Evaluation of the Highly Ordered Structure, Ligature, and Enzymatic Degradation of Poly[()-3-hydroxybutyrate--4-hydroxybutyrate] Elastic Porous Fibers.

We prepared biocompatible elastic fibers with high porosity and high tensile strength from poly[()-3-hydroxybutyrate--4-hydroxybutyrate], which is a microbial polyester that can be produced from renewable carbon resources by isothermal crystallization. It was possible to control the pore size by adjusting the isothermal crystallization time. Most of the pores were approximately less than 10 μm in diameter, did not penetrate, and were distributed discontinuously throughout the fibers.

Coastal and deep-sea biodegradation of polyhydroxyalkanoate microbeads.

Microbeads find widespread usage in personal care items and cosmetics, serving as exfoliants or scrubbing agents. Their micro-scale size poses challenges in effective drainage capture and given their origin from non-biodegradable oil-based plastics, this contributes substantially to marine pollution. In this study, microbeads were prepared by a simple yet scalable melt homogenization method using four types of polyhydroxyalkanoates (PHA), namely poly[(R)-3-hydroxybutyrate] (P(3HB)), poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] (P(3HB-co-3HV)), poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] (P(3HB-co-3HHx)) and poly[(R)-3-hydroxybutyrate-co-(R)-4-hydroxyvalerate] (P(3HB-co-4HB)).

Recyclable Polycarbosilane from a Biomass-Derived Bifuran-Based Monomer.

Two of the most fundamental principles for the development of next-generation polymers are production from renewable biomass and well-designed recyclability. Bifuran derivatives represent promising building blocks for functional polymers on account of their high rigidity, strong interchain interactions, and extended π-conjugation. In this study, a polycarbosilane containing a bifuran-based repeat unit was prepared via the hydrosilylation of dihydrosilylbifuran and 1,5-hexadiene.

Environmental biodegradability of recombinant structural protein.

Next generation polymers needs to be produced from renewable sources and to be converted into inorganic compounds in the natural environment at the end of life. Recombinant structural protein is a promising alternative to conventional engineering plastics due to its good thermal and mechanical properties, its production from biomass, and its potential for biodegradability. Herein, we measured the thermal and mechanical properties of the recombinant structural protein BP1 and evaluated its biodegradability.

Biobased Poly(Schiff-Base) Composed of Bifurfural.

In this study, bifurfural, an inedible biobased chemical and a second-generation biomass, was polymerized with several diamines using an environmentally benign process, and the chemical structures of the resulting poly(Schiff base)s were analyzed. Because furan rings, which are only produced from biomass and not from fossil resources, endow polymers with unique properties that include high rigidity and expanded π-conjugation, bifurfural, which contains two furan rings, is of significant interest as a biobased building block. H NMR, IR, and matrix assisted laser desorption ionization-time of flight mass spectra of the poly(Schiff base)s reveal that they are composed of mixtures of linear and cyclic structures.

Synthesis and verification of biobased terephthalic acid from furfural.

Exploiting biomass as an alternative to petrochemicals for the production of commodity plastics is vitally important if we are to become a more sustainable society. Here, we report a synthetic route for the production of terephthalic acid (TPA), the monomer of the widely used thermoplastic polymer poly(ethylene terephthalate) (PET), from the biomass-derived starting material furfural. Biobased furfural was oxidised and dehydrated to give maleic anhydride, which was further reacted with biobased furan to give its Diels-Alder (DA) adduct.

Crystalline-structure-dependent enzymatic degradation of polymorphic poly(3-hydroxypropionate).

The crystalline structure dependence of enzymatic degradation behavior was investigated for the polymorphic poly(3-hydroxypropionate) (P3HP), which has a basic backbone chemical structure of bacterial poly(3-hydroxyalkanoate)s (P3HAs). The P3HP films consisting of the beta-, gamma-, and/or delta-form crystal were cast or melt-crystallized as reported previously (Macromolecules 2005, 38, 6455; Macromolecules 2006, 39, 194-203) by controlling the molecular weight, crystallization temperature, and/or temperature of the melt. Their thermal properties, crystalline structures, morphologies, and (13)C solid spin-lattice relaxation dynamics were characterized by the differential scanning calorimetry, the wide-angle X-ray diffraction, the small-angle X-ray scattering (SAXS), and the (13)C solid-state NMR spectra (SNMR), respectively.

Fine structure and enzymatic degradation of poly[(R)-3-hydroxybutyrate] and stereocomplexed poly(lactide) nanofibers.

Fiber morphology and crystalline structure of poly[(R)-3-hydroxybutyrate] (P(3HB)) and stereocomplexed poly(lactide) (PLA) nanofibers were investigated by using scanning and transmission electron microscopies and X-ray and electron diffractions. In the P(3HB) nanofibers spun from less than 1 wt% 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solution, planar zigzag conformation (beta-form) as well as 2(1) helix conformation (alpha-form) structure was formed. Based on the electron diffraction measurement of single P(3HB) nanofiber, it was revealed that the molecular chains of P(3HB) align parallel to the fiber direction.

