Bacterial and fungal damage in leather / Joseph Ondari Nyakundi in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 8 (08/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 8 (08/2023) . - p. 327-339 Titre : Bacterial and fungal damage in leather Type de document : texte imprimé Auteurs : Joseph Ondari Nyakundi, Auteur Année de publication : 2023 Article en page(s) : p. 327-339 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Biodégradation Cuirs et peaux -- Analyse Cuirs et peaux -- Détérioration Détérioration bactérienne Détérioration fongique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Microbial degradation leads to significant loss of quality and economic value by the tanner. This damage cannot be reversed as it involves the degradation of the collagen and elastin fibers, which are important proteins in the leather-making process. It is, therefore, important to carefully monitor the after-slaughter, curing, beamhouse and posttanning processes to prevent this type of damage. This is only possible if you can identify the signs and/or defects caused by bacteria and fungi as early as possible and put in place corrective measures to halt any further or future damage. This study evaluated various techniques for identifying bacterial and fungal damage in leather, including visual inspection, smell, feel, microscopy, and culturing techniques. Samples of cured hides and leather obtained from different sources in the USA were subjected to these techniques to determine the presence of these microbes or to identify their damage. The results highlight various defects and indicators that point to various microbial causes. A combination of visual inspection, microscopy, and culturing techniques can provide hides and skins sellers, packers, and tanners with reliable and accurate identification techniques for identifying early signs of damage. While microscopy was sufficient to observe fungal growth and bacterial damage, culturing was more reliable for identifying the bacterial causative agents. This study highlights the importance of implementing routine inspections and monitoring to prevent continued microbial damage to hides to ensure the quality of the leather. Note de contenu : - INTRODUCTION : Biodeterioration in leather - Impact of biodeterioration on the quality of leather - MATERIALS AND METHODS : Materials - Methods : Custuring techniques - Visual examination - Microscopic examination - RESULTS AND DISCUSSION : Culturing techniques - Visual inspection and microscopy - Table 1 : Biological activity reaction test results after 8 days - Table 2 : Paddle test results after the 48 Hr. - Incubation period - Table 3 : Total aerobic bacteria testing result after 48 hour - Table 4 : Yeast and mold testing results after 5 days - Appendix 1 : Paddle test DOI : https://doi.org/10.34314/jalca.v118i8.8090 En ligne : https://drive.google.com/file/d/1G_Sd25joYXHJN7SPlNKK1QUnlgTwUnBu/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39672 [article]

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Fungal biotransformation of bovine hair : Part 1 - Isolation of fungus with keratinolytic activity / B. C. Galarza in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 3 (05-06/2004)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 88, N° 3 (05-06/2004) . - p. 93-98 Titre : Fungal biotransformation of bovine hair : Part 1 - Isolation of fungus with keratinolytic activity Type de document : texte imprimé Auteurs : B. C. Galarza, Auteur ; L. M. Goya, Auteur ; Carlos S. Cantera, Auteur ; Maria Laura Garro, Auteur ; H. E. Reinos, Auteur ; Laura M. I. Lopez, Auteur Année de publication : 2004 Article en page(s) : p. 93-98 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bovins Détérioration fongique Poils -- Biodégradation Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The present study reports on the results of the “fungal biodegradation” of “hair waste” in a static solid medium using previously isolated strains of Trichophyton ajelloi and Fusarium oxysporum. The main purpose of the research programme is to upgrade the hair by biodegradation, to consider it as a raw material instead of the current modality of “throwing away” proteins to landfill and to its reuse in agricultural technology, directly or after composting and applying earthworms to generate an organic fertilizer (“vermicompost”). The fungal activity on the hair gives a degraded organic material and an extract with a pool of proteases with, amongst others, keratinolytic activity,. The enzyme activities expressed by the fungal extract are evaluated against soluble, insoluble, synthetic, and skin protein component substrates. Relationships between the different specific activities are defined to evaluate and predict the possible behaviour of the fungal extracts in the beamhouse processes. Note de contenu : - Solid state culture - Objectives - Experimental Development : Materials and Methods - Protocol of the analysis for activity assessment - Results and Discussion : Assessment of enzymatic activities of crude extracts - Aminopeptidase Activity. Determination of kinetic constants - Assessment of the degree of hair digestion - Protein profile and Isoelectric Focusing (IEF) - Zymogram - Comments on mechanisms of fungal digestion of hair - Fungal extracts in the soaking, unhairing and bating processes. Possible applications - Table 1 : Proteolytic activity of the fungal extracts of the different substrates - Table 2 : Activity Relationships for Trichophyton ajelloi and Fusarium oxysporum fungal extracts En ligne : https://drive.google.com/file/d/1Mrbx0x1BGf1ZNG_jsl1LMyTL1SX9KH-J/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39634 [article]

