Structure and enzymatic degradation of poly(3-hydroxybutyrate) copolymer single crystals with an extracellular PHB depolymerase from Alcaligenes faecalis T1

Iwata, Tadahisa; Doi, Yoshiharu; Nakayama, Shinichi; Sasatsuki, Hironori; Teramachi, Shinya

doi:10.1016/s0141-8130(99)00031-8

Cited by 75 publications

(66 citation statements)

References 42 publications

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“…Both single crystals resemble closely those of P(3HB) homopolymer 18,24,26,[31][32][33] , and these crystals, which consist of stacks of lamellae, have variable thickness. Furthermore, in case of P(3HB-co-8%-3HH) and P(3HB-co-10%-4HB), their single crystals showed a lath-shaped morphology 47) . Each monolamellar part of lath-shaped copolymer single crystals yields a sharp electron diffraction pattern, and this diffraction pattern is consistent with a p 2gg symmetry, which coincides with that of P(3HB) single crystals 11,12,33) .…”

Section: Poly([r]-3-hydroxybutyrate) Copolymersmentioning

confidence: 96%

“…These results suggest that the splintering phenomenon along the crystallographic a axis of single crystal is a widespread effect of extracellular PHB depolymerase. Furthermore, all of P(3HB) copolymer single crystals were degraded from crystal edges for generating the splintering phenomenon, in spite of the different of surface morphology 13,47) .…”

Section: Poly([r]-3-hydroxybutyrate) and Its Copolymersmentioning

confidence: 99%

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Crystal structure and biodegradation of aliphatic polyester crystals

Iwata¹,

Doi

1999

Macromol. Chem. Phys.

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140

121

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SUMMARY: The biodegradability of aliphatic polyesters, which are produced by biosynthesis and chemosynthesis, strongly correlates to the polymer morphology such as crystallinity, molecular orientation, chain packing and crystal surface, in addition to the chemical structure. For elucidation of biodegradation mechanism of crystal regions on an atomic level, lamellar single crystals of poly([R]-3-hydroxybutyrate) (P(3HB)) and its copolymers, poly([R]-3-hydroxyvalerate) (P(3HV)), poly(4-hydroxybutyrate) (P(4HB)), poly(L-lactic acid) (PLLA) and poly(ethylene succinate) (PES) were prepared from dilute solution by isothermal crystallization, and the crystal structures and morphologies were investigated by means of mainly transmission electron microscopy and atomic force microscopy. All single crystals were intramolecular single crystals, with spiral growth in some cases, and these crystals gave well-resolved electron diffractograms. The enzymatic degradation of lamellar crystals of P(3HB) and its copolymers was carried out with extracellular PHB depolymerases, and it was revealed that enzymatic degradation of lamellar crystals progressed from crystal edges and ends rather than the chain-folding surfaces of crystals, in spite of the homogeneous adsorption of enzyme molecules on the crystal surfaces by substrate-binding domain. Furthermore, in the case of PLLA single crystals, single crystals were also degraded from the edges to yield a rounded shape without decreasing the molecular weights and lamellar thickness. These results suggest that the attack by the active site of enzyme takes place at disordered regions of the crystals, that is, disordered lateral sites with high mobility of molecular chains are preferentially degraded.

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Section: Poly([r]-3-hydroxybutyrate) Copolymersmentioning

confidence: 96%

Section: Poly([r]-3-hydroxybutyrate) and Its Copolymersmentioning

confidence: 99%

Crystal structure and biodegradation of aliphatic polyester crystals

Iwata¹,

Doi

1999

Macromol. Chem. Phys.

Self Cite

140

121

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“…Castela [35] and Iwata [36], on the other hand, separated the components of the aqueous medium chromatographically and then analyzed the metabolites quantitatively. However, usually more effective detection techniques are needed to solve these problems.…”

Section: Introductionmentioning

confidence: 99%

The novel technique of vapor pressure analysis to monitor the enzymatic degradation of PHB by HPLC chromatography

Polyák

Rácz

Rózsa

et al. 2017

Analytical Biochemistry

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“…Poly[(R)-hydroxybutyrate-co-hydroxyhexanoate] (PHBHx) is a Nodax TM series commercial biodegradable plastic, for which large-scale industrial production has been reported (Chen et al 2001). Studies of enzymatic degradation of PHBHx have been conducted (Iwata et al 1999;Kikkawa et al 2002;Li et al 2007), although to our knowledge, systematic studies on whole cell microbial degradation of this polymer under diverse conditions have been very limited.…”

Section: Introductionmentioning

confidence: 99%

Microbial degradation and physico-chemical alteration of polyhydroxyalkanoates by a thermophilic Streptomyces sp.

et al. 2009

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A thermophilic Streptomyces sp. capable of degrading various aliphatic polyesters was isolated from a landfill site. The isolate, Streptomyces sp. BCC23167, demonstrated rapid aerobic degradation of several polyesters, including polyhydroxyalkanoate copolymers, poly(ε-caprolactone) and polybutylene succinate at 50• C and neutral pH. The degrading activity was repressed by glucose and cellobiose, but tolerant to repression by other carbon substrates. Degradation of a commercial poly[(R)-3-hydroxybutyrate-co-3-hydroxyhexanoate] (PHBHx) by Streptomyces sp. BCC23167 progressed from surface to bulk as suggested by the slight decrease in polymer molecular weight. Differential scanning calorimetry analysis of PHBHx film degradation by Streptomyces sp. BCC23167 showed that relative crystallinity of the film increased slightly in the early stage of degradation, followed by a marked decrease later on. The surface morphology of degraded films was analyzed by scanning electron microscopy, which showed altered surface structure consistent with the changes in crystallinity. The isolate is thus of potential for application in composting technology for bio-plastic degradation.

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Structure and enzymatic degradation of poly(3-hydroxybutyrate) copolymer single crystals with an extracellular PHB depolymerase from Alcaligenes faecalis T1

Cited by 75 publications

References 42 publications

Crystal structure and biodegradation of aliphatic polyester crystals

Crystal structure and biodegradation of aliphatic polyester crystals

The novel technique of vapor pressure analysis to monitor the enzymatic degradation of PHB by HPLC chromatography

Microbial degradation and physico-chemical alteration of polyhydroxyalkanoates by a thermophilic Streptomyces sp.

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