Moreover, a novel poly(3-hydroxybutyrate) (PHB) depolymerase
from a thermophilic Streptomyces sp.
Activities of the Purified PLA Depolymerase
for Various Substrates
Degradation rate of HA/PHBV nanofibrous films was investigated, it was found that in the presence of polyhydroxybutyrate depolymerase
, the degradation rate was very fast.
A key bacterial enzyme called capsule depolymerase
(CapD) anchors the capsule to the cell surface.
A breakthrough in PHB molecular biology was the presentation of the first three-dimensional X-ray structure of a type II extracellular single-domain depolymerase
Phenol, Polyhydroxyalkanoate, depolymerase
, electron microscope.
and glycoside hydrolases of Bacillus spp.
In this process, the PHB-degrading bacteria and fungi excrete extracellular depolymerases
that hydrolyze the solid polymer into water-soluble monomers and oligomers that are consumed as nutrients by the microorganisms .
Selection of the microbial source for pectinase production depends on several features, such as the type of culture (solid-state or submerged fermentation), number and type of the produced pectinases (esterases, hydrolytic depolymerases
and eliminative depolymerases
), pH and thermal stability of the enzymes [1,10-13].
2 Intracellular P(3HB) Depolymerases
and Degradation Systems
Among the depolymerases
, polygalacturonase is the major enzyme with a hydrolytic function and lyases (or transeleminases) which cleaves glycosidic bonds forming unsaturated product[DELTA](4,5-D-galacturonate) through transelimination reaction .
Increasing amounts of the 4-hydroxy- repeating unit decreases the well known brittleness of P(3HB) and leads to clear, tough films with good susceptibility to both PHA depolymerases
and lipases for biodegradation.