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Fungal biotransformation of bovine hair. Part 2 : Biomass and proteases produced as a function of incubation time. Assessment of hair waste digestion / B. C. Galarza in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 90, N° 4 (07-08/2006)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 90, N° 4 (07-08/2006) . - p. 169-172 Titre : Fungal biotransformation of bovine hair. Part 2 : Biomass and proteases produced as a function of incubation time. Assessment of hair waste digestion Type de document : texte imprimé Auteurs : B. C. Galarza, Auteur ; L. M. Goya, Auteur ; M. L. Garro, Auteur ; J. Mercerat, Auteur ; R. A. Hours, Auteur ; Carlos S. Cantera, Auteur Année de publication : 2006 Article en page(s) : p. 169-172 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cuirs et peaux Cystine La cystine est un acide aminé composé de deux unités cystéine liées par un pont disulfure. Déchets -- Valorisation Détérioration fongique Epilage Microscopie Peptidases Poils -- Biodégradation Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Unlike the conventional hair-saving unhairing processes, the modern processes considerably reduce the organic load from the beamhouse liquid effluent and yet a partially degraded 'hair waste' is generated, which has to be properly disposed of. It is estimated that a tannery processing 25 ton of salted cow hides will recover about 2.5 ton of wet hair per day. As was mentioned in the first part of the series 'Fungal biotransformation of bovine hair' the aim of our activities is to produce structural changes in the ‘hair waste’ using it as a solid substrate for the growth of the fungal species Trichophyton ajelloi and therefore weakening the keratinís resistance to hydrolysis processes. A strain of this microorganism, which was isolated from a Yak yard, has proved to be able to generate an enzymatic system capable of degrading hair keratin by means of specific proteases: the keratinases. Fungal activity also gave place to an enzymatic extract with activity upon the protein substrates of the epidermis and dermis of bovine hide. It should be noted that reports on fungal pathogenesis indicated that Trichophyton ajelloi presents no pathogenicity for men or animals. Upgrading the 'hair waste' by fungal biotransformation implies considering it as a raw material and not taking the current modality of 'throwing away proteins' to the soil (cost of transport and disposal of waste in landfills). Biodegradation offers on the one hand the attractive concept of 'feedback' since hair is the solid substrate upon which fungi act generating a degraded organic waste and a protein extract with proteolytic activity (keratinolytic among others) whose unhairing activity is evaluated. On the other hand an intermediate stage would be generated in the transformation of the ‘hair waste’ with potential uses in vermiculture and vermicompost. Note de contenu : - OBJECTIVES - MATERIALS AND METHODS : Culture conditions of the microorganism - Analytical techniques - Assessment of the degree of digestion of the ‘hair waste’ - RESULTS AND DISCUSSION : Microscopy observations - Assessment of digestibility - Cystine assessment in the ultrafiltered crude extract - Final remarks - Table 1 : Hair digestibility En ligne : https://drive.google.com/file/d/1fYmDuf6dOPGGOroT0Iv-Raf9r9NFKTRb/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39116 [article]

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Fungal deterioration on ancient leather artifacts / Zonghuan Ba in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXVIII, N° 12 (12/2023)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXVIII, N° 12 (12/2023) . - p. 529-535 Titre : Fungal deterioration on ancient leather artifacts Type de document : texte imprimé Auteurs : Zonghuan Ba, Auteur ; Zhang Mingrui, Auteur ; Yulong Chen, Auteur ; Yizhe Cao, Auteur ; Zhuofan Hu, Auteur Année de publication : 2023 Article en page(s) : p. 529-535 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Antiquités (objets anciens) -- Analyse Cuirs et peaux -- Détérioration Détérioration fongique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Fungal deterioration of ancient leather artifacts is a significant problem for museums and archives, as it might cause significant damage to the valuable cultural heritage. The growth of fungi on these artifacts is affected by such environmental factors as temperature, relative humidity, pH, and light exposure. The environmental factors that contribute to fungal growth and the impact fungi on the deterioration of ancient leather artifacts are discussed here. An overview is summarized on the strategies to prevent and control fungal deterioration, including the environmental control, the use of biocides, and conservation treatments, which is proposed to provide a valuable guidance for the preservation of ancient leather artifacts. Note de contenu : - Factors affecting fungal growth - Fungi on ancient leather artifacts - Biodeterioration mechanisms of leather by fungi - Conservation and restoration - Table 1 : The optimal temperature of Aspergillus, Penicilium, Eurotium and Cladosporium - Table 2 : Fungi found on ancient leather artifacts associated with leather process DOI : https://doi.org/10.34314/jalca.v118i12.8261 En ligne : https://drive.google.com/file/d/1W-fjSYxQh0U36AvB7mVi1sglbZjpCM6d/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40272 [article]

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