Статті в журналах: "Biopolymers characterisation"

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John, Maya Jacob, Nokuzola Dyanti, Teboho Mokhena, Victor Agbakoba, and Bruce Sithole. "Design and Development of Cellulosic Bionanocomposites from Forestry Waste Residues for 3D Printing Applications." Materials 14, no. 13 (June 22, 2021): 3462. http://dx.doi.org/10.3390/ma14133462.

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This paper deals with the development of cellulose nanofibres (CNFs) reinforced biopolymers for use in packaging applications. Cellulose nanofibres were extracted from sawdust by a combination of chemical and mechanical treatments. The extracted cellulose nanofibres were chemically modified (fCNFs) and characterised by Fourier Transform Infrared Spectroscopy (FTIR). Bionanocomposites were prepared from biopolymers polylactic acid/polybutylene succinate (PLA/PBS) and cellulose nanofibres by compounding in a twin-screw extruder followed by injection moulding. The developed bionanocomposites were subjected to mechanical and thermal characterisation. As part of product development, CNF-biopolymer pellets were also extruded into filaments which were then 3D printed into prototypes. This work is a successful demonstration of conversion of waste residues into value-added products, which is aligned to the principles of circular economy and sustainable development.

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Oyekanmi, Adeleke A., N. I. Saharudin, Che Mohamad Hazwan, Abdul Khalil H. P. S., Niyi G. Olaiya, Che K. Abdullah, Tata Alfatah, Deepu A. Gopakumar, and Daniel Pasquini. "Improved Hydrophobicity of Macroalgae Biopolymer Film Incorporated with Kenaf Derived CNF Using Silane Coupling Agent." Molecules 26, no. 8 (April 13, 2021): 2254. http://dx.doi.org/10.3390/molecules26082254.

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Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films’ modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.

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Gauthier, Emilie, Diane Ouwerkerk, Bronwyn Laycock, and Mary Fletcher. "Biopolymer Composites for Slow Release to Manage Pimelea Poisoning in Cattle." Proceedings 36, no. 1 (February 13, 2020): 97. http://dx.doi.org/10.3390/proceedings2019036097.

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Cattle grazing the pastures of inland Australia can be poisoned by ingestion of certain native Pimelea plant species, particularly Pimelea trichostachya and Pimelea simplex. The Pimelea toxin, simplexin, causes often fatal restriction of the pulmonary venules, with resultant heart impacts and characteristic fluid accumulation (oedema) of the jaw and brisket regions. In certain years heavy livestock losses can occur. Currently, there is no effective vaccine or antidote for Pimelea poisoning and the only management strategy is to reduce contact between toxic plants and susceptible stock, for beef producers to avoid potentially devastating poisoning events. Nevertheless, previous research has demonstrated that prolonged low dose feeding diminished the effect in animals. It was postulated that the animal exposed to prolonged low doses developed a mechanism for detoxifying simplexin, possibly through adaptation of the rumen microbial environment. The present study seeks to investigate the use of a biopolymer/toxin composite to foster toxin-degrading microbe populations. The objectives are to manufacture biopolymer composites based on biodegradable polylactic acid (PLA), polyhydroxyalkanoates (PHAs) and/or polycaprolactone (PCL), as toxin slow-release systems for the rumen that would have broad utility across a range of plant toxins and other beneficial rumen compounds. The poster covers the manufacturing, characterisation and performance of the biopolymers in a simulated rumen environment. Preliminary results of different biopolymers/composites containing Pimelea material and toxin extracts in an in vitro simulated rumen environment for up to 30 days are presented. It was found that the release rate could be tailored by choosing the right type of biopolymer.

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Jamiluddin, J., J. P. Siregar, C. Tezara, M. H. M. Hamdan, and S. M. Sapuan. "Characterisation of cassava biopolymers and the determination of their optimum processing temperatures." Plastics, Rubber and Composites 47, no. 10 (October 20, 2018): 447–57. http://dx.doi.org/10.1080/14658011.2018.1534390.

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Ang, Teik-Hun, Kunlanan Kiatkittipong, Worapon Kiatkittipong, Siong-Chin Chua, Jun Wei Lim, Pau-Loke Show, Mohammed J. K. Bashir, and Yeek-Chia Ho. "Insight on Extraction and Characterisation of Biopolymers as the Green Coagulants for Microalgae Harvesting." Water 12, no. 5 (May 14, 2020): 1388. http://dx.doi.org/10.3390/w12051388.

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This review presents the extractions, characterisations, applications and economic analyses of natural coagulant in separating pollutants and microalgae from water medium, known as microalgae harvesting. The promising future of microalgae as a next-generation energy source is reviewed and the significant drawbacks of conventional microalgae harvesting using alum are evaluated. The performances of natural coagulant in microalgae harvesting are studied and proven to exceed the alum. In addition, the details of each processing stage in the extraction of natural coagulant (plant, microbial and animal) are comprehensively discussed with justifications. This information could contribute to future exploration of novel natural coagulants by providing description of optimised extraction steps for a number of natural coagulants. Besides, the characterisations of natural coagulants have garnered a great deal of attention, and the strategies to enhance the flocculating activity based on their characteristics are discussed. Several important characterisations have been tabulated in this review such as physical aspects, including surface morphology and surface charges; chemical aspects, including molecular weight, functional group and elemental properties; and thermal stability parameters including thermogravimetry analysis and differential scanning calorimetry. Furthermore, various applications of natural coagulant in the industries other than microalgae harvesting are revealed. The cost analysis of natural coagulant application in mass harvesting of microalgae is allowed to evaluate its feasibility towards commercialisation in the industrial. Last, the potentially new natural coagulants, which are yet to be exploited and applied, are listed as the additional information for future study.

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Gallego, Marta, Milagros Arnal, Pau Talens, Fidel Toldrá, and Leticia Mora. "Effect of Gelatin Coating Enriched with Antioxidant Tomato By-Products on the Quality of Pork Meat." Polymers 12, no. 5 (May 2, 2020): 1032. http://dx.doi.org/10.3390/polym12051032.

