The Experts below are selected from a list of 642 Experts worldwide ranked by ideXlab platform
Fabrice Leroux - One of the best experts on this subject based on the ideXlab platform.
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chain extender effect of 3 4 hydroxyphenyl propionic acid layered double hydroxide in Biopolyesters containing the succinate moiety
New Journal of Chemistry, 2020Co-Authors: Laura Sisti, Grazia Totaro, Annamaria Celli, Vincent Verney, Adam A Marek, Fabrice LerouxAbstract:3-(4-Hydroxyphenyl)propionic acid intercalated in Mg2Al/layered double hydroxide has been used as a filler in Biopolyesters containing the succinate moiety, such as poly(propylene succinate) (PPS), poly(butylene succinate-co-butylene adipate) (PBSA) and poly(butylene succinate) (PBS), with the aim of inducing an effect similar to that of an increment of the molecular weight of the matrices. The composites (1, 5 and 10 wt% of filler) have been prepared by a simple melt blending procedure. X-ray diffraction analysis revealed the presence of intercalated structures in the composites. From melt rheology measurements, a chain extender effect of the filler, towards PBS, PPS and to some extent PBSA, was evident and proportional to the composition, producing a reinforcing role of the filler towards the polymeric chains. Moreover, no gel-like structure was produced. Such findings can be useful in widening the processing window of Biopolyesters, in order to design multifunctional materials with adapted properties.
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Chain extender effect of 3-(4-hydroxyphenyl)propionic acid/layered double hydroxide in Biopolyesters containing the succinate moiety
New Journal of Chemistry, 2020Co-Authors: Laura Sisti, Grazia Totaro, Annamaria Celli, Adam Marek, Vincent Verney, Fabrice LerouxAbstract:3-(4-Hydroxyphenyl)propionic acid intercalated in Mg2Al/layered double hydroxide has been used as a filler in Biopolyesters containing the succinate moiety, such as poly(propylene succinate) (PPS), poly(butylene succinate-co-butylene adipate) (PBSA) and poly(butylene succinate) (PBS), with the aim of inducing an effect similar to that of an increment of the molecular weight of the matrices. The composites (1, 5 and 10 wt% of filler) have been prepared by a simple melt blending procedure. X-ray diffraction analysis revealed the presence of intercalated structures in the composites. From melt rheology measurements, a chain extender effect of the filler, towards PBS, PPS and to some extent PBSA, was evident and proportional to the composition, producing a reinforcing role of the filler towards the polymeric chains. Moreover, no gel-like structure was produced. Such findings can be useful in widening the processing window of Biopolyesters, in order to design multifunctional materials with adapted properties.
Ch V Ramana - One of the best experts on this subject based on the ideXlab platform.
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biotechnological potentials of anoxygenic phototrophic bacteria i production of single cell protein vitamins ubiquinones hormones and enzymes and use in waste treatment
Advances in Applied Microbiology, 1995Co-Authors: Ch Sasikala, Ch V RamanaAbstract:Publisher Summary Biotechnology, which is being studied globally for possible practical exploitation, can provide economical and efficient solutions for the problems addressed in detail. The advantages of anoxygenic phototrophic bacteria include metabolic versatility which makes it possible to grow them by various growth modes including photo- and chemoautotrophy, heterotrophy, and fermentation, coupled to high growth rates and easy manipulation. The chapter explores that, as light is the source of energy, these bacteria can prove highly beneficial for industrial applications similar to those for which microalgae are already being used in the field of biotechnology and microbiology. In addition, the chapter also discusses the use in waste treatments. Apart from those uses discussed in this chapter, anoxygenic phototrophic bacteria can be used in the production of Biopolyesters, fuel (hydrogen), insecticides, along with their potential use as biofertilizers.
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biotechnological potentials of anoxygenic phototrophic bacteria ii Biopolyesters biopesticide biofuel and biofertilizer
Advances in Applied Microbiology, 1995Co-Authors: Ch Sasikala, Ch V RamanaAbstract:Publisher Summary This chapter discusses the biotechnological potentials of anoxygenic phototrophic bacteria II. There is an increasing demand for the use of plasticized (polyester) materials suitable for human needs and many of them which are currently being synthesized chemically are nonbiodegradable and, hence, ecologically not ideal. There is an immediate requirement to replace the nonbiodegradable polyesters by a natural and biodegradable polyester, a waste management option for polymers in the environment, and, in many cases, the demand is driven by legislation. Studies with a number of isolates of anoxygenic phototrophic bacteria suggest that PHA formation is a common phenomenon among this group of microorganisms. In addition, Poly -β -hydroxybutyrate (PHB) is the best-known member of the PHA series of polyesters and it is known to be produced as intracellular energy and carbon reserves which are later utilized by the bacteria for cellular growth.
Andreia F Sousa - One of the best experts on this subject based on the ideXlab platform.
