Proteolytic extracts of three Bromeliaceae species as eco-compatible tools for leather industry
Most tanneries use high proportions of Na2S and CaO during the dehairing step, resulting in effluents of high alkalinity and large amounts of suspended solid, besides the risk of liberating the toxic H2S. Solid waste rich in protein is another environmental problem of tanneries. Enzymes are an interesting technological tool for industry due to their biodegradability, nontoxic nature, and nonpolluting effluent generation. In the leather industry, proteases have been chosen as a promising eco-friendly alternative to Na2S/CaO dehairing. Extracts with high proteolytic activity have been obtained from fruits of Bromeliaceae species: Bromelia balansae Mez (Bb), Bromelia hieronymi Mez (Bh), and Pseudananas macrodontes (Morr.) Harms (Pm). In this work, Bb, Bh, and Pm have been studied for application in the leather industry, focusing in their dehairing properties. Enzymatic activities were measured against collagen, keratin, elastin, and epidermis while a dehairing assay was performed by employing cowhide. All extracts showed similar activity on collagen and epidermis, while Bh and Pm were the most active against keratin at the same caseinolytic unit (CU) values; Bh was the only extract active against elastin. Bb (1 CU/ml), Bh (1.5 CU/ml), and Pm (0.5 CU/ml) were able to depilate cowhide. Desirable characteristics of dehairing were observed for all extracts since hair pores did not show residual hair, grain surface was clean and intact, and collagen fiber bundles of dermis were not damaged. In conclusion, results here presented show that proteolytic extracts of Bromeliaceae species are promising eco-compatible tools for leather industry.
KeywordsLime and sulfide-free dehairing Enzymatic dehairing Leather Plant proteases Bromeliaceae Protein waste
María Eugenia Errasti is member of the Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) Researcher Career. Laura María Isabel López is member of the National Council of Scientific and Technical Research (CONICET) Researcher Career. The present work was supported by grants from National Council of Scientific and Technical Research (PIP 00297) and Scientific Research Commission of the Province of Buenos Aires (PIT-AP-BA 2016). Authors want to thank Germán Mazzilli from technical staff of the Centro de Investigaciones de Tecnología del Cuero (CITEC), who performed the soaking process.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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