Adsorption and hydrolysis reactions of poly(hydroxybutyric acid) depolymerases secreted from Ralstonia pickettii T1 and Penicillium funiculosum onto poly[(R)-3-hydroxybutyric acid].

Reaction processes of poly[(R)-3-hydroxybutyric acid] (P(3HB)) with two types of poly(hydroxybutyric acid) (PHB) depolymerases secreted from Ralstonia pickettii T1 and Penicillium funiculosum were characterized by means of atomic force microscopy (AFM) and quartz crystal microbalance (QCM). The PHB depolymerase from R. pickettii T1 consists of catalytic, linker, and substrate-binding domains, whereas the one from P.

The crystal structure of polyhydroxybutyrate depolymerase from Penicillium funiculosum provides insights into the recognition and degradation of biopolyesters.

Polyhydroxybutyrate is a microbial polyester that can be produced from renewable resources, and is degraded by the enzyme polyhydroxybutyrate depolymerase. The crystal structures of polyhydroxybutyrate depolymerase from Penicillium funiculosum and its S39 A mutant complexed with the methyl ester of a trimer substrate of (R)-3-hydroxybutyrate have been determined at resolutions of 1.71 A and 1.

Correlation between solid-state structures and enzymatic degradability of cocrystallized blends.

Solid-state structures and enzymatic degradability have been investigated for cocrystallized blends between poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [PHBV] and poly(3-hydroxybutyrate-co-3-hydroxypropionate) [PHBP]. From wide-angle X-ray diffraction patterns, small-angle X-ray scattering data, and the comparison of the enzymatic degradability of these blends, the solid-state structures of PHBV/PHBP blend samples, in which the PHBV component has higher isothermal crystal growth rate (G) value than the PHBP one, might be similar to those of the component PHBVs; while those of the PHBP/PHBV blend samples, in which PHBP component has higher G value, were similar to the component PHBPs. Normalized one-dimensional correlation functions gamma(x) of PHBV/PHBP binary blends crystallized at 90 degrees C.

Cloning, expression and characterization of a poly(3-hydroxybutyrate) depolymerase from Marinobacter sp. NK-1.

A DNA fragment carrying the gene encoding poly(3-hydroxybutyrate) (P(3HB)) depolymerase was cloned from the genomic DNA of Marinobacter sp. DNA sequencing analysis revealed that the Marinobacter sp. P(3HB) depolymerase gene is composed of 1734bp and encodes 578 amino acids with a molecular mass of 61,757Da.

Change of surface structure of poly(3-hydroxybutyrate) film upon enzymatic hydrolysis by PHB depolymerase.

The change in the surface structure of poly[(R)-3-hydroxybutyrate] [PHB] films upon the enzymatic hydrolysis was analyzed by attenuated total reflection infrared [ATR/IR] spectrometry. As enzymes, PHB depolymerases isolated from Ralstonia pickettii T1 and Pseudomonas stutzeri were used. By curve decomposition of the carbonyl stretching band of ATR/IR spectra, the change in the surface crystallinity of PHB films by exposure to buffer containing 0, 1, and 4 microg of PHB depolymerases was estimated.

Enzymatic hydrolysis of chemosynthesized atactic poly(3-hydroxybutyrate) by poly(3-hydroxyalkanoate) depolymerase from Acidovorax Sp. TP4 and Ralstonia pickettii T1.

The enzymatic degradability of chemosynthesized atactic poly([R,S]-3-hydroxybutyrate) [a-P(3HB)] by two types of extracellular poly(3-hydroxyalkanoate) (PHA) depolymerases purified from Ralstonia pickettii T1 (PhaZ(ral)) and Acidovorax Sp. TP4 (PhaZ(aci)), defined respectively as PHA depolymerase types I and II according to the position of the lipase box in the catalytic domain, were studied. The enzymatic degradation of a-P(3HB) by PhaZ(aci) depolymerase was confirmed from the results of weight loss and the scanning electron micrographs.

Enzymatic hydrolysis of bacterial poly(3-hydroxybutyrate-co-3-hydroxypropionate)s by poly(3-hydroxyalkanoate) depolymerase from Acidovorax Sp. TP4.

Enzymatic degradability has been investigated for a series of bacterial poly(3-hydroxybutyrate-co-3-hydroxypropionate)s (P(3HB-co-3HP)s) with 3-hydroxypropionate (3HP) unit contents from 11 to 86 mol % as well as poly(3-hydroxybutyrate) (P(3HB)) and chemosynthesized poly(3-hydroxypropionate) (P(3HP)). The behavior of degradation by two types of extracellular poly(3-hydroxyalkanoate) (PHA) depolymerases purified from Ralstonia pikettii T1 and Acidovorax Sp. TP4, defined respectively as PHA depolymerase types I and II according to the position of the lipase box in the catalytic domain, were compared in relation to the thermal properties and crystalline structures of the PHA samples elucidated by differential scanning calorimetry and wide-angle X-ray diffraction.