Bacteria and archaea could be used to monitor stored carbon dioxide (CO2) and convert it into useful products, such as ethanol and acetate, say researchers at the Oban-based Scottish Association for Marine Science (SAMS) and the University of Oslo.
In an Opinion published in Trends in Biotechnology, they discuss how new bioinformatics tools would enable researchers to read shifts in microbial community genetics - making it possible to detect potential CO2 leaks - and how such analyses could contribute to making large-scale capture and storage of CO2 feasible.
Rising CO2 levels contribute to both global warming and ocean acidification. Capturing this CO2 from large point sources and storing it in underground geological formations, a process called carbon capture and storage (CCS), is considered one promising way to keep it out of the atmosphere and reduce its effects. The CO2 is buried in porous and permeable rock that is blanketed with at least one layer of impermeable rock.
But this potential solution comes with risks, says Dr Natalie Hicks (@DrNatalieHicks), a biogeochemist at SAMS. "One of the biggest concerns with carbon capture storage is the environmental impacts if there is a leak," she said. "How would we know about it, how would we detect it, and what would the environmental implications be."
Dr Hicks and her co-authors, who include a multidisciplinary team of geneticists and engineers, say that in addition to physical methods of monitoring CCS sites, such as measuring CO2 levels, it should be possible to monitor the bacteria and archaea living in sediment overlying these sites to detect potential leaks. They point to a simulated CO2 leak experiment previously conducted in a sub-seabed reservoir near to SAMS that detected changes in the microbial communities around the reservoir, before other organisms were visibly affected.
Dr Hicks and her colleagues further argue that in addition to monitoring for leaks, bacteria and archaea could help convert stored CO2 into useful products, including ethanol, acetate, acetone, lactate, and methane. Metabolic pathways in bacteria that assimilate CO2 are well known, but others have been discovered in recent years that convert CO2 into these chemicals.