Ethylene production has been achieved in cyanobacteria by introducing an exogenous ethylene forming enzyme(EFE) that using the TCA intermediate 2-oxoglutarate(2-OG) as one of its substrates.NtcA is a global nitrogen regulator.2-OG provides the carbon skeleton for the assimilation of nitrogen and can affect C/N balance by regulating the activity of NtcA.