Guanidine Degradation Enzyme and Methods of Use

Presented herein are Synechococcus strains engineered to express the bacterial ethylene-forming enzyme (EFE) that exhibit unstable ethylene production due to toxicity and genomic instability induced by accumulation of the EFE-byproduct guanidine. Co-expression of EFE and Sll1077 significantly enhanced genomic stability and enabled the resulting Synechococcus strain GD-EFE7942 to achieve sustained high-level ethylene production. The engineered strains and methods disclosed herein are useful for guanidine degradation pathways and for ethylene bioproduction in cyanobacteria.