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The use of edible biopolymers and natural additives obtained from food processing by-products is a sustainable strategy for food packaging applications. Gelatin is a biopolymer with great potential as a coating due to its low cost, high availability, and technological and functional properties. Among them, gelatin can be used as a carrier of bioactive compounds such as antioxidants, which can retard oxidation processes and thus extend the shelf-life of highly-perishable products. This study evaluated the effect of gelatin coating enriched with antioxidant tomato by-products hydrolysate (TBPH) on the quality of pork meat during cold storage. Results showed that TBPH obtained from Alcalase hydrolysis presented antioxidant activity with good stability against cooking. Additionally, chromatographic and mass spectrometry techniques, as well as in silico analysis, were used for the peptidomic characterisation of TBPH. The application of enriched gelatin coating on meat led to some physicochemical changes including increased weight loss and colour differences; however, the pH and water activity, which control meat spoilage, were maintained during storage. Moreover, coating prevented lipid oxidation of meat, and enriched-coated meat presented high antioxidant activity after cooking. These results suggest the positive role of gelatin coating enriched with TBPH in extending the shelf-life of meat during storage.

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Wongkaew, Malaiporn, Pikulthong Chaimongkol, Noppol Leksawasdi, Kittisak Jantanasakulwong, Pornchai Rachtanapun, Phisit Seesuriyachan, Yuthana Phimolsiripol, et al. "Mango Peel Pectin: Recovery, Functionality and Sustainable Uses." Polymers 13, no. 22 (November 11, 2021): 3898. http://dx.doi.org/10.3390/polym13223898.

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Concerns regarding the overconsumption of natural resources has provoked the recovery of biopolymers from food processing biomass. Furthermore, the current market opportunity for pectin in other areas has increased, necessitating the search for alternative pectin resources. This is also a step towards the sustainable and circular green economy. Mango peel is the byproduct of agro-processing and has been used for high value-added components such as polysaccharide biopolymers. Pectin derived from the peel is yet to be exploited to its greatest extent, particularly in terms of its separation and physiochemical properties, which limit its applicability to dietary fiber in culinary applications. The functionality of the mango peel pectin (MPP) strongly depends on the molecular size and degree of esterification which highlight the importance of isolation and characterisation of pectin from this novel resource. This article therefore provides a useful overview of mango peel as a potential biomaterial for the recovery of MPP. Different extraction techniques and the integrated recovery were also discussed. The utilisation of MPP in different industrial schemes are also detailed out from different perspectives such as the pharmaceutical and biotechnology industries. This review convincingly expresses the significance of MPP, providing a sustainable opportunity for food and pharmaceutical development.

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Kus, B., Jaya Kandasamy, S. Vigneswaran, and H. K. Shon. "Water quality characterisation of rainwater in tanks at different times and locations." Water Science and Technology 61, no. 2 (January 1, 2010): 429–39. http://dx.doi.org/10.2166/wst.2010.824.

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Rainwater collected from ten domestic roofs in Sydney and from one in Wollongong, a town south of Sydney, Australia was analysed to determine the water quality and to compare against the Australian Drinking Water Guidelines (ADWG) to determine its suitability as a potable water supply. The pollutants analysed were 13 heavy metals, 8 salts & minerals, pH, ammonia, orthophosphate, conductivity, water hardness, turbidity, total suspended solids, Total dissolved salts & Bicarbonate. The results indicate that the rainwater tested complied to most of the parameters specified in the ADWG. Molecular weight distribution of organic matter from one of the domestic rainwater tanks was analysed in terms of the effects of aging and roof contact. Molecular weight distribution of organic matter in rainwater showed prominent peaks at 37,500 daltons may be due to biopolymers, 850 Da to humic substances, 500 Da to building blocks, 220 Da to low MW acids, and less than 220 Da to amphiphilics. The findings also indicate that the first flush volumes that by-passed the tank can have a significant influence on the water quality in the rainwater tank.

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Sabina, L., B. Kus, H. K. Shon, and J. Kandasamy. "Membrane fouling propensity after adsorption as pretreatment in rainwater: a detailed organic characterisation." Water Science and Technology 58, no. 8 (October 1, 2008): 1535–39. http://dx.doi.org/10.2166/wst.2008.522.

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Organic characterisation in rainwater was investigated in terms of dissolved organic carbon (DOC) and molecular weight distribution (MWD) after powdered activated carbon (PAC) adsorption. PAC adsorption was used as pretreatment to membrane filtration to reduce membrane fouling. The MW of organic matter in rainwater used in this study was in the range of 43,000 Da to 30 Da. Each peak of organic matter consisted of biopolymers (polysaccharides and proteins), humic and fulvic acids, building blocks, low MW acids (hydrolysates of humic substances), low MW neutrals and amphiphilics. Rainwater contained the majority of hydrophilic compounds up to 72%. PAC adsorption removed 33% of total DOC. The removal efficiencies of the hydrophobic and hydrophilic fractions after PAC adsorption were 50% and 27%, respectively. PAC adsorption was found to preferentially remove the hydrophobic fraction. The majority of the smaller MW of 1,100 Da, 820 Da, 550 Da, 90 Da and 30 Da was removed after PAC adsorption. The MFI values decreased from 1,436 s/L2 to 147 s/L2 after PAC adsorption. It was concluded that PAC adsorption can be used as a pretreatment to membrane filtration with rainwater.

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Herranz, Beatriz, Wenceslao Canet, María José Jiménez, Raúl Fuentes, and María Dolores Alvarez. "Characterisation of chickpea flour-based gluten-free batters and muffins with added biopolymers: rheological, physical and sensory properties." International Journal of Food Science & Technology 51, no. 5 (March 6, 2016): 1087–98. http://dx.doi.org/10.1111/ijfs.13092.

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Morris, Kyle, and Louise Serpell. "From natural to designer self-assembling biopolymers, the structural characterisation of fibrous proteins & peptides using fibre diffraction." Chemical Society Reviews 39, no. 9 (2010): 3445. http://dx.doi.org/10.1039/b919453n.

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Kuschert, Sarah, Martin Stroet, Yanni Ka-Yan Chin, Anne Claire Conibear, Xinying Jia, Thomas Lee, Christian Reinhard Otto Bartling, et al. "Facilitating the structural characterisation of non-canonical amino acids in biomolecular NMR." Magnetic Resonance 4, no. 1 (February 24, 2023): 57–72. http://dx.doi.org/10.5194/mr-4-57-2023.

