Production of poly(hydroxyalkanoic acid).

Poly(hydroxyalkanoic acid) [PHA] is accumulated by numerous microorganisms as an energy reserve material under unbalanced growth conditions in the presence of excess carbon source. In spite of being a good candidate for biodegradable thermoplastics, their high price compared with conventional plastics currently in use has limited their availability in a wide range of applications. With the aim of reducing the high production cost of PHA, much effort is currently being devoted to improve productivity by employing various microorganisms and by developing efficient culture techniques. Several processes recently developed and employed for the production of PHA by various bacteria are described.