Ammonia-generating coatings : truly green / Steve McDaniel in EUROPEAN COATINGS JOURNAL (ECJ), N° 1 (01/2020)  

[article]  inEUROPEAN COATINGS JOURNAL (ECJ) > N° 1 (01/2020) . - p. 42-46 Titre : Ammonia-generating coatings : truly green : Using cyanoacteria coatings to produce ammonia without the large energy overhead Type de document : texte imprimé Auteurs : Steve McDaniel, Auteur ; Brittney M. McInnis, Auteur ; Tyler W. Hodges, Auteur ; Lisa K. Kemp, Auteur Année de publication : 2020 Article en page(s) : p. 42-46 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Ammoniac Chimie écologique Cyanobactéries Revêtements organiques Index. décimale : 667.9 Revêtements et enduits Résumé : The Haber-Bosch process for producing ammonia has an enor-mous carbon footprint and there have been calls for low-energy alternatives. Cyanobacteria-based coatings that release ammonia without the high energy overhead may be the answer. Note de contenu : - Experimental - Coatings imbedded with cyanobacteria release ammonia - MSX boosts ammonia release - And so do high levels of ambient CO2 - A vision of the future - Fig. 1 : Coatings loaded with low biomass levels of Anabaena sp. (A) and N. muscorum (B) - Fig. 2 : Total ammonia washed from coatings loaded wihh low and high biomass levels as a function of coating surface area - Fig. 3 : Chlorophyll a per coating area as a measure of tell growth in coatings over lime - Fig. 4A : Quantification of ammonia washed from cyanobacteria-imbedded coatings standardised by biomass (chlorophyll a) - Fig. 4B: Chlorophyll a content of coatings as a function of coating area - Fig. 5A : Quantification of ammonia washed from N. muscorum-imbedded coatings incubated under ambient and high (1.5 %) CO, conditions - Fig. 5B : Quantification of ammonia washed from Anabaena-imbedded coatings incubated under ambient or high (1.5 %) CO, conditions - Fig. 6 : Diagram of coating lite cycle and products derived throughout the cycle En ligne : https://drive.google.com/file/d/1ikVwqvM3WrDt7wNgEeU9pP0lKSaQtKDD/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=33402 [article]

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Bio-based antimicrobial food packaging coatings / Brittney M. Mclnnis in COATINGS TECH, Vol. 15, N° 9 (09/2018)  

[article]  inCOATINGS TECH > Vol. 15, N° 9 (09/2018) . - p. 36-43 Titre : Bio-based antimicrobial food packaging coatings Type de document : texte imprimé Auteurs : Brittney M. Mclnnis, Auteur ; Tyler W. Hodges, Auteur ; Lisa K. Kemp, Auteur ; Jonathan D. Hurt, Auteur ; Steve McDaniel, Auteur Année de publication : 2018 Article en page(s) : p. 36-43 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Additifs biosourcés Alcool polyvinylique Aliments -- Emballages -- Aspect sanitaire Antimicrobiens Biomatériaux Chitosane Le chitosane ou chitosan est un polyoside composé de la distribution aléatoire de D-glucosamine liée en ß-(1-4) (unité désacétylée) et de N-acétyl-D-glucosamine (unité acétylée). Il est produit par désacétylation chimique (en milieu alcalin) ou enzymatique de la chitine, le composant de l'exosquelette des arthropodes (crustacés) ou de l'endosquelette des céphalopodes (calmars...) ou encore de la paroi des champignons. Cette matière première est déminéralisée par traitement à l'acide chlorhydrique, puis déprotéinée en présence de soude ou de potasse et enfin décolorée grâce à un agent oxydant. Le degré d'acétylation (DA) est le pourcentage d'unités acétylées par rapport au nombre d'unités totales, il peut être déterminé par spectroscopie infrarouge à transformée de Fourier (IR-TF) ou par un titrage par une base forte. La frontière entre chitosane et chitine correspond à un DA de 50 % : en deçà le composé est nommé chitosane, au-delà, chitine. Le chitosane est soluble en milieu acide contrairement à la chitine qui est insoluble. Il est important de faire la distinction entre le degré d'acétylation (DA) et le degré de déacétylation (DD). L'un étant l'inverse de l'autre c'est-à-dire que du chitosane ayant un DD de 85 %, possède 15 % de groupements acétyles et 85 % de groupements amines sur ses chaînes. Le chitosane est biodégradable et biocompatible (notamment hémocompatible). Il est également bactériostatique et fongistatique. Le chitosane est également utilisé pour le traitement des eaux usées par filtration ainsi que dans divers domaines comme la cosmétique, la diététique et la médecine. Emballages en matières plastiques Evaluation Peptides Revêtements -- Additifs Revêtements -- Analyse Tests microbiologiques Index. décimale : 667.9 Revêtements et enduits Résumé : The antimicrobial properties of two disparate bio-based coating additives were evaluated in a polyvinyl alcohol (PVA) food packaging coating for antimicrobial activity. Chitosan, a shrimp and crustacean shell derived polysaccharide, and an antimicrobial peptide were evaluated in a dissolvable food package coating for reductions in microbial growth after contacting agar patties serving as food simulants. Where the antimicrobial components of such packaging coatings are chosen to be generally recognized as safe by worldwide regulatory agencies, migration from the packaging into headspaces and food-contact surfaces can provide enhanced efficacy against foodborne pathogens, including viruses. The techniques and coatings presented in this article suggest that dramatic improvements in food safety can be achieved using coatings containing non-toxic bio-based biocides. Note de contenu : - MATERIALS AND METHODS : Reagents and bacterial strains - Preparation of coated films - Antimicrobial coated disk treatment of E. coli contaminated agar plates - Preparation of vacuum-sealed food simulants - EXPERIMENTS AND RESULTS : Clear disk antimicrobial assay - Moist-food simulant packaging study - Commercial packaging study at elevated concentrations and reduced coating thickness - Table 1 : Examples of recent outbreaks of foodborne illness in the United states - Table 2 : Colony counts and percent growth inhibition data for the high concentration PVA/chitosan/AMP7 on opalen and trayforma surfaces - Fig. 1 : Clear disk antimicrobial assays were done to rapidly determine synergistic, additive, or antagonistic effects of the studied bio-based antimicrobial agents - Fig. 2 : Vacuum sealed food-simulant packaging system having a bio-based antimicrobial coating. Diagram of the food-simulant packaging assembly, and a photograph of a fully assembled vacuum-sealed packaged food-simulant contamined with bacteria - Fig. 3 : Representative bacterial colony growth results upon contact with coated disks having increasing concentrations of AMP7 and/or chitosan (each test done in triplicate). Each bacterial colony that survived under the coated disk appears as a yellow dot in that area of the plate, while nearl complete-bacterial growth covers regions outside the disk - Fig. 4 : Dose responses of chitosan and AMP7, individually and in combination. The percent growth inhibition (as determined by reduced colony counts compared to PVA negative control) was used to calculate the dose response to coatings dosed with varying concentrations of AMP7 (A) and chitosan (B). A heatmap shows the response (as percent growth inhibition) to numerous combinations of different concentrations of AMP7 and chitosan (C). A contour map of synergy scores of the AMP7 and chitosan combinations, determined using the ZIP method, by which the positive scores (red) indicate synergy, the negative scores (green) indicate antagonism, and zero scores (white) indicate additive responses (D) - Fig. 5 : Resutts for vacuum-sealed bags containing PVA coatings dosed with AMP7 and chitosan combinations. Table of the colonycounts and percent growth inhibition data for vacuum-sealed samples treated with combination of chitosan and AMP7 in the coatings (Al. These data were used to calculate synergy scores using the Bliss model, which are visualized in a contour plot (B) - Fig. 6 : Antagonistic response confirmed with vacuum-sealed hag agar patty studies (each sample tested in triplicate) - Fig. 7 : Images of the vacuum-sealed agar pathos for the plain, uncoated films (WH column) and bio-based antimicrobial containing samples with 0.2-mil thick coating (middle column) 010.6-mil thick coating (right column) En ligne : https://drive.google.com/file/d/1DV-OBIZ8Ggr0Z9ILRvMRZIkqah-iNmWZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31235 [article]