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Abstract. Peptides and proteins containing non-canonical amino acids (ncAAs) are a large and important class of biopolymers. They include non-ribosomally synthesised peptides, post-translationally modified proteins, expressed or synthesised proteins containing unnatural amino acids, and peptides and proteins that are chemically modified. Here, we describe a general procedure for generating atomic descriptions required to incorporate ncAAs within popular NMR structure determination software such as CYANA, CNS, Xplor-NIH and ARIA. This procedure is made publicly available via the existing Automated Topology Builder (ATB) server (https://atb.uq.edu.au, last access: 17 February 2023) with all submitted ncAAs stored in a dedicated database. The described procedure also includes a general method for linking of side chains of amino acids from CYANA templates. To ensure compatibility with other systems, atom names comply with IUPAC guidelines. In addition to describing the workflow, 3D models of complex natural products generated by CYANA are presented, including vancomycin. In order to demonstrate the manner in which the templates for ncAAs generated by the ATB can be used in practice, we use a combination of CYANA and CNS to solve the structure of a synthetic peptide designed to disrupt Alzheimer-related protein–protein interactions. Automating the generation of structural templates for ncAAs will extend the utility of NMR spectroscopy to studies of more complex biomolecules, with applications in the rapidly growing fields of synthetic biology and chemical biology. The procedures we outline can also be used to standardise the creation of structural templates for any amino acid and thus have the potential to impact structural biology more generally.

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Koenig, S., M. Bremer, J. Appelt, A. C. Bansleben, H. Unbehaun, and G. Kerns. "Characterisation of volatile organic compounds (VOC) in different lignin and their reduction by enzymatic modification for the production of fibre-reinforced biopolymers." Journal of Biotechnology 150 (November 2010): 380–81. http://dx.doi.org/10.1016/j.jbiotec.2010.09.471.

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Madhanasundareswari, K., Reshmi Gopalakrishnan, and K. Gayathri. "Production And Fusion Of Antimicrobial Agents With Bio Plastic Using Palmyra Sprout." Journal of University of Shanghai for Science and Technology 24, no. 1 (January 9, 2022): 216–30. http://dx.doi.org/10.51201/jusst/22/0131.

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The problems linked to plastic wastes have led to the development of biodegradable plastics. More specifically, biodegradable bioplastics are the polymers that are mineralized into carbon dioxide, methane, water, inorganic compounds, or biomass through the enzymatic action of specific microorganisms. They could, therefore, be a suitable and environmentally friendly substitute to conventional petrochemical plastics. The physico-chemical structure of the biopolymers, the environmental conditions, as well as the microbial populations to which the bioplastics are exposed to are the most influential factors to biodegradation. The Borassus flabellifer is a tall and erect palm, with large, fan-shaped leaves which are quite unlike the pinnate leaves of other palms. Borassus is from a Greek word describing the leathery covering of the fruit and flabellifer means “fan bearer”. In recent years, India stands first in the world in terms of its wealth of Palmyra (Borassus flabellifer population nearly 122 million palms. In this study overall purpose was to investigate the utilization of food industry wastes in order for the bioplastic production. To achieve this objective the production of bioplastic from palmyra sprout investigated. In addition, some properties of produced bioplastic such as water, absorption capacity, solubility and biodegradability, characterisation studies were analysed. Journal of University of Shanghai for Science and Technology ISSN: 1007-6735 Volume

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Perez-Moral, Natalia, Jean-Michel Plankeele, Claire Domoney, and Frederick J. Warren. "Ultra-high performance liquid chromatography-size exclusion chromatography (UPLC-SEC) as an efficient tool for the rapid and highly informative characterisation of biopolymers." Carbohydrate Polymers 196 (September 2018): 422–26. http://dx.doi.org/10.1016/j.carbpol.2018.05.049.

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Concha Fuentealba, Jose L., Luis Arteaga-Pérez, Irene Gonzalez-Torre, and Jose Norambuena-Contreras. "Synthesis and characterisation of biocapsules containing low-cost rejuvenators for asphalt self-healing." RILEM Technical Letters 6 (March 15, 2021): 1–7. http://dx.doi.org/10.21809/rilemtechlett.2021.129.

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This study aimed to characterise polynuclear biocapsules containing low-cost rejuvenating agents for asphalt self-healing. Capsules consisted of a biopolymeric matrix of calcium alginate containing cooking oil and mineral oil as rejuvenating agents, being synthesised using ionic gelation through the pumping dripping technique. The physical-chemical properties of the oil-in-biopolymer emulsions and their stability over time were studied. The morphological and thermophysical properties of the biocapsules, as well as the encapsulation efficiency of the rejuvenating agents, were quantified and characterised by microscopic techniques and laboratory tests. Main results showed that emulsions should be used for encapsulation purposes within a period no longer than 3h, reducing the effect of instability phenomena. Besides, the biopolymer-based polynuclear capsules presented uniform size, internal multicavity microstructure resulting in high encapsulation efficiencies and thermal stability at high temperatures, proving that cooking oil and mineral oil can be potentially used as low-cost rejuvenating agents and thermally stable additives for asphalt self-healing purposes.

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Ekere, Itohowo, Brian Johnston, Fideline Tchuenbou-Magaia, David Townrow, Szymon Wojciechowski, Adam Marek, Jan Zawadiak, et al. "Bioconversion Process of Polyethylene from Waste Tetra Pak® Packaging to Polyhydroxyalkanoates." Polymers 14, no. 14 (July 12, 2022): 2840. http://dx.doi.org/10.3390/polym14142840.

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Presented herein are the results of a novel recycling method for waste Tetra Pak® packaging materials. The polyethylene (PE-T) component of this packaging material, obtained via a separation process using a “solvents method”, was used as a carbon source for the biosynthesis of polyhydroxyalkanoates (PHAs) by the bacterial strain Cupriavidus necator H16. Bacteria were grown for 48–72 h, at 30 °C, in TSB (nitrogen-rich) or BSM (nitrogen-limited) media supplemented with PE-T. Growth was monitored by viable counting. It was demonstrated that C. necator utilised PE-T in both growth media, but was only able to accumulate 40% w/w PHA in TSB supplemented with PE-T. Only 1.5% w/w PHA was accumulated in the TSB control, and no PHA was detected in the BSM control. Extracted biopolymers were characterised by nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR) spectroscopy, electrospray tandem mass spectrometry (ESI-MS/MS), gel permeation chromatography (GPC), and accelerator mass spectrometry (AMS). The characterisation of PHA by ESI-MS/MS revealed that PHA produced by C. necator in TSB supplemented with PE-T contained 3-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate co-monomeric units. AMS analysis also confirmed the presence of 96.73% modern carbon and 3.27% old carbon in PHA derived from Tetra Pak®. Thus, this study demonstrates the feasibility of our proposed recycling method for waste Tetra Pak® packaging materials, alongside its potential for producing value-added PHA, and the ability of 14C analysis in validating this bioconversion process.

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Ludwig, Roland, Florian Csarman, Lena Wohlschlager, and Stefan Scheiblbrandner. "High-resolution study of fungal enzymes." Impact 2019, no. 9 (December 20, 2019): 15–17. http://dx.doi.org/10.21820/23987073.2019.9.15.