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ex situ reconstitution of the plant biopolyester suberin as a film
Biomacromolecules, 2014Co-Authors: Helga Garcia, Andreia F Sousa, Armando J D Silvestre, Celso Martins, Rui Cruz Ferreira, Carmen S R Freire, Luis Paulo N Rebelo, Werner Kunz, Cristina Silva PereiraAbstract:Biopolymers often have unique properties of considerable interest as a basis for new materials. It is however not evident how to extract them from plants without destroying their chemical skeleton and inherent properties. Here we report the ex situ reconstitution of the biopolyester suberin as a new waterproof and antimicrobial material. In plant cell walls, suberin, a cross-linked network of aromatic and aliphatic monomers, builds up a hydrophobic protective and antimicrobial barrier. Recently we succeeded in extracting suberin from the plant cell wall using the ionic liquid cholinium hexanoate. During extraction the native three-dimensional structure of suberin was partially preserved. In this study, we demonstrate that this preservation is the key for its ex situ reconstitution. Without any chemical additives or purification, the suberin composing macromolecules undergo self-association on the casting surface forming a film. Suberin films obtained show barrier properties similar to those of the suberin...
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novel suberin based Biopolyesters from synthesis to properties
Journal of Polymer Science Part A, 2011Co-Authors: Andreia F Sousa, Armando J D Silvestre, Carlos Pascoal Neto, Alessandro Gandini, Jose Cruz J C Pinto, Christer Eckerman, Bjarne HolmbomAbstract:This article reports the successful synthesis and characterization of two types of completely biobased poly- mers prepared by the polycondensation or polytransesterifi- cation of suberin fragments, isolated by different procedures and from two different vegetable sources. These polymeriza- tions were conducted with different experimental conditions in terms of the type of catalyst, the reaction medium and temperature, as well as the molar ratio between the reactive moieties. The ensuing linear or partly crosslinked polyesters were characterized by conventional spectroscopic techni- ques, SEC, DSC, XRD, DMA, and TGA. These hydrophobic materials represent an original contribution to the growing field of polymers from renewable resources. V C 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2281- 2291, 2011
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synthesis and characterization of novel Biopolyesters from suberin and model comonomers
Chemsuschem, 2008Co-Authors: Andreia F Sousa, Armando J D Silvestre, Alessandro Gandini, Carlos Pascoal NetoAbstract:The synthesis of novel polyesters from model long-chain aliphatic monomers and from suberin reactive aliphatic fragments was conducted using mild polycondensation or polytransesterification conditions. The ensuing polyesters were characterized by means of various techniques. When mixtures of simple suberin-like monomers were used, the ensuing polyesters had very regular structures, with melting temperatures around 80 degrees C and glass transitions below room temperature. This first systematic study of the exploitation of suberin as a precursor to novel aliphatic polyesters confirmed the huge potential of using this abundant renewable resource to prepare macromolecular materials for promising applications.
Laura Sisti - One of the best experts on this subject based on the ideXlab platform.
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chain extender effect of 3 4 hydroxyphenyl propionic acid layered double hydroxide in Biopolyesters containing the succinate moiety
New Journal of Chemistry, 2020Co-Authors: Laura Sisti, Grazia Totaro, Annamaria Celli, Vincent Verney, Adam A Marek, Fabrice LerouxAbstract:3-(4-Hydroxyphenyl)propionic acid intercalated in Mg2Al/layered double hydroxide has been used as a filler in Biopolyesters containing the succinate moiety, such as poly(propylene succinate) (PPS), poly(butylene succinate-co-butylene adipate) (PBSA) and poly(butylene succinate) (PBS), with the aim of inducing an effect similar to that of an increment of the molecular weight of the matrices. The composites (1, 5 and 10 wt% of filler) have been prepared by a simple melt blending procedure. X-ray diffraction analysis revealed the presence of intercalated structures in the composites. From melt rheology measurements, a chain extender effect of the filler, towards PBS, PPS and to some extent PBSA, was evident and proportional to the composition, producing a reinforcing role of the filler towards the polymeric chains. Moreover, no gel-like structure was produced. Such findings can be useful in widening the processing window of Biopolyesters, in order to design multifunctional materials with adapted properties.
