Fixing Carbon Dioxide With Cyanobacteria

Japanese researchers have used genetic engineering to improve the conversion rate of carbon dioxide to succinate by cyanobacteria.

AsianScientist (Jun. 20, 2018) – A research group in Japan has genetically engineered cyanobacteria that are better at converting carbon dioxide into succinate, which is widely used as a raw ingredient for petrochemicals. They reported their findings in Metabolic Engineering.

Carbon dioxide is abundant in the atmosphere, and scientists have long sought a means to convert it efficiently into materials or energy sources. Cyanobacteria are known to take up atmospheric carbon dioxide and generate succinate, a useful chemical product.

In the present study, researchers led by Professor Tomohisa Hasunuma at Kobe University, Japan, have found that succinate production levels increase when cyanobacteria are grown above the ideal temperature for cell growth. The cyanobacterium used in this study (Synechocystis sp. PCC 6803) is one of the most popular strains of cyanobacteria used in research labs worldwide.

The team discovered that this strain of cyanobacterium produces succinate at 37 degrees Celsius, which is seven degrees Celsius higher than the optimal temperature for cell growth. Using dynamic metabolome analysis, they clarified the mechanism for producing succinate at high temperatures and showed that the enzyme phosphoenolpyruvate carboxylase (PEPC) is involved in the bottleneck reaction.

The group then genetically engineered a recombinant strain of cyanobacteria which has higher PEPC activity than the wild type strain. By improving the PEPC reaction and growing cyanobacteria at 37 degrees Celsius, they managed to raise the production rate of succinate to 7.5 times higher than that reported in previous studies.

“This study is an important step towards producing bio-succinate from carbon dioxide. We now aim to increase the production of succinate by refining the metabolic pathway,” said Hasunuma.

“By targeting various metabolic systems, this line of research could make large contributions in basic research into metabolic pathway control structures. Our findings may also be useful in applied research on substance production,” he added.



The article can be found at: Hanusuma et al. (2018) Temperature Enhanced Succinate Production Concurrent with Increased Central Metabolism Turnover in the Cyanobacterium Synechocystis sp. PCC 6803.

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Source: Kobe University; Photo: Pixabay.
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