Cyanobacteria produce plastic naturally as a by-product of photosynthesis—and they do it in a sustainable and environmentally friendly way. Researchers at the University of Tübingen have succeeded for the first time in modifying the bacteria’s metabolism to produce this plastic in quantities to be used industrially.
Around 370 million tons of plastics are currently produced each year. Plastic can be used in a variety of ways and is inexpensive but it is the cause of increasing environmental problems.
A solution to these problems may lie in a strain of cyanobacteria with surprising properties. Cyanobacteria of the genus Synechocystis produce polyhydroxybutyrate (PHB), a natural form of plastic. PHB can be used in a similar way to the plastic polypropylene but is rapidly degradable in the environment. However, the amount produced by these bacteria is usually very small. The researcher succeeded in identifying a control system in the bacteria. After removing the corresponding regulator and implementing several further genetic changes, the amount of PHB produced by the bacteria increased for more than 80% of the cell’s total mass.
Since cyanobacteria only need water, CO2 and sunlight, the researchers believe they are ideal candidates for climate-friendly and sustainable production.
Tim Orthwein et al. The novel PII-interactor PirC identifies phosphoglycerate mutase as key control point of carbon storage metabolism in cyanobacteria, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2019988118
Moritz Koch et al. Maximizing PHB content in Synechocystis sp. PCC 6803: a new metabolic engineering strategy based on the regulator PirC, Microbial Cell Factories (2020). DOI: 10.1186/s12934-020-01491-1