A cell-free self-replenishing CO2-fixing system
Shanshan Luo, Paul P. Lin, Liang-Yu Nieh, Guan‐Bo Liao, Po‐Wen Tang, Chi Chen, James C. Liao
Abstract
Abstract Biological CO 2 fixation is so far the most effective means for CO 2 reduction at scale and accounts for most of the CO 2 fixed on Earth. Through this process, carbon is fixed in cellular components and biomass during organismal growth. To uncouple CO 2 fixation from growth and cellular regulation, cell-free CO 2 fixation systems represent an alternative approach since the rate can be independently manipulated. Here we designed an oxygen-insensitive, self-replenishing CO 2 fixation system with opto-sensing. The system comprises a synthetic reductive glyoxylate and pyruvate synthesis (rGPS) cycle and the malyl-CoA-glycerate (MCG) pathway to produce acetyl-coenzyme A (CoA), pyruvate and malate from CO 2 , which are also intermediates in the cycle. We solved various problems associated with the in vitro system, and implemented opto-sensing modules to control the regeneration of cofactors. We accomplished sustained operation for 6 hours with a CO 2 -fixing rate comparable to or greater than typical CO 2 fixation rates of photosynthetic or lithoautotrophic organisms.