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Current processes for lignocellulose deconstruction are unspecific and produce some constituents in poor quality. Specific biocatalysts could achieve optimal segregation together with minimal damage to cellulose and lignin and provide high-quality feedstocks for industry. Naturally occurring fungal oxidoreductases perform this task, but their characterisation - and hence their optimisation for industrial application - is difficult because of the experimental challenges. The mission of OXIDISE to develop appropriate methods to characterise lignocellulose degrading oxidoreductases, i.e. elucidate their conversions rates and to resolve their distribution and interaction in vicinity of their polymeric substrates. High-resolution techniques will be adapted to specifically detect fungal oxidoreductases like lytic polysaccharide monooxygenase, cellobiose dehydrogenase, laccase, lignin peroxidase, or members of the GMC oxidoreductase superfamily. These enzymes are all involved in the oxidative attack of recalcitrant biopolymers and are present in over 90% of fungal genomes. To overcome problems of current assaying techniques such as their low spatial and temporal resolution, OXIDISE will develop and apply techniques based on microelectrodes, scanning electron microscopy, surface plasmon resonance and fluorescence microscopy thereby pursuing three objectives: 1) study the interaction of all major oxidoreductases secreted by fungi in regard to electron transfer, regeneration of redox species and substrate cascading; 2) resolve the distribution of secreted oxidoreductases on cellulosic and lignocellulosic substrates at high resolution; 3) transfer the developed techniques to natural lignocellulose samples with growing fungal hyphae and study the secreted oxidoreductase activities. OXIDISE strives to establish new techniques to elucidate the kinetics and interactions of oxidoreductases - a long neglected enzyme class for lignocellulose depolymerisation.

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Suput, Danijela, Vera Lazic, Senka Popovic, Nevena Hromis, and Sandra Bulut. "Biopolymer films synthesis and characterisation." Journal on Processing and Energy in Agriculture 21, no. 2 (2017): 9–12. http://dx.doi.org/10.5937/jpea1701009s.

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Norambuena-Contreras, Jose, Jose Concha, Luis Arteaga-Pérez, and Irene Gonzalez-Torre. "Synthesis and Characterisation of Alginate-Based Capsules Containing Waste Cooking Oil for Asphalt Self-Healing." Applied Sciences 12, no. 5 (March 7, 2022): 2739. http://dx.doi.org/10.3390/app12052739.

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This paper presents the synthesis and characterisation of biopolymeric capsules for asphalt self-healing. A sodium alginate biopolymer extracted from the cell wall of brown algae was used as the encapsulating material to contain Waste Cooking Oil (WCO) as a potential encapsulated rejuvenating agent for aged bitumen. Polynuclear capsules were synthesised by ionic gelation. The size, surface aspect and internal structure of the WCO capsules were evaluated using Optical and Scanning Electron Microscopy. The physical-chemical properties and thermal stability of the WCO capsules and their components were also evaluated. Moreover, the diffusion process and self-healing capability of the released WCO on cracked bitumen test samples were determined by image analysis through fluorescence microscopy. The main results of this study showed that the WCO capsules presented a suitable morphology to be mixed in asphalt mixtures. WCO capsules and their components presented mechanical and thermal stability and physical-chemical properties which suggest their feasibility for self-healing applications. It was proven that the encapsulated WCO can diffuse in the aged bitumen, reducing its viscosity and promoting the self-healing of microcracks.

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Bulut, Sandra, Vera Lazic, Senka Popovic, Nevena Hromis, and Danijela Suput. "Mono- and bilayer biopolymer films: Synthesis and characterisation." Journal on Processing and Energy in Agriculture 21, no. 4 (2017): 214–18. http://dx.doi.org/10.5937/jpea1704214b.

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Kaurin, Tea, Tanja Pušić, and Mirjana Čurlin. "Biopolymer Textile Structure of Chitosan with Polyester." Polymers 14, no. 15 (July 29, 2022): 3088. http://dx.doi.org/10.3390/polym14153088.

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The research deals with functionalization of a standard polyester fabric with biopolymer chitosan, whose premises are multifunctional and favour ecological effects. Due to the incompatibility of synthetic and natural polymers, the chitosan treatment was preceded by alkaline hydrolysis with sodium hydroxide with the addition of cationic and anionic surfactants as promoters. Compatibility of the chitosan with untreated and alkali-hydrolyzed fabrics was performed by analysis of mechanical and physico-chemical properties. The number of characterisation procedures performed required the use of hierarchical cluster analysis (HCA) to identify homogeneous groups or clusters in which similarities and differences between samples are visible. Almost all applied methods and evaluation parameters have shown that alkaline hydrolysis of polyester fabric has the best potential for functionalization with chitosan. Therefore, the addition of surfactants as promoters during alkaline hydrolysis is not necessary in the pretreatment process phase.

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Lombardi, J. P., R. S. Aga, E. M. Heckman, and C. M. Bartsch. "Characterisation of DNA biopolymer‐based UV photodetector fabricated by inkjet printing." Electronics Letters 51, no. 10 (May 2015): 778–80. http://dx.doi.org/10.1049/el.2015.0577.

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SUN, F., X. WANG, and X. LI. "Visualisation and characterisation of biopolymer clusters in a submerged membrane bioreactor." Journal of Membrane Science 325, no. 2 (December 1, 2008): 691–97. http://dx.doi.org/10.1016/j.memsci.2008.08.048.

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Dang Thi Thanh, Nhan, Don Truong Thi, Thang Le Quoc, Tien Tran Dong, and Son Le Lam. "Fabrication and characterisation of Fe2O3/chitosan aerogel-like spheres." Vietnam Journal of Catalysis and Adsorption 10, no. 1 (November 25, 2021): 74–78. http://dx.doi.org/10.51316/jca.2021.012.

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Presently, biopolymer materials have been given more attention for their outstanding properties, high efficiencies and promising applications in various fields. In this study, Fe2O3/chitosan aerogel-like spheres were successfully prepared from chitosan and FeCl3 by sol–gel process and freeze-drying to provide high-surface area materials. The factors affecting the material synthesis have been studied. The asprepared Fe2O3/chitosan material was characterized by Infrared Spectroscopy (IR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) methods. The results showed that the aerogel spheres have a hollow structure made of chitosan nanofibril networks. Fe2O3 nanoparticles get high crystallinity and have an average particle size of 33 nm.

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Owusu, M., and H. Osei. "Biopolymer Drill-in Fluid Performance for Different Rheological Models using Statistical Characterisation." Ghana Mining Journal 19, no. 1 (June 30, 2019): 86–92. http://dx.doi.org/10.4314/gm.v19i1.10.

