Detoxifying Mars with Synthetic Biology

Perchlorate is a widespread environmental contaminant resulting from anthropogenic sources such as rocket fuel combustion and pyrotechnics. On Mars, perchlorate concentrations can be found up to 1% where they pose a dual challenge: endangering astronauts by disrupting thyroid function and contaminating water supplies. Despite the hazardous effects of perchlorate, it also offers a potential source of oxygen for extraterrestrial missions. These characteristics have led to synthetic biology efforts aimed at leveraging perchlorate metabolism for Mars detoxification and oxygen production. The enzymatic breakdown of perchlorate relies on chlorite dismutase (Cld), a key enzyme that catalyzes the conversion of chlorite into oxygen and innocuous chloride. Previous work has demonstrated that Cld acts as the rate-limiting step in perchlorate reduction, leading to the accumulation of toxic chlorite and limiting its efficiency in both bioremediation and space exploration applications. To enhance Cld activity, this study employed a protein engineering approach combined with analytical genomics to identify and optimize key amino acid residues influencing enzymatic performance. By analyzing the nucleotide and amino acid sequences of Cld variants with differing reaction rates, we identified candidate residues for modification. Structural modelling using AlphaFold and molecular visualization with PyMol enabled us to predict the effects of specific amino acid substitutions on enzyme stability and catalytic efficiency. Optimizing Cld for increased efficiency has significant implications for both Mars missions and terrestrial water decontamination efforts. By accelerating perchlorate reduction and oxygen production, this research supports the development of sustainable life-support systems for space exploration while also improving bioremediation strategies on Earth. Future work will focus on validating engineered Cld variants in experimental settings to further refine their application in diverse environmental and extraterrestrial contexts.