Archaea and Bacteria are the two primary domains of life on earth. They encode vast but often non-overlapping biosynthetic potential with applications in making biochemicals such as materials, medicines and biofuels. The current bacterial chassis often use expensive sugars as feedstocks, which limits profitability. Using the archaeal model, Methanococcus, we are developing an archaeal chassis that feeds on inexpensive CO2 and H2 instead of sugars for next-generation biochemical productions.

The current microbial chassis, E. coli, cyanobacteria and yeast, utilize sugars or photosynthesis to initiate metabolic pathways. M. maripaludis' chassis would have a broad impact on the bioeconomy because it only requires H2 and CO2, which are abundant in quantity. This makes it economically attractive. For M. maripaludis, autotrophic growth is rapid, anaerobic product formation offers higher yields, and it costs less compared to aerobic systems. The substrates H2 and CO2 can be generated easily, and the major metabolic waste, CH4, is already a biofuel contributing to an efficient energy cycle (Lyu et al, 2016, ACS Syn Biol). Methanogens are important microorganisms that are responsible for producing the majority of the atmospheric methane in environment. With new genetic tools for M. maripaludis, archaea can be promoted as the next generation chassis for synthetic biology.

Last year we showed that M. maripaludis is a genetically tractable model organism for archaea and an excellent chassis for exploring the potential for biochemical synthesis. As a proof-of-concept we've shown that we can engineer M. maripaludis to take in H2 and CO2 and produce small amounts of geraniol, a high-value chemical used in perfumes, fruit flavors, and mosquito repellent.

This summer we developed a set of genetic tools and techniques to make engineering M. maripaludis more convenient. We planned to increase the metabolic efficiency for producing biochemicals. With these tools we would be able to engineer complex metabolic pathways and create synthetic operons for biosynthesis of more valuable compounds.