The study on the microbe, K. rhaeticus, used two different culture media: HS-glucose media and coconut water media. The culture conditions included shaking and stationary cultures, with the addition of antibiotics, cellulase, and ethanol to promote pellicle formation. The microbe’s cells were inoculated into the culture media and grown at 30°C. The culture media was supplemented with l-tyrosine, copper salts, and other substances to promote melanin production.
For the purposes of this study, the microbe’s cells were used to produce melanated pellicles, which were then used to study the production of eumelanin. The pellicles were grown in a two-step process, first in a sterile culture container and then in a larger container with a larger volume of media. The pellicles were then washed and placed in a eumelanin development buffer to produce the melanin.
The study also used optogenetic constructs to express specific genes, such as the tyr1 gene, and to study the production of eumelanin in response to blue light. The results of the study demonstrated the use of K. rhaeticus as a model organism for the production of eumelanin and the development of optogenetic systems.