Carbon dioxide (CO₂) is a major component of the greenhouse gas; in the meantime it is also a valuable carbon resource. Creating novel biosynthetic pathways to produce petro-chemicals from CO₂ using solar energy as a sole energy source would be a promising approach to address the global issues on shortage of resources and energy. The success of such an approach is of great significanceto the sustainable development of industries.

As one of the representatives of cheap, bulk petrochemical products, acetone is widely used as an organic solvent and industrial raw material. In China, more than one million tons acetone is consumed annually, but half of which relies on imports. Natural cyanobacteria can rapidly grow on CO₂ by photosynthesis, but it cannot synthesize acetone due to lack of acetone synthetic pathway.

A research group led by Prof. LI Yin and Dr. ZHOU Jie at the Institute of Microbiology, Chinese Academy of Sciences (IMCAS), designed and created a modularized acetone synthetic pathway in cyanobacterium Synechocystis sp. PCC 6803. Biosynthesis of acetone from CO₂  was achieved by optimizing native photosynthetic carbon fixation module and introducing two optimized exogenous modules of acetyl transformation and decarboxylation. This work presented firm evidence showing that ketones can be biotechnologically produced from CO₂. Moreover, the novel strategy of designing and assembling a modularized pathway can be used as a reference for production of other bulkpetrochemical products from CO₂. 

The work has been available online in Metabolic Engineering since 28th March. It is part of the project “Synthetic Cell Factory” supported by the National Program on Key Basic Research Project of China.

Full article can be accessed at http://dx.doi.org/10.1016/j.ymben.2012.03.005.

Fig. Modularized biosynthetic pathway of acetone from carbon dioxide constructed in Synechocystis 6803 (Image by IMCAS)