Improving the medium composition for the production of the natural blue-violet pigment violacein by a new Janthinobacterium sp. isolate

The interest in natural compounds has increased primarily due to their beneficial health and environmental aspects. However, natural sources of some compounds, such as bluish pigments, are limited, requiring the development of efficient processes to meet commercial demands. This study isolated a blue-violet bacterium from spoiled cooked rice and identified it as a potential new species of Janthinobacterium through 16S rDNA analysis. Ultra-high performance liquid chromatography-tandem mass spectrometry analyses confirmed that the blue-violet pigment violacein was responsible for the bluish color. In laboratory conditions, different carbon and nitrogen sources were evaluated in submerged culture media to enhance pigment production. Glycerol did not result in significant pigment production by this strain, as expected from previous reports. Instead, a culture medium composed of yeast extract and fructose yielded higher pigment production, reaching about 113.68 +/- 16.68 mg l-1 after 120 h. This result provides crucial insights for future studies aiming for sustainable and commercially viable violacein production. Based on a bioeconomy concept, this approach has the potential to supply natural and economic bluish pigments for various industrial sectors, including pharmaceutical, cosmetic, and food.