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Appropriate selection of rheological models is important for hydraulic calculations of pressure loss prediction and hole cleaning efficiency of drilling fluids. Power law, Bingham-Plastic and Herschel-Bulkley models are the conventional fluid models used in the oilfield. However, there are other models that have been proposed in literature which are under/or not utilized in the petroleum industry. The primary objective of this paper is to recommend a rheological model that best-fits the rheological behaviour of xanthan gum-based biopolymer drill-in fluids for hydraulic evaluations. Ten rheological models were evaluated in this study. These rheological models have been posed deterministically and due to the unrealistic nature have been replaced by statistical models, by adding an error (disturbance) term and making suitable assumptions about them. Rheological model parameters were estimated by least-square regression method. Models like Sisko and modified Sisko which are not conventional models in oil industry gave a good fit. Modified Sisko model which is a four parameter rheological model was selected as the best-fit model since it produced the least residual mean square of 0.61 Ibf2/100ft4. There is 95% certainty that the true best-fit curve lies within the confidence band of this function of interest. Keywords: Biopolymer; Least-Square Regression; Residual Mean Squares; Rheologram

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Manimohan, Murugaiyan, Sivashanmugam Pugalmani, K. Ravichandran, and Mohamed Aboobucker Sithique. "Synthesis and characterisation of novel Cu(ii)-anchored biopolymer complexes as reusable materials for the photocatalytic degradation of methylene blue." RSC Advances 10, no. 31 (2020): 18259–79. http://dx.doi.org/10.1039/d0ra01724h.

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Kuo, Shyh Ming, Benjamin Teong, Ioannis Manousakas, and Chun-Hsu Yao. "Preparation and characterisation of biopolymeric volvox-like spheres: a feasibility study." Micro & Nano Letters 7, no. 10 (October 1, 2012): 1011–14. http://dx.doi.org/10.1049/mnl.2012.0397.

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Srinivasan, R., V. Geetha, J. Seetharaman, and S. Mohan. "A Unique Or Essentially Unique Single Parametric Characterisation Of Biopolymeric Structures." Journal of Biomolecular Structure and Dynamics 11, no. 3 (December 1993): 583–96. http://dx.doi.org/10.1080/07391102.1993.10508017.

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Kaczmarczyk, Kacper, Joanna Kruk, Paweł Ptaszek, and Anna Ptaszek. "Plantago Ovata Husk: An Investigation of Raw Aqueous Extracts. Osmotic, Hydrodynamic and Complex Rheological Characterisation." Molecules 28, no. 4 (February 9, 2023): 1660. http://dx.doi.org/10.3390/molecules28041660.

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The aim of the study was to characterize raw aqueous extracts from Plantago ovata husk in terms of molecular chain mass, osmotic, hydrodynamic, and rheological properties. The raw extracts used in this study have not been yet investigated in the indicated research area. Determination of the molecular weight of the chains present in the extract was performed by gel permeation chromatography (GPC). Osmotic properties were characterized using membrane osmometry. Rheological properties were investigated via classical rotational rheology with normal force measurements, as well as less common but equally important measurements of extensional viscosity. Two types of chains with an average molecular mass of 200 and 1780 kDa were found. The values of the first virial coefficient (B2) indicate the predominance of biopolymer-biopolymer interactions. The hydrodynamic radius established at 25 and 30 °C was 74 and 67 nm, respectively, and lower than at 40 °C (>600 nm). The first critical concentration was determined: c*=0.11 g·dL−1. The dominance of negative normal force values resulting from the formation of a pseudo-gel structure of the heteroxylates was demonstrated. Extensional viscosity measurement results revealed that the studied extracts cannot be treated as simple shear-thinning fluids, as indicated by shear flow, but should be considered as viscoelastic fluids.

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Mahjoub, Hella, Codruța Sarosi, Olga Orasan, and Aniela Saplonţai-Pop. "SEM Characterisation of a Tricalcium Phosphate – Chitosan - PMMA Cement." Key Engineering Materials 614 (June 2014): 47–51. http://dx.doi.org/10.4028/www.scientific.net/kem.614.47.

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Synthetic Polymers, both organic and inorganic, are used in a wide variety of biomedical applications. The polymers can be biodegradable or nondegradable. Chitosan (CH), which is a naturally biodegradable, non-toxic biopolymer obtained by the deacetylation of chitin, has been demonstrated to have an intrinsic activity against a wide spectrum of bacteria, filamentous fungi and yeast. Several investigators have studied reinforced tricalcium phosphate (TCP), Chitosan, polymethylmethacrylate (PMMA)/methyl methacrylate (MMA) as potential cement. In fact addition of TCP with chitosan to the cement can improve biocompatibility and also enhance the mechanical properties of the cement because of its both biocompatibility and osteoconductivity properties. Crystalline phase and microstructure of the cement with hydroxyapatite - poly (methyl-methacrylate) were characterized by scanning electron microscopy (SEM; FEI Company), with the purpose to draw solid conclusions about the influence of the particles size, form and uniform mixing on the chemical process. We acquired PMMA sorted according to granulometric size.

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Rippel, G., Gy Bacsur, Á. Bede, Á. Sándi, and L. Szepesy. "Characterisation of Wide-Pore Reversed Phase Columns for Biopolymer Separations. II. Multiparametric Evaluation." Journal of Liquid Chromatography & Related Technologies 20, no. 11 (June 1997): 1667–87. http://dx.doi.org/10.1080/10826079708006325.

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Bunt, C. R., S. A. Stelting, D. A. Wright, and J. Swaminathan. "Preformulation characterisation of zeolite core materials in biocontrol products." New Zealand Plant Protection 63 (August 1, 2010): 284. http://dx.doi.org/10.30843/nzpp.2010.63.6602.

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Bioshield is a unique biocontrol agent that is used for control of the New Zealand grass grub (Costelytra zealandica) It consists of a core of zeolite with a biopolymer coating containing the bacterium Serratia entomophila Assessments of various zeolites (Z1BC Z1BDW Z1CG and Z1BI from New Zealand (NZZs) and AUFM 4/1 and AUZB from Australia (AZs)) were carried out prior to formulation Physical characteristics such as friability and water absorption and sorption were measured and success of bacterial coating was assessed by light microscopy and differential staining scanning electron microscopy (SEM) and cell loading (cfu/g) Friability assessment of NZZs found approximately 5 mass loss while AZs did not lose any mass NZZs absorbed approximately 30 w / w while AZs 10 w / w water Water sorption to zeolites appeared to monolayer in nature although NZZs and AZs monolayer adsorption isotherms appear to differ being type II and type I respectively SEM analysis showed the surface of NZZs to be porous and populated by colloidal particles while AZs appeared very smooth and lacking in surface features Success of coating S entomophila onto NZZs and AZs was confirmed by SEM enumeration and livedead staining

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Miranda‐Villagómez, Erika, Miguel Ángel Aguilar‐Méndez, Fernando Carlos Gómez‐Merino, Elba Ronquillo de Jesús, Manuel Sandoval‐Villa, Prometeo Sánchez‐García, and Libia Iris Trejo‐Téllez. "Synthesis of biopolymeric particles loaded with phosphorus and potassium: characterisation and release tests." IET Nanobiotechnology 13, no. 5 (April 29, 2019): 493–97. http://dx.doi.org/10.1049/iet-nbt.2018.5035.

