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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A new fungal isolates applicated to bovine skin in beamhouse processes

Galarza, Betina, Garro, M. L., Ferreri, N., Elíades, L., Hours, R. 28 June 2019 (has links)
Content: Beamhouse area is an important step in leather technology, either in the final quality of the leather or in the contribution to the contamination of effluents. In unhairing process, the use of enzymes as sulphide assistants can reduce sulfhidric gas emissions to reach permitted levels for health. The characterization of enzymatic extracts allows controlling the proteolysis mechanism so that its action does not attack the reticular structure. A new fungal enzyme extracts were applied on submerged bovine skin in the soaking and unhairing steps. Fungal strains were isolated from alkaline soils of coast of Buenos Aires province and enzymatic extracts (EE) were obtained by submerged culture with bovine hair waste from hair-saving unhairing process as inducer in the production of keratinolytic enzymes. This activity was determined by quantitative test and the most productive strains were selected: Clonostachys rosea (CR), Emericellopsis minima (EM), Paecilomyces lilacinus (PL), Penicillium sp (Psp), Fusarium oxysporum (FO), Acremonium sp (A) and an unidentified filamentous fungus strain with sterile yellow mycelium (SYM). EE were tested at laboratory scale on submerged bovine skin with biocide 0,2% w/w wet skin, anionic 0,1% and non-ionic 0,5% tensioactives in soaking and unhairing respectively and incubated 48 h at 37°C in shaking thermostatic bath. Controls were tested in the same conditions without EE. Morphological changes in the skin were observed by scanning electron microscopy (SEM). Pieces of bovine skin were fixed, post-fixed in formaldehyde 4% and dehydrated in alcohol solutions, treated by critical point drying, metalized and analyzed in SEM. It was observed with FO, EM and A extracts empty hair follicles, absence of epidermis, papillary layer of dermis exposed, hairs enclosed by detached hair follicle sheaths and collagen fibers without characteristic patterns. With PL and SYM EE some hairs were detached while Psp and CR EE did not produce changes. In control samples epidermis and hair without modification were observed. In the quantitative test, keratinolytic activities increased in the following order: A<PL<Psp<CR<FO<SYM. Submerged culture with keratin as inductor produced keratinolytic enzymes useful for unhairing step. Fusarium oxysporum extract showed the greatest effect on the skin, thus the relationship between keratinolytic activity and depilatory effect was found. However, it is necessary to find the optimal conditions to avoid the damage of collagen and enable its application as a sustainable technology. Take-Away: A new fungal isolates applicated to bovine skin in beamhouse processes

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