Production of Pha by Recombinant Organisms

Polyhydroxyalkanoates (PHA) are biodegradable, thermoplastic polyesters produced from renewable carbon sources by a number of bacteria. However, their application is limited by high production costs. One of the strategies aimed to reduce their costs is the development of recombinant strains able to utilize different carbon sources. Many bacteria are naturally capable of accumulating biopolyesters composed of 3-hydroxy fatty acids as intracellular inclusions, which serve as storage granules. Recently, these inclusions have been considered as nano/ microbeads with surface-attached proteins, which can be engineered to display various proteinbased functions that are suitable for biotechnological and biomedical applications. Natural PHA producers have become accustomed to accumulating PHA during evolution; they often have a long generation time, relatively low optimal growth temperature, are often hard to lysis and contain pathways for PHA degradation. This led to the development of recombinant PHA producers, capable of high PHA accumulation and/or free of PHA degradative pathways. This review summarizes the production of PHA by recombinant bacteria as well as some higher organisms in brief.