The world’s energy and global warming crises call for sustainable,renewable,carbon-neutral alternatives to replace fossil fuel resources.Currently,most biofuels are produced from agricultural crops and residues,which lead to concerns about food security and land shortage.Compared to the current biofuel production system,cyanobacteria,as autotrophic prokaryotes,do not require arable land and can grow to high densities by efficiently using solar energy,CO2,water,and inorganic nutrients.Moreover,powerful genetic techniques of cyanobacteria have been developed.For these reasons,cyanobacteria,which carry out oxygenic photosynthesis,are attractive hosts for production of fuels and chemicals.Recently,several chemicals including ethanol,isobutanol and isoprene have been produced by engineered cyanobacteria directly using solar energy,CO2,and water.Cyanobacterium is therefore a potential novel cell factory for fuels and chemicals production to address global energy security and climate change issues.
