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Hair saving unhairing process. Annex to part 5 (figures) - Characterisation of enzymatic preparations applied in soaking and unhairing processes / Carlos S. Cantera in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 3 (05-06/2003)
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Titre : Hair saving unhairing process. Annex to part 5 (figures) - Characterisation of enzymatic preparations applied in soaking and unhairing processes Type de document : texte imprimé Auteurs : Carlos S. Cantera, Auteur ; L. Goya, Auteur ; Betina Galarza, Auteur ; Maria Laura Garro, Auteur ; Laura M. I. Lopez, Auteur Année de publication : 2003 Article en page(s) : p. 89-90 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation
Epilage enzymatiqueIndex. décimale : 675 Technologie du cuir et de la fourrure Note de contenu : - Fig. 1 : Proteolytic activity as function of pH Enzymatic preparation : Alcamax Substrate: "Epidermis"
- Fig. 2 : Proteolytic activity as function of pH Enzymatic preparation : Pellvit Substrate: "Epidermis"
- Fig. 3 : Proteolytic activity as function of pH Enzymes: "Vegetal extract" Substrate : "Epidermis"
- Fig. 4 : Proteolytic activity as function of pH Enzymatic preperations : Alcamax, Pellvit and "vegetal extract" Substrate: "Keratin Azure"
- Fig. 5 : SDS-PAGE of Alcamax, Pellvit and "Vegetal extract"
- Fig. 6 : Isoelectric focusing and zymogram of Alcamax, Pellvit and "Vegetal extract"En ligne : https://drive.google.com/file/d/1nXQCLGCpCO5EUfvslgNxDmtWRcNBqq5v/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39780
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 3 (05-06/2003) . - p. 89-90[article]Hair saving unhairing process. Part 5 characterisation of enzymatic preparations applied in soaking and unhairing processes / Carlos S. Cantera in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 87, N° 2 (03-04/2003)
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Titre : Hair saving unhairing process. Part 5 characterisation of enzymatic preparations applied in soaking and unhairing processes Type de document : texte imprimé Auteurs : Carlos S. Cantera, Auteur ; L. Goya, Auteur ; Betina Galarza, Auteur ; Maria Laura Garro, Auteur ; Laura M. I. Lopez, Auteur Année de publication : 2003 Article en page(s) : p. 69-77 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Caractérisation
Epilage enzymatique
Peaux brutes -- TrempeIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Considering the importance that is attached to the characterisation of proteolytic enzymatic preparations employed in leather making, especially in the development of enzyme unhairing, our studies are aimed to develop a protocol of analysis that allows us to determine the behaviour of the enzymes on diverse protein skin substrates. In the protocol presented here it is important to highlight the incorporation of the so-called ‘epidermis substrate’, comprising the epidermis layer, hair and the root sheaths, as well as the procedure to assess enzymatic action on the proteoglycans.
On two of the substrates, “epidermis” and Hide Powder Azure, studies on activation/inhibition of the enzyme activity using components usually added in the soaking and unhairing processes was also carried out.
The protocol was applied to two commercial enzymatic preparations commonly used in leather processing, and to an extract of vegetable proteases that CITEC, jointly with LIPROVE, is applying in its investigation on enzyme unhairing.
The protocol developed is a useful tool to assist us in the design of ideal enzyme unhairing: that in which the enzymatic activity is orientated towards the components of the epidermis system, when their action on fibrous proteins – particularly collagen - is minimised or avoided and when the leathers developed have the desired properties.Note de contenu : - INTRODUCTION : Chromogenic substrates - The epidermis layer, hair and root sheaths : the ‘epidermis substrate’ - Activity on proteoglycans (PGs) and hide powder substrate
- OBJECTIVES
- MATERIALS AND METHODS : 1) Assessment of protein content - 2) Assessment of activities on different substrates : Non – keratin based substrates - Activity upon proteoglycans (PGs). Hide powder substrate - Keratin-based substrates - 3) Inhibition and activation tests - 4) Protein Profile. Electrophoresis in SDS/polyacrylamide gel (PAGE) - 5) Isoelectric Focusing (IEF) - Zymogram
- EXPERIMENTAL RESULTS
- PROTEOLYTIC ACTIVITY AGAINST DIFFERENT SUBSTRATES AND ACTIVATION AND INHIBITION ASSAYS
- ANALYSIS OF THE RESULTS : Activation and Inhibition Tests
- Table 1 : Proteolytic activity of the enzymatic preparations against different substrates
- Table 2 : Ranges of pH corresponding to 90% of the maximum activity for each one of the enzymatic preparations (maximum activity pH value is shown in brackets)
- Table 3 : Changes in the activity of Alcamax and Pellvit against the chromogenic substrates hide powder azure and ‘epidermis’ adding components used in soaking and unhairing processes (*)En ligne : https://drive.google.com/file/d/1lrLmDHNIHN7pji0LbISFfwO_LGJtTNU1/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39802
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 87, N° 2 (03-04/2003) . - p. 69-77[article]Hair saving unhairing process : Part 6 - Stratum corneum as a diffusion barrier : Chemical-mechanical injury of epidermis / Carlos S. Cantera in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 3 (05-06/2004)
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Titre : Hair saving unhairing process : Part 6 - Stratum corneum as a diffusion barrier : Chemical-mechanical injury of epidermis Type de document : texte imprimé Auteurs : Carlos S. Cantera, Auteur ; Maria Laura Garro, Auteur ; L. Goya, Auteur ; L. Barbeito, Auteur ; Betina Galarza, Auteur Année de publication : 2004 Article en page(s) : p. 121-131 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Couche cornée
Diffusion (physique)
Epilage
sulfite de sodium
Sulfitolyse
Surfactants
TrypsineLa trypsine (EC 3.4.21.4) est une enzyme digestive du suc pancréatique qui a pour rôle de digérer les protéines.
Elle est synthétisée par le pancréas sous forme de trypsinogène (proenzyme inactive), puis stockée dans les vésicules enzymatiques des cellules acineuses d'où elle est excrétée au moment de la digestion. L'activation du trypsinogène en trypsine est le résultat de l'hydrolyse d'un propeptide sous l'action de l'entérokinase ou par un effet d'autoactivation de la trypsine par elle-même. La cholecystokinine-pancréozymine active la sécrétion des enzymes (donc de la trypsine) dans le suc pancréatique.
La trypsine est une endoprotéase qui hydrolyse les liaisons peptidiques dans lesquelles un acide aminé basique (Lys-|-Xaa ou Arg-|-Xaa) engage sa fonction acide (sauf dans le cas où l'acide aminé suivant (schématisé ici par "Xaa") est une Proline). Elle coupe en C-terminal de ces acides aminés. En d'autres mots, elle transforme les chaînes polypeptides en chaînes protéiques plus courtes pour permettre la digestion. Efficace à pH 7,5 - 8,5, elle est inactivée et digérée en quelques heures à pH neutre (=7) dans l'intestin.
La trypsine participe à l'activation d'autres enzymes comme l'alpha-chymotrypsine par coupure hydrolytique de la chaîne polypeptidique du chymotrypsinogène.
Cette enzyme sert également lors de la 2e semaine du développement embryonnaire humain. Elle est sécrétée par le trophoblaste afin de digérer la zone pellucide entourant le blastocyste. Ce phénomène s'appelle l'éclosion.
UréeIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : In this new report of the series ‘Hair saving unhairing process’,we consider the epidermis as a diffusion barrier. The possible macro and micro routes of substance permeation across this tissue and the possible mechanisms of how to injure the stratum corneum and the intercellular inter-intra stratum adhesion are also described. A proposal related to the most important phases of unhairing is also considered, where the so-called Phase I : chemical-mechanical injury of the epidermis is highlighted. The sulphitolysis process, the action of trypsin, SDS, surfactants/solvents and urea are relevant factors to take into account in the above mentioned Phase I. Preliminary results, at laboratory scale, using ‘epidermis substrate’ and fresh hide are described. Note de contenu : - Objectives
- Epidermis structure, stratum corneum as a diffusion barrier
- Some remarks about trypsin activity : Sulphitolysis process - Action of urea - Action of surfactants - VIII Diffusion of substances across the epidermis - Results of preliminary trials - Trials with 'epidermis substrate' - Sulphitolysis reaction - Behaviour of surfactants/solvents - Trials with fresh hide
- Phases of the unhairing process
- Table 1 : Influence of Na2SO3, trypsin, surfactants/solvents and urea on "epidermis substrate"En ligne : https://drive.google.com/file/d/1Yblu9_geaYfAuc2I0KztnAv9j2_FeXiF/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39640
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 88, N° 3 (05-06/2004) . - p. 121-131[article]The diffusion barrier within the unhairing process / Carlos S. Cantera in WORLD LEATHER, Vol. 18, N° 6 (10/2005)
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Titre : The diffusion barrier within the unhairing process Type de document : texte imprimé Auteurs : Carlos S. Cantera, Auteur ; Maria Laura Garro, Auteur ; M. L. Goya, Auteur ; L. Barbeito, Auteur ; Betina Galarza, Auteur Année de publication : 2007 Article en page(s) : p. 29-32 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Epilage
Peaux brutesIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Hair-saving processes for bovine hides are being applied in tanneries in several countries to replace traditional hair burning systems. The factors that are taken into account when using this unhairing technique are :
- the need for a pelt that is suitable for the production of different types of leather
- a reduction in the effluent load arising from the beamhouse
- the recovery of the partially degraded hair as a solid waste with potential industrial applications
It is well known that the organic matter, the sulfide ion content and the presence of suspended solids in the liquid effluent is greatly dependant on the unhairing process employed. Within the sulfide unhairing system there are problems associated with toxicity, odour and effluent treatment.
Hydrogen sulfide is a highly toxic gas, and can be liberated from within the unhairing process and from effluent treatment. In extreme cases it has led to the death of workers, and in the wider environment creates an odour within the tannery surroundings which causes associated complaints. The acceptable maximum concentration in the work environment, in which a worker can remain for 8 hours/day and 5 days/a week, is 10 cm3 H2S/m3 (15 mg/m3) without suffering physical damage.
The enzymatic removal of intact hair offers a suitable alternative to destructive sulfide unhairing. However, interest in the enzyme unhairing process cornes and goes. This is because of difficulties in managing the process, mainly because the proteolysis cannot be accurately focused and controlled. Essentially, the enzyme activity is not restricted to the function of hair removal, but also affects the structure of the dermis. The grain layer is therefore partially digested hence there is a decrease in the quality of the grain structure in the final leather. Enzyme unhairing remains a fascinating concept, but is full of difficulties.
Nevertheless, the problems and costs of treating effluent to acceptable standards are considerable. If hair could be removed intact without using sulfide, then there would be a significant easing of techniques, capital equipment and power requirements to achieve discharge limits. In addition, the volume of sludge would be considerably reduced, with the hair remaining as a new clean raw material with many potential ourlets.Note de contenu : - The epidermis as a diffusion barrier
- The role of lipids within the epidermis
- The diffusion of substances across the epidermis
- Enhancers for penetration, or promoters for reactions : Sodium sulfite - Surfactants - Proteolytic enzymes - Trypsin - Urea - Organic solvents
- Phases of the unhairing processEn ligne : https://drive.google.com/file/d/14I1LkOfYwz-xkhH5GSFeR0kmgJqXd9Yb/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35688
in WORLD LEATHER > Vol. 18, N° 6 (10/2005) . - p. 29-32[article]Réservation
Réserver ce documentUnhairing of bovine skin with fungal enzymes by immersion and spread throughout the epidermis / Maria Laura Garro in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 103, N° 1 (01-02/2019)
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Titre : Unhairing of bovine skin with fungal enzymes by immersion and spread throughout the epidermis Type de document : texte imprimé Auteurs : Maria Laura Garro, Auteur ; Betina Galarza, Auteur ; Carlos Greco, Auteur ; Roque Hours, Auteur Année de publication : 2019 Article en page(s) : p. 28-34 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie)
Caractérisation
Cuirs et peaux de bovins
Diffusion (physique)
Enzymes fongiques
Epiderme
Epilage enzymatique
Immersion
Microscopie électronique à balayage
Travail de rivière (cuir)Index. décimale : 668.5 Parfums et cosmétiques Résumé : The use of enzymes during unhairing in the leather industry to partially reduce sulfide can decrease H2S emission to almost 50%. However the proteolysis needs to be controlled to prevent collagen damage. In bovine epidermis, the stratum corneum plays a crucial role as a hydrophobic barrier. In order to facilitate the diffusion of enzymes, it is necessary to generate channels through this barrier to allow enzymes pass without damaging the collagen. In an ideal enzymatic unhairing the proteolytic activity should be restricted to the basal lamina and pilosebaceous unit. During this experiment, fungal enzyme extracts (CE) were applied on bovine skin in the soaking and unhairing steps as part of the tanning process. The skin contacted with the solutions in two different ways : in direct contact with the epidermis (Mode I) and immersed in the solution (Mode II). Various keratinolytic fungi, previously isolated and selected from different soil samples were used : Neurospora crassa, Verticillium albo-atrum, Trichophyton ajelloi, Chrysosporium sp, Aspergillus sydowii, Paecilomyces lilacinus and Acremonium murorum. The fungal isolates were cultivated under solid state conditions using hair waste obtained from the hair-saving unhairing process as substrate. Enzyme extracts were characterized according to their keratinolytic and proteolytic activity and protein content. Once the immersion with fungal enzymes was finished, the treatment with N. crassa, T. ajelloi, Chrysosporium sp, A. sydowii and P. lilacinus, showed unhaired skin and epidermis removed. After the contact between the epidermis and fungal enzymatic extract of T. ajelloi empty hair follicles were observed. The morphological changes were studied with SEM (Scanning Electron Microscopy). Note de contenu : - INTRODUCTION : Epidermis - Basal lamina - Dermis - Objectives
- MATERIALS AND METHODS : Fungal strains isolates : culture and characterization - Assessment of protein content and proteolytic activity - Assay of proteolytic and keratinolytic activities - Mode I. Permeability assay of bovine skin epidermis with fungal enzyme extracts - Epidermis - Basal lamina - Dermis - Objectives
- MATERIALS AND METHODS : Fungal strains isolates : culture and characterization - Assessment of protein content and proteolytic activity - Assay of proteolytic and keratinolytic activities - Mode I. Permeability assay of bovine skin epidermis with fungal enzyme extracts - Control wells - Mode II. Assay with bovine skin immersed in the solutions - Control tubes - Scanning electronic microscopy (SEM) protocol
- RESULTS AND DISCUSSION : Assay of proteolytic and keratinolytic activities - SEM observationEn ligne : https://drive.google.com/file/d/1ym8R2Zy2q7HOf8f4HNvldFgm04pmesC6/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31790
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 103, N° 1 (01-02/2019) . - p. 28-34[article]Réservation
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