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El-Sayed, S., and Adel M. El Sayed. "Synthesis, characterisation, dielectric, and optical properties of the chitosan/poly(ethylene glycol)/magnesia biopolymer nanocomposites." Materials Technology 34, no. 10 (April 16, 2019): 602–14. http://dx.doi.org/10.1080/10667857.2019.1603810.

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Moussout, Hamou, Hammou Ahlafi, Mustapha Aazza, Omar Zegaoui, and Charaf El Akili. "Adsorption studies of Cu(II) onto biopolymer chitosan and its nanocomposite 5%bentonite/chitosan." Water Science and Technology 73, no. 9 (February 8, 2016): 2199–210. http://dx.doi.org/10.2166/wst.2016.075.

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Chitosan (CS) and nanocomposite 5%bentonite/chitosan (5%Bt/CS) prepared from the natural biopolymer CS were tested to remove Cu(II) ions using a batch adsorption experiment at various temperatures (25, 35 and 45°C). X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis (TGA/DTA) were used in CS and the nanocomposite characterisation. This confirmed the exfoliation of bentonite (Bt) to form the nanocomposite. The adsorption kinetics of copper on both solids was found to follow a pseudo-second-order law at each studied temperature. The Cu(II) adsorption capacity increased as the temperature increased from 25 to 45°C for nanocomposite adsorbent but slightly increased for CS. The data were confronted to the nonlinear Langmuir, Freundlich and Redlich–Peterson models. It was found that the experimental data fitted very well the Langmuir isotherm over the whole temperature and concentration ranges. The maximum monolayer adsorption capacity for the Cu(II) was 404–422 mg/g for CS and 282–337 mg/g for 5%Bt/CS at 25–45°C. The thermodynamic study showed that the adsorption process was spontaneous and endothermic. The complexation of Cu(II) with NH2 and C = O groups as active sites was found to be the main mechanism in the adsorption processes.

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Pavaloiu, Ramona-Daniela, Fawzia Sha At, Mihaela Eremia, Cristina Hlevca, Maria Petrescu, Mousa Sha�at, and Claudia Sevcenco. "Formulation and Characterisation of Pullulan Acetate Nanoparticles Loaded with 5-Fluorouracil." Materiale Plastice 59, no. 2 (July 1, 2022): 138–44. http://dx.doi.org/10.37358/mp.22.2.5593.

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This study was geared to analyze the preparation methods of pullulan acetate-based nanoparticles loaded with 5-fluorouracil, as well as the potential of pullulan as a biopolymer matrix for obtaining nanoparticles applied in the delivery of anticancer drugs (5-FU). Various methods were used to produce pullulan acetate-based nanoparticles loaded with 5-FU, including nanoprecipitation, modified nanoprecipitation, and double emulsion. Pullulan was previously chemically modified with acetic anhydride, dimethylformamide and pyridine, and yielded pullulan acetate. Pullulan was made using the Aureobasidium pullulans strain through a fermentation procedure. UV-Vis Spectro-photometric and dynamic light scattering (DLS) methods were used to assess entrapment effectiveness, size, and polydispersity index (PDI) of pullulan acetate-based nanoparticles loaded with 5-FU. Based on the properties of the nanoparticles obtained, the optimum preparation method was chosen. The maximum entrapment efficiency was found in pullulan acetate nanoparticles loaded with 5-FU generated by a double emulsion method. The mean hydrodynamic size and PDI of all nanoparticles were adequate. The best formulation showed faster 5-FU release profile in acid phosphate-buffered saline (pH 5) than in phosphate-buffered saline pH 7.4. According to the findings, pullulan derivatives have a great potential for producing nanoparticles that might be used to deliver anticancer medicines.

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Milinkovic-Budincic, Jelena, Lidija Petrovic, Jadranka Fraj, Sandra Bucko, Jaroslav Katona, and Ljiljana Spasojevic. "Rheological characterisation of chitosan/sodium lauryl ether sulfate complexes." Acta Periodica Technologica, no. 50 (2019): 152–62. http://dx.doi.org/10.2298/apt1950152m.

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Chitosan is a cationic biopolymer, which attracts more and more attention in recent years, due to its exceptional physical and chemical properties, expressive biocompatibility and possibilities of obtaining from renewable sources. Formed polymer/surfactant complexes affect changes in the rheological properties and the final result is the formation of coacervates. The purpose of this study was to investigate the rheological properties of aqueous solutions of cationic polyelectrolyte, chitosan and sodium lauryl ether sulfate (SLES), an anionic surfactant, widely used in the cosmetics industry. Using the Thermo Haake RS600 rheometer, changes in the rheological and elastic properties of chitosan and SLES mixtures have been identified, gained as a result of the interaction of the components. In all examined samples coefficient of thixotropy was increasing with increase SLES concentration and achieves a maximum value at the mass ratio chitosan:SLES 1:2, after which it reduces. The oscillatory measurements in mixtures, performed by amplitude sweep method at low oscillating frequency 1 Hz, show that the linear viscoelastic region increases with increasing SLES concentration up to the same chitosan:SLES mass ratio. By monitoring the changes in the rheological parameters of the mixtures over five days, it was observed that the viscosity, the coefficient of thixotropy and elasticity were increasing, indicating that changes in the system occur over a longer period of time. In that manner, obtained results indicate the possibility of using rheological methods for a more detailed description of the interaction in the chitosan/SLES mixtures, important for their application in cosmetics and pharmaceutical industries.

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Manimohan, Murugaiyan, Sivashanmugam Pugalmani, and Mohamed Aboobucker Sithique. "Biologically Active Water Soluble Novel Biopolymer/Hydrazide Based O-Carboxymethyl Chitosan Schiff Bases: Synthesis and Characterisation." Journal of Inorganic and Organometallic Polymers and Materials 30, no. 9 (March 13, 2020): 3658–76. http://dx.doi.org/10.1007/s10904-020-01487-9.

