The chemomechanical properties of microbial polyhydroxyalkanoates

Laycock, Bronwyn; Halley, P. J.; Pratt, Steven; Werker, Alan; Lant, Paul

doi:10.1016/j.progpolymsci.2012.06.003

Cited by 395 publications

(272 citation statements)

References 372 publications

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“…PHB is apparently produced by microorganisms (such as Ralstonia eutrophus or Bacillus megaterium) in response to conditions of physiological stress and can be produced either by pure culture than mixed culture of bacteria [11]. The polymer is primarily a product of carbon assimilation (from glucose or starch) and is employed by microorganisms as a form of energy storage molecule to be metabolized when other common energy sources are not available.…”

Section: Polyhydroxyalkanoate Polymersmentioning

confidence: 99%

Polyhydroxyalkanoate (PHA): Review of synthesis, characteristics, processing and potential applications in packaging

Bugnicourt¹,

Cinelli²,

Lazzeri³

et al. 2014

Express Polym. Lett.

721

463

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Abstract. Polyhydroxyalkanoates (PHAs) are gaining increasing attention in the biodegradable polymer market due to their promising properties such as high biodegradability in different environments, not just in composting plants, and processing versatility. Indeed among biopolymers, these biogenic polyesters represent a potential sustainable replacement for fossil fuel-based thermoplastics. Most commercially available PHAs are obtained with pure microbial cultures grown on renewable feedstocks (i.e. glucose) under sterile conditions but recent research studies focus on the use of wastes as growth media. PHA can be extracted from the bacteria cell and then formulated and processed by extrusion for production of rigid and flexible plastic suitable not just for the most assessed medical applications but also considered for applications including packaging, moulded goods, paper coatings, non-woven fabrics, adhesives, films and performance additives. The present paper reviews the different classes of PHAs, their main properties, processing aspects, commercially available ones, as well as limitations and related improvements being researched, with specific focus on potential applications of PHAs in packaging.

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Section: Polyhydroxyalkanoate Polymersmentioning

confidence: 99%

Polyhydroxyalkanoate (PHA): Review of synthesis, characteristics, processing and potential applications in packaging

Bugnicourt¹,

Cinelli²,

Lazzeri³

et al. 2014

Express Polym. Lett.

721

463

View full text Add to dashboard Cite

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“…Another frequently used polymer from polyhydroxyalkanoate family mixed with PLA is poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV). Its properties are known to depend on hydroxyvalerate (HV) content [10]. At very low HV content, PHBV is similar to conventional petrochemical thermoplastics, such as polypropylene, in terms of melting temperature, crystallinity, and tensile strength [11][12][13][14][15].…”

mentioning

confidence: 99%

Polylactide/poly(hydroxybutyrate-co-hydroxyvalerate) blends: Morphology and mechanical properties

Gérard¹,

Budtova²,

Podshivalov³

et al. 2014

Express Polym. Lett.

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International audienceThe morphology and the mechanical properties of polylactide/poly(hydroxybutyrate-co-hydroxyvalerate) blends of various compositions were studied. The statistical analysis of the scanning electron microscopy images allowed finding two statistical ensembles of the minor-phase particles. The first ensemble involves the dispersed particles, whereas the second one contains the coalesced particles. The mean diameters of both dispersed and coalesced minor-phase particles were calculated and plotted against the blend composition. Young's modulus, tensile strength, elongation at break, and Charpy impact strength of the blends were determined and examined as a function of the blend composition. The Young's modulus values were shown to be in accordance with theoretical predictions

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“…4 Vale ressaltar que, na maioria das vezes, esse polímero biodegradável é produzido em condições não balanceadas pela limitação de algum nutriente (como fósforo e nitrogênio) e rico na fonte de carbono.…”

Section: Introductionunclassified

“…3 Cerca de 150 monômeros diferentes já foram identificados como constituintes de PHAs produzidos por bactérias a partir de diversas fontes de carbono. 4 Vale ressaltar que, na maioria das vezes, esse polímero biodegradável é produzido em condições não balanceadas pela limitação de algum nutriente (como fósforo e nitrogênio) e rico na fonte de carbono. 5 Cupriavidus necator (também conhecida como Wautersia eutropha, Ralstonia eutropha e Alcaligenes eutrophus) é a espécie bacteriana mais estudada na produção desses biopolímeros, 6 mas a busca por outros isolados em amostras ambientais diversas que favoreçam o mesmo tem se intensificado.…”

