Microbial Degradation of Polyhydroxyalkanoates

Annu Rev Microbiol. 2002;56:403-32. doi: 10.1146/annurev.micro.56.012302.160838. Epub 2002 Jan 30.


Polyesters such as poly(3-hydroxybutyrate) (PHB) or other polyhydroxyalkanoates (PHA) have attracted commercial and academic interest as new biodegradable materials. The ability to degrade PHA is widely distributed among bacteria and fungi and depends on the secretion of specific extracellular PHA depolymerases (e-PHA depolymerases), which are carboxyesterases (EC and EC, and on the physical state of the polymer (amorphous or crystalline). This contribution provides a summary of the biochemical and molecular biological characteristics of e-PHA depolymerases and focuses on the intracellular mobilization of storage PHA by intracellular PHA depolymerases (i-PHA depolymerases) of PHA-accumulating bacteria. The importance of different assay systems for PHA depolymerase activity is also discussed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Bacteria / genetics
  • Bacteria / isolation & purification
  • Bacteria / metabolism*
  • Biodegradation, Environmental
  • Carboxylic Ester Hydrolases / metabolism*
  • Intracellular Fluid / metabolism
  • Intracellular Fluid / microbiology
  • Molecular Sequence Data
  • Polyesters / chemistry
  • Polyesters / metabolism*
  • Sequence Homology, Amino Acid


  • Polyesters
  • Carboxylic Ester Hydrolases
  • poly(3-hydroxyalkanoic acid) depolymerase