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40

Islam, Saniyat, Lyndon Arnold, and Rajiv Padhye. "Comparison and Characterisation of Regenerated Chitosan from 1-Butyl-3-methylimidazolium Chloride and Chitosan from Crab Shells." BioMed Research International 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/874316.

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Chitosan is a biopolymer derived from chitin which is naturally occurring in the exoskeleton of crustaceans. This paper reports dissolution and regeneration of chitosan by directly dissolving in an ionic liquid solvent, 1-butyl-3-methylimidazolium chloride (BMIMCl). This will provide an ideal platform to solubilise these kinds of polymers to achieve the dissolution. The current study dissolved chitosan from crab shell utilising BMIMCl as a solvent and characterised the resultant regenerated polymer. The regenerated chitosan showed increased hydrogen bonding when characterised by Fourier transform infrared (FTIR) spectral analysis. In addition, the study also compared the characteristics of regenerated and generic chitosan. The regenerated chitosan was also evaluated for antimicrobial properties and showed to possess antibacterial features similar to the commercial grade. This method can be utilised in future for blending of polymers with chitosan in a dissolved phase.

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Watts, Samuel, Bettina Tran, and Stefan Salentinig. "(Anti)viral Material Design Guided by Scattering Methods." CHIMIA 76, no. 10 (October 26, 2022): 846. http://dx.doi.org/10.2533/chimia.2022.846.

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Viruses are nature’s own nanoparticles that are highly symmetric and monodisperse in size and shape with well-defined surface chemistry. They have evolved for optimal cell interactions, genetic information delivery and replication by the host cell over millions of years. These features render them into very efficient pathogens that place a severe burden onto the health of our society. At the same time, they are highly interesting objects for colloidal studies and building blocks for advanced bio-inspired materials for health applications. Their characterisation requires sophisticated experimental techniques such as scattering of X-rays, neutrons, and light to probe structures and interactions from the nanometre to the micrometre length-scale in solution. This contribution summarizes the recent progress in the field of virus self-assembly and virus-based biopolymer composites for advanced material design. It discusses the advances and highlights some of the challenges in the characterization of structure and dynamics in these materials with a focus on scattering techniques. It further demonstrates selected applications in the field of food and water purification.

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Godugu, Deepika, and Sashidhar Rao Beedu. "Synthesis, characterisation and anti‐tumour activity of biopolymer based platinum nanoparticles and 5‐fluorouracil loaded platinum nanoparticles." IET Nanobiotechnology 13, no. 3 (December 20, 2018): 282–92. http://dx.doi.org/10.1049/iet-nbt.2018.5171.

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43

Katukam, Vani, Karuna Rupula, and Sashidhar Rao Beedu. "Synthesis and characterisation of novel biopolymer stabilised organic Pt-nanocomposite: assessment of its antioxidant and antitumour properties." IET Nanobiotechnology 14, no. 9 (December 1, 2020): 889–98. http://dx.doi.org/10.1049/iet-nbt.2020.0069.

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Morgan-Sagastume, F., F. Valentino, M. Hjort, D. Cirne, L. Karabegovic, F. Gerardin, P. Johansson, et al. "Polyhydroxyalkanoate (PHA) production from sludge and municipal wastewater treatment." Water Science and Technology 69, no. 1 (October 16, 2013): 177–84. http://dx.doi.org/10.2166/wst.2013.643.

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Polyhydroxyalkanoates (PHAs) are biodegradable polyesters with comparable properties to some petroleum-based polyolefins. PHA production can be achieved in open, mixed microbial cultures and thereby coupled to wastewater and solid residual treatment. In this context, waste organic matter is utilised as a carbon source in activated sludge biological treatment for biopolymer synthesis. Within the EU project Routes, the feasibility of PHA production has been evaluated in processes for sludge treatment and volatile fatty acid (VFA) production and municipal wastewater treatment. This PHA production process is being investigated in four units: (i) wastewater treatment with enrichment and production of a functional biomass sustaining PHA storage capacity, (ii) acidogenic fermentation of sludge for VFA production, (iii) PHA accumulation from VFA-rich streams, and (iv) PHA recovery and characterisation. Laboratory- and pilot-scale studies demonstrated the feasibility of municipal wastewater and solid waste treatment alongside production of PHA-rich biomass. The PHA storage capacity of biomass selected under feast–famine with municipal wastewater has been increased up to 34% (g PHA g VSS−1) in batch accumulations with acetate during 20 h. VFAs obtained from waste activated sludge fermentation were found to be a suitable feedstock for PHA production.

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45

Alsaadi, Athraa, Sree Selva Kumar Ganesen, Tan Suet May Amelia, Radwa Moanis, Eveline Peeters, Sevakumaran Vigneswari, and Kesaven Bhubalan. "Polyhydroxyalkanoate (PHA) Biopolymer Synthesis by Marine Bacteria of the Malaysian Coral Triangle Region and Mining for PHA Synthase Genes." Microorganisms 10, no. 10 (October 18, 2022): 2057. http://dx.doi.org/10.3390/microorganisms10102057.

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Polyhydroxyalkanoate (PHA), a biodegradable and plastic-like biopolymer, has been receiving research and industrial attention due to severe plastic pollution, resource depletion, and global waste issues. This has spurred the isolation and characterisation of novel PHA-producing strains through cultivation and non-cultivation approaches, with a particular interest in genes encoding PHA synthesis pathways. Since sea sponges and sediment are marine benthic habitats known to be rich in microbial diversity, sponge tissues (Xestospongia muta and Aaptos aaptos) and sediment samples were collected in this study from Redang and Bidong islands located in the Malaysian Coral Triangle region. PHA synthase (phaC) genes were identified from sediment-associated bacterial strains using a cultivation approach and from sponge-associated bacterial metagenomes using a non-cultivation approach. In addition, phylogenetic diversity profiling was performed for the sponge-associated bacterial community using 16S ribosomal ribonucleic acid (16S rRNA) amplicon sequencing to screen for the potential presence of PHA-producer taxa. A total of three phaC genes from the bacterial metagenome of Aaptos and three phaC genes from sediment isolates (Sphingobacterium mizutaii UMTKB-6, Alcaligenes faecalis UMTKB-7, Acinetobacter calcoaceticus UMTKB-8) were identified. Produced PHA polymers were shown to be composed of 5C to nC monomers, with previously unreported PHA-producing ability of the S. mizutaii strain, as well as a 3-hydroxyvalerate-synthesising ability without precursor addition by the A. calcoaceticus strain.

