Antibacterial activity of sophorolipids produced by Candida bombicola on Gram-positive and Gram-negative bacteria isolated from salted hides / Daniel K. Y. Solaiman in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXI, N° 10 (10/2016)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXI, N° 10 (10/2016) . - p. 358-364 Titre : Antibacterial activity of sophorolipids produced by Candida bombicola on Gram-positive and Gram-negative bacteria isolated from salted hides Type de document : texte imprimé Auteurs : Daniel K. Y. Solaiman, Auteur ; Richard Ashby, Auteur ; Meral Birbir, Auteur ; Pinar Caglayan, Auteur Année de publication : 2016 Article en page(s) : p. 358-364 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antibactériens Bactéries à gram négatif Bactéries à gram positif Candida Cuirs et peaux -- Conservation Glycolipides Sophorolipides Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Salted hides and soaked hides treated with certain antibacterial agents, may still contain different proteolytic and lipolytic Gram-positive and Gram-negative bacteria that affect the quality of leather adversely. The prevalence of bacteria resistant to antimicrobial agents in the leather industry has drawn attention of scientists to search new and effective antimicrobial agents. Examination of antimicrobial glycolipids such as sophorolipids for their effectiveness against proteolytic and lipolytic hide-degrading microorganisms, may offer important information. Hence, we describe a research that evaluates the susceptibility of various hide-degrading bacteria to sophorolipids. These extracellular glycolipids were produced by fermentation using Candida bombicola ATCC 22214. Palmitic acid, stearic acid, and oleic acid were used respectively to produce SL-p, SL-s, and SL-o. The minimal inhibitory concentrations (MICs) of SL-p, SL-s, and SL-o against Gram-positive endospore-forming bacteria (Bacillus licheniformis, B. pumilus and B. mycoides), Gram-positive bacteria (Enterococcus faecium, Aerococcus viridans, Staphylococcus xylosus, S. cohnii and S. equorum), Gram-negative bacteria (Pseudomonas luteola, Enterobacter cloacae, E. sakazakii and Vibrio fluvialis), and mixed culture of these isolates were examined using an agar dilution method. The MICs of both SL-p and SL-o against the test bacteria were determined as 19.5 µg/mL, with an exception that E. cloacae was inhibited by SL-o at a MIC of 9.76 µg/mL. Although MICs of SL-p did not change against the test bacteria, the MICs of SL-s (ranging from 4.88 µg/mL to 19.5 µg/mL) changed according to species of the test bacteria. The lowest MICs of SL-s were found to be 4.88 µg/mL against B. licheniformis, B. pumilus, P. luteola, S. xylosus and B. mycoides. The MICs of SL-p, SL-s, and SL-o against the mixed bacterial culture were detected as the same (19.5 µg/mL). In conclusion, SL-p, SL-s, and SL-o inhibited the growth of 12 different hide bacteria and their mixed culture, and have broad-spectrum activity. The results obtained in the present study may be valuable for the development of SL-p, SL-s, and SL-o as antimicrobial surfactants in the preservation and soaking processes of hides and skins. Note de contenu : - Test microorganisms - Production of sophorolipids - Agar dilution method En ligne : https://drive.google.com/file/d/1_1T2en2bjAvf3Fync8UPQ5O5QWMSRfdx/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=27021 [article]

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Environmental effects on chrome-free leather / Cheng-Kung Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CI, N° 10 (10/2006)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CI, N° 10 (10/2006) . - p. 368-375 Titre : Environmental effects on chrome-free leather Type de document : texte imprimé Auteurs : Cheng-Kung Liu, Auteur ; Nicholas P. Latona, Auteur ; Richard Ashby, Auteur ; Keyi Ding, Auteur Année de publication : 2006 Article en page(s) : p. 368-375 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Chrome-free leather has gradually gained commercial importance, particularly for automobile upholstery applications. In many respects, however, chrome-free leather is inferior to chrome-tanned leather. UV and heat are known to be more detrimental to chrome-free leather than to chrome-tanned leather, especially in regard to the colorfastness of dyestuff and mechanical properties. Temperature, UV radiation, and humidity are key environmental factors that affect leather properties. The role of humidity and its interaction with UV radiation and temperature on leather properties, however, are not clear to the leather industry, and this information is needed for formulation of antioxidants that will protect chrome-free leather from UV and heat damage. Therefore, a systematic study was performed to formulate the relationship between these three environmental variables and resultant colorfastness and mechanical properties. A second order regression equation was derived to plot response surfaces that clearly illustrate the relationship between the environmental variables and colorfastness, as well as the resultant physical properties. Observations showed an intriguing interaction between humidity and radiation dosage. Measurements revealed that an increase in humidity resulted in a decrease in colorfastness and mechanical strength. However, after the UV radiation dosage reaches a certain level, an increase in humidity may actually help maintain both properties. Observation showed the stiffness decreased steadily with humidity, whereas the toughness index slightly increased with humidity. This study also used differential scanning calorimetry (DSC) to determine the denaturation temperature as a function of various environmental conditions. We observed a correlation between colorfastness and the denaturation temperature. En ligne : https://drive.google.com/file/d/1YrimELoNqwkDh2OJ98D14sqdial4H1DM/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3975 [article]

