Abstract

The production of kojic acid, a bioactive compound widely used in the cosmetic industry due to its skin-lightening and antioxidant properties, predominantly occurs through the fermentation of substrates such as rice by fungi of the genus Aspergillus or Penicillium. However, internet videos have popularized tutorials for the homemade production of this compound, often without considering the associated risks, such as microbiological contamination and the formation of toxic compounds. In this thesis, experiments were conducted following internet tutorials while adhering to methodological and scientific standards. The fungus Aspergillus niger and a wild strain isolated from cooked rice samples were used in different culture media, as follows: Solid cultivation medium composed of 20 g of cooked rice; Cultivation medium A, composed of 20 g of cooked rice per 1 L of distilled water; Cultivation medium B, composed of 100 g of glucose, 1g of KH¢PO¤, 0.5 g of MgSO¤, 0.1 g of ZnSO¤, and 2.5 g of yeast extract, formulated for 1 L of distilled water; Cultivation medium C, composed of 20 g of cooked rice, 100g of glucose, 1 g of KH¢PO¤, 0.5 g of MgSO¤, 0.1 g of ZnSO¤, and 2.5 g of yeast extract. Kojic acid concentrations were quantified using UV-VIS spectrophotometry. The results demonstrated that the solid medium was the most efficient, yielding 22.19 g/L for Aspergillus niger and 18.35 g/L for the wild strain. Conversely, medium B exhibited the lowest detectable kojic acid production. In the homemade methods, although microorganism growth was observed, no kojic acid formation was detected, highlighting the impracticality of the technique without strict control conditions, such as asepsis, temperature, and pH regulation. In addition to the experiments, a video was produced for social media to raise public awareness about the dangers and limitations of home fermentation practices involving fungi. The video highlighted the absence of positive results in domestic experiments, reported the high levels of microbiological contamination observed, and emphasized the need for adequate infrastructure for the safe production of kojic acid. The results of this study demonstrate that kojic acid production depends on specific conditions, including pH control, temperature regulation, asepsis, and the use of appropriate culture media. These fermentation conditions are difficult and unlikely to be safely replicated in homemade practices.