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Chain extender effect of 3-(4-hydroxyphenyl)propionic acid/layered double hydroxide in Biopolyesters containing the succinate moiety
New Journal of Chemistry, 2020Co-Authors: Laura Sisti, Grazia Totaro, Annamaria Celli, Adam Marek, Vincent Verney, Fabrice LerouxAbstract:3-(4-Hydroxyphenyl)propionic acid intercalated in Mg2Al/layered double hydroxide has been used as a filler in Biopolyesters containing the succinate moiety, such as poly(propylene succinate) (PPS), poly(butylene succinate-co-butylene adipate) (PBSA) and poly(butylene succinate) (PBS), with the aim of inducing an effect similar to that of an increment of the molecular weight of the matrices. The composites (1, 5 and 10 wt% of filler) have been prepared by a simple melt blending procedure. X-ray diffraction analysis revealed the presence of intercalated structures in the composites. From melt rheology measurements, a chain extender effect of the filler, towards PBS, PPS and to some extent PBSA, was evident and proportional to the composition, producing a reinforcing role of the filler towards the polymeric chains. Moreover, no gel-like structure was produced. Such findings can be useful in widening the processing window of Biopolyesters, in order to design multifunctional materials with adapted properties.
Guo Qiang Chen - One of the best experts on this subject based on the ideXlab platform.
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polyhydroxyalkanoates pha for therapeutic applications
Materials Science and Engineering: C, 2018Co-Authors: Junyu Zhang, T. G. Volova, Ekaterina I Shishatskaya, Luiziana Ferreira Da Silva, Guo Qiang ChenAbstract:As intracellular carbon and energy storage materials, polyhydroxyalkanoates (PHA) are a diverse Biopolyesters synthesized by many bacteria. PHA have been produced in large quantity for various application research including medical implants for approximately 30years. Many studies demonstrated that PHA are promising implant materials due to their diverse and ascendant mechanical, biodegradable and tissue compatible properties. Importantly, common PHA biodegradation products including oligomers and monomers are also not toxic to the cells and tissues. Pharmaceutical applications of some PHA degradation products also have been reported. So far, no study has been reported to have any carcinogenesis result induced by any PHA or their biodegradation products. All results suggest that PHA could be developed into various bio-implant products.
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suspended polyhydroxyalkanoate microspheres as 3d carriers for mammalian cell growth
Artificial Cells Nanomedicine and Biotechnology, 2018Co-Authors: Daixu Wei, Jinwei Dao, Huawei Liu, Guo Qiang ChenAbstract:Different forms of biopolyester PHBVHHx microspheres were prepared so as to compare the mammalian cell behaviors in suspension cultivation system. Based on a microbial terpolyester PHBVHHx consisti...
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microbial polyhydroxyalkanoates as medical implant biomaterials
Artificial Cells Nanomedicine and Biotechnology, 2018Co-Authors: Guo Qiang Chen, Junyu ZhangAbstract:Polyhydroxyalkanoates (PHAs), a diverse biopolyester synthesized by many bacteria as intracellular carbon and energy storage materials, have been produced in large quantity for various application researches including medical implants for approximately 30 years. It has been demonstrated by many studies that PHAs possess the required mechanical, biodegradable and tissue-compatible properties for implant applications. Very importantly, common PHA biodegradation products including oligomers and monomers are also not toxic to the cells and tissues. Some PHA degradation products have been studied for pharmaceutical applications. Mechanisms of PHA that stimulate cell growth were revealed. So far, no study has been reported to have any carcinogenesis result induced by any PHA or their biodegradation products. All results point to the feasibility of PHA to be developed into various bio-implant products.
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engineering biosynthesis mechanisms for diversifying polyhydroxyalkanoates
Trends in Biotechnology, 2015Co-Authors: Guo Qiang Chen, Ivan HajnalAbstract:Polyhydroxyalkanoates (PHA) are a family of diverse Biopolyesters synthesized by bacteria. PHA diversity, as reflected by its monomers, homopolymers, random and block copolymers, as well as functional polymers, can now be generated by engineering the three basic synthesis pathways including the acetoacetyl-CoA pathway, in situ fatty acid synthesis, and/or β-oxidation cycles, as well as PHA synthase specificity. It is now possible to tailor the PHA structures via genome editing or process engineering. The increasing PHA diversity and maturing PHA production technology should lead to more focused research into their low-cost and/or high-value applications.
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medical applications of Biopolyesters polyhydroxyalkanoates
Chinese Journal of Polymer Science, 2013Co-Authors: Guo Qiang Chen, Yang WangAbstract:Microbial polyhydroxyalkanoates (PHAs) are a family of Biopolyesters produced by many wild type and engineered bacteria. PHAs have diverse structures accompanied by flexible thermal and mechanical properties. Combined with their in vitro biodegradation, cell and tissue compatibility, PHAs have been studied for medical applications, especially medical implants applications, including heart valve tissue engineering, vascular tissue engineering, bone tissue engineering, cartilage tissue engineering, nerve conduit tissue engineering as well as esophagus tissue engineering. Most studies have been conducted in the authors’ lab in the past 20+ years. Recently, mechanism on PHA promoted tissue regeneration was revealed to relate to cell responses to PHA biodegradation products and cell-material interactions mediated by microRNA. Very importantly, PHA implants were found not to cause carcinogenesis during long-term implantation. Thus, PHAs should have a bright future in biomedical areas.