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Godugu, Deepika, and Sashidhar Rao Beedu. "Biopolymer‐mediated synthesis and characterisation of platinum nanocomposite and its anti‐fungal activity against A. parasiticus and A. flavus." Micro & Nano Letters 13, no. 10 (October 2018): 1491–96. http://dx.doi.org/10.1049/mnl.2018.5097.

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47

Boostani, Sareh, Mahmoud Aminlari, Marzieh Moosavi-nasab, Mehrdad Niakosari, and Gholamreza Mesbahi. "Fabrication and characterisation of soy protein isolate-grafted dextran biopolymer: A novel ingredient in spray-dried soy beverage formulation." International Journal of Biological Macromolecules 102 (September 2017): 297–307. http://dx.doi.org/10.1016/j.ijbiomac.2017.04.019.

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48

Jasiukaitytė-Grojzdek, Edita, Filipa A. Vicente, Miha Grilc, and Blaž Likozar. "Ambient-Pressured Acid-Catalysed Ethylene Glycol Organosolv Process: Liquefaction Structure–Activity Relationships from Model Cellulose–Lignin Mixtures to Lignocellulosic Wood Biomass." Polymers 13, no. 12 (June 17, 2021): 1988. http://dx.doi.org/10.3390/polym13121988.

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Raising the awareness of carbon dioxide emissions, climate global warming and fossil fuel depletion has renewed the transition towards a circular economy approach, starting by addressing active bio-economic precepts that all portion amounts of wood are valorised as products. This is accomplished by minimizing residues formed (preferably no waste materials), maximizing reaction productivity yields, and optimising catalysed chemical by-products. Within framework structure determination, the present work aims at drawing a parallel between the characterisation of cellulose–lignin mixture (derived system model) liquefaction and real conversion process in the acidified ethylene glycol at moderate process conditions, i.e., 150 °C, ambient atmospheric pressure and potential bio-based solvent, for 4 h. Extended-processing liquid phase is characterized considering catalyst-transformed reactant species being produced, mainly recovered lignin-based polymer, by quantitative 31P, 13C and 1H nuclear magnetic resonance (NMR) spectroscopy, as well as the size exclusion- (SEC) or high performance liquid chromatography (HPLC) separation for higher or lower molecular weight compound compositions, respectively. Such mechanistic pathway analytics help to understand the steps in mild organosolv biopolymer fractionation, which is one of the key industrial barriers preventing a more widespread manufacturing of the biomass-derived (hydroxyl, carbonyl or carboxyl) aromatic monomers or oligomers for polycarbonates, polyesters, polyamides, polyurethanes and (epoxy) resins.

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49

Stiufiuc, Rares, Cristian Iacovita, Raul Nicoara, Gabriela Stiufiuc, Adrian Florea, Marcela Achim, and Constantin M. Lucaciu. "One-Step Synthesis of PEGylated Gold Nanoparticles with Tunable Surface Charge." Journal of Nanomaterials 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/146031.

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The present work reports a rapid, simple and efficient one-step synthesis and detailed characterisation of stable aqueous colloids of gold nanoparticles (AuNPs) coated with unmodified poly(ethylene)glycol (PEG) molecules of different molecular weights and surface charges. By mixing and heating aqueous solutions of PEG with variable molecular chain and gold(III) chloride hydrate (HAuCl4) in the presence of NaOH, we have successfully produced uniform colloidal 5 nm PEG coated AuNPs of spherical shape with tunable surface charge and an average diameter of 30 nm within a few minutes. It has been found out that PEGylated AuNPs provide optical enhancement of the characteristic vibrational bands of PEG molecules attached to the gold surface when they are excited with both visible (532 nm) and NIR (785 nm) laser lines. The surface enhanced Raman scattering (SERS) signal does not depend on the length of the PEG molecular chain enveloping the AuNPs, and the stability of the colloid is not affected by the addition of concentrated salt solution (0.1 M NaCl), thus suggesting their potential use forin vitroandin vivoapplications. Moreover, by gradually changing the chain length of the biopolymer, we were able to control nanoparticles’ surface charge from −28 to −2 mV, without any modification of the Raman enhancement properties and of the colloidal stability.

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P. R, Kalpana. "Synthesis, Characterisation and Antimicrobial Potential of Novel N-Alkylated Pyrrole Derivatives of Chitosan." Bioscience Biotechnology Research Communications 14, no. 4 (December 25, 2021): 1730–36. http://dx.doi.org/10.21786/bbrc/14.4.52.

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Chitosan, a cationic biopolymer is a major derivative of chitin. It is biocompatible, non-toxic and environ-friendly material and has broad spectrum antimicrobial activity. However, it is less effective in neutral or basic conditions due to its solubility only in acidic medium. Therefore, chemical modification with suitable groups is necessary to enhance the potency of chitosan. The present study was mainly conducted to explore the effect of structural modifications on antimicrobial potential of chitosan. N-Methyl, N-Ethyl and N-Propyl pyrrole were reacted with N-chloroacyl-6-O-triphenylmethylchitosan prepared by stepwise modification of chitosan to form N-Methyl, N-Ethyl and N-Propyl pyrrole derivatives of chitosan. Structural characterization of these pyrrole derivatives was done by IR, NMR, XRD, DSC and Elemental Analysis. The gram-negative bacterium Escherichia coli, gram-positive bacterium Staphylococcus aureus were selected for antibacterial activity and the fungus C. albicans was selected for antifungal activity by agar diffusion method and MIC method. Antimicrobial activity of the N-Methyl, N-Ethyl and N-Propyl pyrrole derivatives on E. coli, S. aureus and C. albicans showed an inhibitory effect on all the organisms. The potency of inhibition was found to be varied with the substitutions. The maximum activity was shown by N-pyrrolylpropylchitosan against E. coli (zone of inhibition 1.2±0.05cm, MIC 0.15±0.03mg/ml), S. aureus (zone of inhibition 1.4±0.03cm, MIC 0.15±0.01mg/ml), C. albicans (zone of inhibition 0.8±0.03cm, MIC 0.2±0.03mg/ml). The study also confirmed that all the three derivatives exhibited higher inhibition than that of chitosan against E. coli (zone of inhibition 0.7±0.03cm, MIC 0.09±0.02mg/ml), S. aureus (zone of inhibition 0.8±0.03cm, MIC 0.09±0.02mg/ml), C. albicans (zone of inhibition 0.6±0.03cm, MIC 0.09±0.03mg/ml). Results demonstrated that these three N-alkylpyrrole chitosan derivatives exhibited improved potency and hence can have the more applicability as antimicrobials.

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