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Proteins and peptides as replacements for traditional organic preservatives : Part I / Tyler W. Hodges in COATINGS TECH, Vol. 15, N° 4 (04/2018)  

[article]  inCOATINGS TECH > Vol. 15, N° 4 (04/2018) . - p. 44-50 Titre : Proteins and peptides as replacements for traditional organic preservatives : Part I Type de document : texte imprimé Auteurs : Tyler W. Hodges, Auteur ; Lisa K. Kemp, Auteur ; Brittney M. McInnis, Auteur ; Kyle L. Wilhelm, Auteur ; Jonathan D. Hurt, Auteur ; Steve McDaniel, Auteur ; James W. Rawlins, Auteur Année de publication : 2018 Article en page(s) : p. 44-50 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Additifs biosourcés Antibactériens Biomatériaux Conservateurs (chimie) -- Suppression ou remplacement Revêtements -- Additifs Index. décimale : 667.9 Revêtements et enduits Résumé : The utility of a high-throughput, spectrophotometric assay in screening over 23 enzyme and peptide-based additives against bacterial coating spoilage agents was evaluated. Candidate additives were then evaluated using ASTM D2574 for in-can coating spoilage challenges, and additives that may be used to substitute for traditional biocides were identified that eliminated recoverable bacterial growth. Note de contenu : - Reagents and bacterial strains - Measuring cell viability using XTT - Coating challenges - Table 1 : Bio-based additives tested in the XTT assay - Table 2 : Bacteria used for XTT and in-can coating challenges - 3. Coating used for in-can ASTM D2574 bacterial challenges - Fig. 1. Effects of various bio-based additives, alone and in combination, on the growth of a mixture in equal of A. faecalis, B. cereus, E. aerogenes, p. aeruginosa, p. fluorescens, and P. putida - Fig. 2. Effects of various bio-based additives, alone and in combination with traditional chemical-based biocides, on the growth of a mixture in equal parts of A. faecalis, B. cereus, E. aerogenes, p. aeruginosa, p. fluorescens, and P. putida - Fig. 3. Comparison of colony types present on plates from paint samples that scored 4 on day 7. Comparison of day 7 plates from the control acrylic latex samples (A) and acrylic latex + 0.05 mg/mL glucose oxidase + 2 mg/mL dextrose (B) shows that the paint with bio-based additive, though scorling 4 according to the ASTM guidelines, had at least one fewer colony type compared to the control En ligne : https://drive.google.com/file/d/1mlAEDD3RQVXuCMLrcz-E9cTDcX6cDyoO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=30519 [article]

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