Construct heterologous omega-3 fatty acid production Arthrospira strain

The utilization of Arthrospira as a host cell in the production of high-value substances has long been a goal. However, the success methods for DNA transfer systems in this organism have just recently been reported. One of them is our success in transferring DNA into Arthrospira platensis strain C1 using electroporation and transposon techniques as well as protecting DNA against host endonuclease. As a result, we used these strategies to create a heterologous omega-3 fatty acid producing Arthrospira strain. The omega-3 desaturase (desB) gene and its promoter from cyanobacterium Synechocystis PCC6803 were fused as an operon with the bacterial spectinomycin-streptomycin resistance (SmR) gene. This operon was inserted between the EZ-Tn5^TM transposase recognition sequences to construct a transposon cassette. The transposon cassette was transferred into Arthrospira C1 by electroporation and the transformed cell was screened on spectinomycin and streptomycin selective medium. Some transformants were able to survive and grow several rounds after being transferred under antibiotic selective pressure. The transformed desB and SmR genes in the genome of the transformant were detected by PCR. The results indicated that the heterologous desB-SmR operon could be transformed into Arthrospira C1 and its expression was driven by the heterologous cyanobacterial desB promoter. The ability of this promoter to stimulate the omega-3 fatty acids synthesis has been evaluated to identify the heterologous Arthrospira stain that produces omega-3 fatty acids.