BIODEGRADATION POLYHYDROXYALKANOIC ACIDS

Stimulated by the commercial availability of bacteriologically produce d polyesters such as poly[(R)-3-hydroxybutyric acid], and encouraged b y the discovery of new constituents of polyhydroxyalkanoic acids (PHA) , a considerable body of knowledge on the metabolism of PHA in microor ganisms has accumulated. The objective of this essay is to give an ove rview on the biodegradation of PHA. The following topics are discussed : (i) general considerations of PHA degradation, (ii) methods for iden tification and isolation of PHA-degrading microorganisms, (iii) charac terization of PHA-degrading microorganisms, (iv) biochemical propertie s of PHA depolymerases, (v) mechanisms of PHA hydrolysis, (vi) regulat ion of PHA depolymerase synthesis, (vii) molecular biology of PHA depo lymerases, (viii) influence of the physicochemical properties of PHA o n its biodegradability, (ix) degradation of polyesters related to PHA, (x) biotechnological aspects of PHA and PHA depolymerases.