Synthetic biology toolkit for engineering Cupriviadus necator H16 as a platform for CO2 valorization

BackgroundCO2valorization is one of the effective methods to solve current environmental and energy problems, in which microbial electrosynthesis (MES) system has proved feasible and efficient.Cupriviadus necator(Ralstonia eutropha) H16, a model chemolithoautotroph, is a microbe of choice for CO2conversion, especially with the ability to be employed in MES due to the presence of genes encoding [NiFe]-hydrogenases and all the Calvin–Benson–Basham cycle enzymes. The CO2valorization strategy will make sense because the required hydrogen can be produced from renewable electricity independently of fossil fuels.Main bodyIn this review, synthetic biology toolkit forC. necatorH16, including genetic engineering vectors, heterologous gene expression elements, platform strain and genome engineering, and transformation strategies, is firstly summarized. Then, the review discusses how to apply these tools to makeC. necatorH16 an efficient cell factory for converting CO2to value-added products, with the examples of alcohols, fatty acids, and terpenoids. The review is concluded with the limitation of current genetic tools and perspectives on the development of more efficient and convenient methods as well as the extensive applications ofC. necatorH16.ConclusionsGreat progress has been made on genetic engineering toolkit and synthetic biology applications ofC. necatorH16. Nevertheless, more efforts are expected in the near future to engineerC. necatorH16 as efficient cell factories for the conversion of CO2to value-added products.