Detection of kojic acid producing ability in Aspergillus sp.

Abstract

Kojic acid is widely and highly applicable in food industry, pharmaceutical science and cosmetic production due to its biological activities. Importantly, it is a fundamental component for whitening cream production in cosmetics. Aspergillus sp. is one of the very important filamentous fungi due to its high application in human activities. They have ability to produce kojic acid due to the presence of genes related to the kojic acid synthetic pathway. In this study, PCR was performed in order to amplify the target DNA sequences related to kojic acid synthesis in Aspergillus sp. A range of pH values (4.6, 5.0, 6.0, 7.0) and different durations of fermentation (8, 10, 12 and 14 days) were applied to optimize kojic acid production. Thin-layer chromatography and highperformance liquid chromatography were used to detect the quantitative of kojic acid in the sample. Using colorimetric method, the yield of kojic acid was determined. The result showed that two strains of Aspergillus VTCC-F-1132 and VTCC-F-910 contained the genes kojA, kojT, kojR related to kojic acid biosynthesis pathway. However, VTCC-F-1132 strain had ability to produce kojic acid higher than VTCC-F-910. At pH 5.0 in 14 days, VTCC-F-1132 strain was produced highest yield 237.33±15.77 μg/mL. This was the first study of kojic acid producing from VTCC-F-1132 and VTCC-F-910 strains. Key words: kojic acid, Aspergillus sp., PCR, thin-layer chromatography, high-performance liquid chromatography, colorimetric method