Recovery of a marine cyanobacterial recombinant product using fish-feed organisms

A novel approach for the recovery of recombinant products expressed in marine cyanobacteria, utilizing the fish-feed organism, brine shrimp (Artemia salina), is presented. Chloramphenicol acetyltransferase (CAT) was highly expressed in the marine unicellular cyanobacterium, Synechococcus sp. NKBG15041c, under a c-phycocyanin promoter derived from Synechococcus sp. PCC7942. These recombinant marine cyanobacteria were recovered using brine shrimp. CAT activity was retained in brine shrimp and increased with the time they were fed with recombinant cyanobacteria expressing CAT. Subsequently, the brine shrimp were fed to medaka fish. About 80% of added CAT was observed in the digestive organs of medaka for more than 9 h after feeding. These results demonstrate a novel process that can deliver a recombinant product to fish via fish-feed organisms without any purification steps.