A. fertilissima is the first cyanobacterium where PHB accumulation reached up to 85% (dcw) by manipulating the nutrient status of the culture medium. The polymer extracted from A. fertilissima exhibited comparable material properties with the commercial polymer. As compared with heterotrophic bacteria, carbon requirement in A. fertilissima for PHB production is lower by one order magnitude; thus, low-cost PHB production can be envisaged