Evaluation of the photolysis of staphyloxanthin from Staphyloccus aureus using 460 nm wavelength of LED light

Abstract

Staphyloxanthin is a bright yellow carotenoid pigment synthesized by Staphylococcus aureus bacteria on cell membranes. Staphyloxanthin has anti-oxidant properties, protecting Staphylococcus aureus bacteria against oxidizing agents capable of destroying and causing bacterial cell death. The light at 460 nm light has been shown to cause photolysis of staphyloxanthin, which directly affects the oxidation resistance of S. aureus bacteria. Test results showed that 460 nm wavelength light at 200 mW/cm² energy level caused optical density at 470 nm of staphyloxanthin crude extract reduced up to 41.1 % after 5 minutes of illumination. The photolysis of staphyloxanthin crude extract continued after 5 minutes of irradiation, causing the reduction of the absorbance of the extract up to 74.8 %. However in the experiment applying 460 nm light directly on bacterial biomass, the staphyloxanthin photolysis effect of the light was reduced partially, and the efficiency of photolysis process over time was slower than the effect of direct light onto the crude extract. The results of the study confirm the potential of the 460 nm light to induce photolysis of the S. aureus staphyloxanthin pigment, which is a necessary first step to further study the treatment of this bacterium with 460 nm light in the future.