In a groundbreaking development for sustainable agriculture and industrial biotechnology, researchers have engineered a salt-resistant bacterium to efficiently convert carbon dioxide (CO2) into valuable bioproducts. This innovation, published in *Advanced Science*, could significantly enhance carbon capture and utilization (CCU) technologies, offering new avenues for reducing greenhouse gas emissions and producing eco-friendly agricultural inputs.
The study, led by Chi Wang from the School of Biology and Biological Engineering at South China University of Technology, focuses on the bacterium *Halomonas TD*. Through adaptive laboratory evolution, the team created a strain called TD80, which exhibits enhanced acetate-utilizing capacity. This capability is driven by a mutation in the *aceE* gene, which encodes pyruvate dehydrogenase, a key enzyme in acetate metabolism.
“Our goal was to improve the bacterium’s ability to thrive in saline CO2-derived electrolytes (CDE) and boost its carbon conversion rate (CCR),” Wang explained. “By engineering TD80, we’ve demonstrated that it can efficiently produce a range of high-value bioproducts, including polyhydroxyalkanoates (PHAs), ectoine, and even enzymes like superoxide dismutase (SOD).”
The implications for the agriculture sector are substantial. PHAs, for instance, are biodegradable plastics that can be used for packaging and agricultural films, reducing reliance on petroleum-based products. Ectoine, a compatible solute, has applications as a biostimulant and crop protectant, enhancing plant resilience to environmental stresses. SOD, an antioxidant enzyme, can be used in food preservation and as a feed additive to improve animal health.
In fed-batch studies, the recombinant TD80 strains achieved impressive yields of 26.0 g/L ectoine and 29.6 g/L PHB. Furthermore, the researchers designed a non-canonical pathway to recycle excess malonyl-CoA into PHB, increasing its content from 60 wt% to 80 wt%. By co-producing ectoine and PHB, the team boosted the CCR of CDE-to-product up to 53.7 mol%, showcasing the platform’s potential for efficient CO2 upcycling.
The study also explored the bacterium’s ability to grow on formate alone, aiming for full utilization of CDE. The establishment of a technology and economic assessment (TEA) confirmed the platform’s efficiency and economic viability, paving the way for scalable carbon footprint reduction strategies.
“This research opens up new possibilities for sustainable agriculture and industrial biotechnology,” Wang noted. “By harnessing the power of engineered microbes, we can create a circular economy that not only reduces CO2 emissions but also produces valuable bioproducts that benefit various industries, including agriculture.”
The findings highlight the potential of biohybrid systems in addressing global CO2 emissions while simultaneously producing high-value bioproducts. As the world seeks innovative solutions to combat climate change, this research offers a promising pathway for integrating carbon capture and utilization into mainstream agricultural and industrial practices.