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Soaking formulations that can soften hardened bovine manure / Mila Aldema-Ramos in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVI, N° 7 (07/2011)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVI, N° 7 (07/2011) Titre : Soaking formulations that can soften hardened bovine manure Type de document : texte imprimé Auteurs : Mila Aldema-Ramos, Auteur ; Zerlina E. Muir, Auteur ; Richard Ashby, Auteur ; Cheng-Kung Liu, Auteur Année de publication : 2011 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Bovins -- Fumier Détergents Formulation (Génie chimique) Glycérine Le glycérol, ou glycérine, est un composé chimique de formule HOH2C–CHOH–CH2OH. C'est un liquide incolore, visqueux et inodore au goût sucré, utilisé dans de nombreuses compositions pharmaceutiques. Sa molécule possède trois hydroxyles correspondant à trois fonctions alcool responsables de sa solubilité dans l'eau et de sa nature hygroscopique. Un résidu glycérol constitue l'articulation centrale de tous les lipides de la classe des triglycérides et des phosphoglycérides. PROPRIETES PHYSIQUES : Le glycérol se présente sous la forme d'un liquide transparent, visqueux, incolore, inodore, faiblement toxique si ingéré (mais laxatif à haute dose), au goût sucré. Le glycérol peut se dissoudre dans les solvants polaires grâce à ses trois groupes hydroxyles. Il est miscible dans l'eau et l'éthanol ; et insoluble dans le benzène, le chloroforme et le tétrachlorométhane. Son affinité avec l'eau le rend également hygroscopique, et du glycérol mal conservé (hors dessicateur ou mal fermé) se dilue en absorbant l'humidité de l'air. - PROPRIETES CHIMIQUES : Dans les organismes vivants, le glycérol est un composant important des glycérides (graisses et huiles) et des phospholipides. Quand le corps utilise les graisses stockées comme source d'énergie, du glycérol et des acides gras sont libérés dans le sang. - DESHYDRATATION : La déshydratation du glycérol est faite à chaud, en présence d'hydrogénosulfite de potassium (KHSO3) et produit de l'acroléine - ESTERIFICATION : L'estérification du glycérol conduit à des (mono, di ou tri) glycérides. - AUTRES PROPRIETES : Le glycérol a un goût sucré de puissance moitié moindre que le saccharose, son pouvoir sucrant est de 0,56-0,64 à poids égal13. Le glycérol a des propriétés laxatives et diurétiques faibles. Comme d'autres composés chimiques, tels que le benzène, son indice de réfraction (1,47) est proche de celui du verre commun (~1,50), permettant de rendre "invisibles" des objets en verre qui y seraient plongés. Peaux brutes -- Nettoyage Peaux brutes -- Trempe Sophorolipides Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Many of the damaging problems in hides and leather industry, such as grain damage and weakening of the leather product, can originate from putrefaction due to microbial contamination and mechanical stress due to the heaviness and pressure of hard to remove adobe type manure on bovine hides. New washing methods are urgently needed to effectively clean raw hides for their storage and shipments. The amphiphilic property of detergents and the capability of glycerol to insert into the detergent micelles were investigated in the formulation of an ideal washing solution. Since the softening of the hardened manure is the key to its removal during the demanuring process, the initial experiments presented in this report were designed such that the changes in hardness of the manure balls were monitored using a texture analyzer. The work needed to cause the same amount of deformation on the manure sample was measured and compared before and after soaking in the respective formulations. Various detergent types such as anionic (SDS), nonionic (Tween 20 and TritonX-114) and zwitterionic (LDAO) are evaluated and compared to the biodegradable surfactant, sophorolipid (SL). The sophorolipid with the addition of recycled crude glycerol was observed to be more effective in softening the hardened manure samples and will be further studied for “adobe” type manure removal. En ligne : https://drive.google.com/file/d/1YfsD0Xfdlk9M0p7glc4zYWywlz9H1LVm/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=12030 [article]

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