Isoprene hydrocarbon production using genetically engineered cyanobacteria

A method of producing isoprene hydrocarbons in a cyanobacteria sp., the method comprising:

• introducing an expression cassette that comprises a nucleic acid encoding an isoprene synthase (IspS) into the cyanobacteria sp., to obtain cyanobacteria comprising the nucleic acid, wherein the nucleic acid encoding isoprene synthase is codon optimized and is operably linked to a psbA2 promoter, and further wherein the nucleic acid has at least 90% identity to the region of SEQ ID NO:3 that encodes the IspS;
• culturing the cyanobacteria under conditions to achieve DNA homoplasmy;
• and
• culturing the cyanobacteria under conditions in which the nucleic acid encoding isoprene synthase is expressed.