Overview
Light-controlled pigment synthesis in organisms is a promising field in synthetic biology. Due to time constraints during iGEM relatively short annual cycle, we were unable to fully realize the designed experiments in the laboratory by the final delivery. After the wiki freeze, we will continue to refine the experimental work. This page presents the proposed future experiments.
Expanding the Spectrum of Synthetic Pigments: Synthesis of Red Pigment
Deficiency: The red pigment 6-chloroindigo was not specially targeted in the project, making a color gap for broader applications.
Solutions: Replace the exogenous additive potassium bromide with sodium chloride to allow the existing halogenase fusion protein (SttH-L3-Fre) to catalyze the chlorination of tryptophan.
Future Goals: Synthesize the red pigment 6-chloroindigo and test its dyeing properties to expand the application scope of the engineered bacterial system.
Complete Validation of the Green Pigment Expression Pathway
Deficiency: Limited by the project timeline, the experimental validation of the entire 4,4'-dinitroindigo synthesis pathway was not completed; only preliminary analysis of protein expressions in E. coli was conducted.
Solutions: Further validate the pathway through wet-lab experiments combined with dry-lab modeling, optimizing promoter selection and enhancing enzyme activity.
Future Goals: Improve the nitration capability of tryptophan and increase the overall conversion efficiency for the synthesis of the green pigment.
Pigment Expression by Three E. coli Strains in Co-culture
Deficiency: The three strains producing blue, purple, and green pigments were constructed and their light-controlled dye production was only validated individually, not in a mixed culture.
Solutions: Evaluate the pigment production status of the different strains when they are mixed together.
Future Goals: Achieve the operation of the complete system that the mixed strains can work synergistically to express pigments on demand.
Safety: Integrating Modules into Amino Acid Auxotrophic E. coli
Deficiency: During the experimental stage, standard E. coli DH5α and BL21(DE3) strains were used for convenience, which lack further biocontainment features.
Solutions: Integrate genetic components into amino acid auxotrophic E. coli strains for expression.
Future Goals: Ensure the painting system cannot survive outside the specific medium, thereby further ensuring biocontainment.