Section: Introductionunclassified

“…Do ponto de vista econômico, embora os PHAs apresentem vantagens ambientais sobre os plásticos de origem petroquímica, seu alto custo de produção, em especial com utilização de fontes de carbono puras, e também de metodologias de extração, ainda limita a aplicação comercial. 4 Por isso, a busca de substratos ricos em carbono, de baixo custo, e que agreguem a remoção de resíduos poluentes do ambiente, tem aumentado. Diversas pesquisas destacam o uso de melaço e caldo-de-cana.…”

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Poliphasic Screening of Polyhydroxyalkanoate-Producing Microorganisms

Silva¹,

Santos²,

Santos³

et al. 2016

Química Nova

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publicado na web em 10/05/2016 POLIPHASIC SCREENING OF POLYHYDROXYALKANOATE-PRODUCING MICROORGANISMS. Polyhydroxyalkanoates (PHAs) are fully biodegradable biopolyesters produced by many prokaryotes and accumulated as insoluble cytoplasmatic inclusions. The detection of these intracellular granule is usually provided using lipofilic azodyes, which are not specific. Another way to screen PHA-producing bacteria is through culture-independent molecular techniques such Polymerase Chain Reaction (PCR), and the search for new PHA-producer strains is essential to reduce the cost at industrial level. The application of these both methods is desirable. In the present study, 24 bacteria isolated from soil of the Atlantic forest in Maceió (AL, Brazil) and from agri-industrial sludge (Coruripe-AL, Brazil) were studied regarding to their capacity of growing in mineral salt medium, as indicative of PHA synthesis. All strains were submitted to biochemical characterization, whilst PCR has proved that isolates BMA-05, BMA-10, BMA-13 and BDL-07 has the gene phaC, which encodes a PHA synthase, the key for PHA synthesis. The amplification and sequencing of their 16S r-DNA region was able to identify these bacteria respectively as Pseudomonas fluorescens, Enterobacter aerogenes, Klebsiella oxytoca and Bacillus pumilus. The same minimal medium supplement with peptone demonstrated to induce growing of those strains.Keywords: polyhydroxyalkanoate; molecular identification; PhaC synthase. INTRODUÇÃOPara ser considerado um plástico degradável, a molécula deve apresentar cadeia com ou sem ramificação ou com grupos funcionais éster, amida ou acetal.1 Comumente, tais características não são atendidas pelos polímeros sintéticos, e sua degradação no ambiente dá-se muito lentamente. Por outro lado, os plásticos denominados biodegradáveis possuem os requisitos apresentados para tal e por isso são rapidamente decompostos por muitas espécies bacterianas e microalgas. Conforme descrito por Khanna e Srivastava, 2 distribuem-se em três categorias: a) a dos polímeros sintéticos suscetíveis a degradação e/ou ataque enzimático de microrganismos, mas que não atendem a todas as características necessárias para exploração comercial; b) a dos bioplásticos baseados no polissacarídeo amido, que são parcialmente degradáveis, pois os microrganismos degradam o amido mas não o polímero sintético que faz parte da composição desses produtos; c) a dos polihidroxialcanoatos (PHAs) produzidos por diversos microrganismos e armazenados intracelularmente como inclusões amorfas, mas que são totalmente degradáveis por organismos vivos.Nesse sentido, desde a década de 90 do século passado, o Brasil vem dedicando um considerável esforço para o desenvolvimento de processos visando a geração em larga escala e utilização de polihidroxialcanoatos (PHAs) em produtos.3 Cerca de 150 monômeros diferentes já foram identificados como constituintes de PHAs produzidos por bactérias a partir de diversas fontes de carbono. 4 Vale ressaltar que, na maioria das vezes, esse polímero biodegra...

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The chemomechanical properties of microbial polyhydroxyalkanoates

Cited by 395 publications

References 372 publications

Polyhydroxyalkanoate (PHA): Review of synthesis, characteristics, processing and potential applications in packaging

Polyhydroxyalkanoate (PHA): Review of synthesis, characteristics, processing and potential applications in packaging

Polylactide/poly(hydroxybutyrate-co-hydroxyvalerate) blends: Morphology and mechanical properties

Poliphasic Screening of Polyhydroxyalkanoate-Producing Microorganisms

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