Home
Resources
Publications
Enzymatic Degradation Processes of poly[(R)-3-hydroxybutyric Acid] and poly[(R)-3-hydroxybutyric acid-co-(R)-3-hydroxyvaleric Acid] Single Crystals Revealed by Atomic Force Microscopy: Effects of Molecular Weight and Second-Monomer Composition on Erosion Rates

Enzymatic Degradation Processes of poly[(R)-3-hydroxybutyric Acid] and poly[(R)-3-hydroxybutyric acid-co-(R)-3-hydroxyvaleric Acid] Single Crystals Revealed by Atomic Force Microscopy: Effects of Molecular Weight and Second-Monomer Composition on Erosion Rates

Keiji Numata, Yoshihiro Kikkawa, Takeharu Tsuge, Tadahisa Iwata, Yoshiharu Doi, Hideki Abe

Biomacromolecules. Jul-Aug 2005;6(4):2008-16.

PMID: 16004439

Abstract:

Enzymatic degradation processes of poly[(R)-3-hydroxybutyric acid] (P(3HB)) and poly[(R)-3-hydroxybutyric acid-co-(R)-3-hydroxyvaleric acid] (P(3HB-co-3HV)) single crystals in the presence of PHB depolymerase from Ralstonia pickettii T1 were studied by real-time and static atomic force microscopy (AFM) observations. Fibril-like crystals were generated along the long axis of single crystals during the enzymatic degradation, and then the dimensions of fibril-like crystals were analyzed quantitatively. The morphologies and sizes of fibril-like crystals were dependent on the molecular weight and copolymer composition of polymers. For all samples, the crystalline thickness gradually decreased toward a tip from the root of a fibril-like crystal after enzymatic degradation for 1 h. The thinning of fibril-like crystals may be attributed to the destruction of chain-packing structure toward crystallographic c axis by the adsorption of enzyme. From the real-time AFM images, it was found that at the initial stage of degradation the enzymatic erosion started from the disordered chain-packing region in single crystals to form the grooves along the a axis. The generated fibril-like crystals deformed at a constant rate along the a axis with a constant rate after the induction time. The erosion rate at the grooves along the a axis increased with a decrease of molecular weight and with an increase of copolymer composition. On the other hand, the erosion rate along the a axis, at the tip of the fibril-like crystal, was dependent on only the copolymer composition, and the value increased with an increase in the copolymer composition. The morphologies and sizes of fibril-like crystals were governed by both the erosion rates along the a axis at the grooves and tip of fibril-like crystals. In addition, we were able to estimated the overall enzymatic erosion rate of single crystals by PHB depolymerase from the volumetric analysis.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP29435481	Poly[(R)-3-hydroxybutyric acid]		29435-48-1	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: