[article]
| Titre : |
Neutral protease assisted low-sulfide hair-save unhairing based on pH-sensitivity of enzyme |
| Type de document : |
texte imprimé |
| Auteurs : |
Yunhang Zeng, Auteur ; Qian Yang, Auteur ; Ya-Nan Wang, Auteur ; Jianfei Zhou, Auteur ; Bi Shi, Auteur |
| Année de publication : |
2016 |
| Article en page(s) : |
p. 345-353 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Chaux
Cuirs et peaux de bovins
Epilage enzymatique
Peptidases
Sulfure de sodium
|
| Index. décimale : |
675 Technologie du cuir et de la fourrure |
| Résumé : |
The mass transfer of protease in hide during enzymatic unhairing was first investigated by fluorescent tracer technique. It was found that the penetration rate of protease in hide was quite slow, and protease remained on the grain/papillary layer even after removal of hair, which is the main reason why enzymatic unhairing may cause grain damage or loose grain. But protease could effectively remove epidermis in a short time. From these phenomena, we developed an enzyme assisted low-sulfide hair-save unhairing (EALS unhairing) based on pH-sensitivity of neutral protease activity. To avoid risk of hide damage, soaked cattle hide (pH 8) was first treated with neutral protease (20 units/g hide) for 40 min at 22°C to cleave epidermis but not to unhair, and then 1% lime was immediately added both for inactivation of the neutral protease (pH>12) and for hair immunization. Finally, the hide was completely unhaired by using 0.8% sodium sulfide with intact hair shaft. The smartly controlled action of protease, as well as the synergistic effect of protease, lime and sulfide, ensured the complete removal of hair and epidermis with reduced offer of chemicals, and prevented pelts from defects. The crust leather processed by using EALS unhairing had a cleaner grain surface compared with that using conventional sulfide-lime unhairing. Additionally, the physical properties of the leather processed with EALS unhairing were comparable to those of conventional leather. Sulfide, total solids, suspended solids and chemical oxygen demand in the EALS unhairing effluent were markedly reduced due to a dramatic decrease in the input of sodium sulfide and lime as well as the recovery of hair. |
| Note de contenu : |
- EXPERIMENTAL : Materials - Visualization and quantification of protease in cattle hide during enzymatic unhairing - Effect of enzymatic unhairing time on damage to hide collagen - Effect of pH on proteolytic activity on neutral protease - Effect of pH on hydrolysable action of neutral protease on collagen fiber - Comparison between low-sulfide hair unhairing (LS unhairing) and enzyme assisted low-sulfide hair-save unhairing (EALS unhairing) - Comparison between conventional sulfide-lime unhairing and EALS unhairing
- RESULTS AND DISCUSSION : Penetration of protease in hide during enzymatic unhairing - Enzyme assisted low-sulfide hair-save unhairing (EALS unhairing - Comparison of conventional sulfide-lime unhairing and EALS unhairing |
| En ligne : |
https://drive.google.com/file/d/1bgCly-2SyNUBAWzubdqkDIuxdO4UeG2z/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26921 |
in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CXI, N° 9 (09/2016) . - p. 345-353
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Neutral protease assisted low-sulfide hair-save unhairing based on pH-sensitivity of enzyme in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CXI, N° 9 (09/2016)
