{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T05:03:51Z","timestamp":1789707831583,"version":"4.0.1"},"reference-count":53,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T00:00:00Z","timestamp":1789084800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100025014","name":"Instituto Valenciano de Competitividad Empresarial","doi-asserted-by":"crossref","award":["IMI DSB\/2026\/10, AQUA2VAL II"],"award-info":[{"award-number":["IMI DSB\/2026\/10, AQUA2VAL II"]}],"id":[{"id":"10.13039\/501100025014","id-type":"DOI","asserted-by":"crossref"}]},{"award":["IMI DSB\/2026\/10, AQUA2VAL II"],"award-info":[{"award-number":["IMI DSB\/2026\/10, AQUA2VAL II"]}],"id":[{"id":"https:\/\/ror.org\/01svxr124","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>The recovery of bioactive compounds from industrial wastewaters is a key strategy for improving resource efficiency and reducing the environmental impact of high-load effluents. In this work, two protein-rich tannery wastewater streams with different origins and compositions, unhairing\u2013liming wastewater and lime-fleshing wastewater, were comparatively evaluated as secondary raw materials for the production of amino acid-based protein hydrolysates with potential biostimulant activity. Both streams were characterised in terms of physicochemical composition, mineral content and amino acid profile, and subsequently subjected to a comparative sequential enzymatic hydrolysis approach using endo- and exo-proteolytic enzymes. Alcalase, followed by Pancreatin, was selected as the most effective enzymatic system for both streams, although different optimal enzyme loadings were required depending on the wastewater composition. For unhairing\u2013liming wastewater, the optimal conditions were 1.5% Alcalase and 1.0% Pancreatin, yielding 70.76 \u00b1 1.95% hydrolysate, 80.87 \u00b1 1.98% protein recovery and 11.42 \u00b1 1.03% free amino acids. For lime-fleshing wastewater, 0.7% Alcalase and 1.0% Pancreatin provided 98.42 \u00b1 1.97% yield, 92.19 \u00b1 1.92% protein recovery and 16.97 \u00b1 0.98% free amino acids. The two hydrolysates showed differentiated amino acid profiles, reflecting the keratin- and collagen-derived nature of the original streams. Germination assays indicated a growth-stimulating effect of the hydrolysates, increasing seed growth by up to 20.7% for the unhairing\u2013liming wastewater hydrolysate at 0.10% (w\/v) and by up to 27.1% for the lime-fleshing wastewater hydrolysate at 0.07% (w\/v). These results demonstrate that enzymatic hydrolysis can be an effective and environmentally friendly route for converting tannery wastewaters into value-added bio-based products for agricultural applications, while also highlighting the industrial relevance of adapting the enzymatic process to the origin, composition and protein accessibility of each wastewater stream.<\/jats:p>","DOI":"10.3390\/molecules31183213","type":"journal-article","created":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T14:39:24Z","timestamp":1789137564000},"page":"3213","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Sequential Enzymatic Bioprocessing of Protein-Rich Unhairing\u2013Liming and Lime-Fleshing Tannery Wastewater for the Production of Amino Acid-Based Plant Biostimulants"],"prefix":"10.3390","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8062-489X","authenticated-orcid":false,"given":"Henoc","family":"P\u00e9rez-Aguilar","sequence":"first","affiliation":[{"name":"INESCOP, Footwear Technology Centre, Pol. Ind. Campo Alto, C\/Alemania, 102, 03600 Elda, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2885-9231","authenticated-orcid":false,"given":"V\u00edctor M.","family":"Serrano-Mart\u00ednez","sequence":"additional","affiliation":[{"name":"INESCOP, Footwear Technology Centre, Pol. Ind. Campo Alto, C\/Alemania, 102, 03600 Elda, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5471-9318","authenticated-orcid":false,"given":"Carlos","family":"Ruzafa-Silvestre","sequence":"additional","affiliation":[{"name":"INESCOP, Footwear Technology Centre, Pol. Ind. Campo Alto, C\/Alemania, 102, 03600 Elda, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2085-1211","authenticated-orcid":false,"given":"Alberto","family":"Vico","sequence":"additional","affiliation":[{"name":"INESCOP, Footwear Technology Centre, Pol. Ind. Campo Alto, C\/Alemania, 102, 03600 Elda, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0165-7752","authenticated-orcid":false,"given":"Mar\u00eda Dolores","family":"Romero-S\u00e1nchez","sequence":"additional","affiliation":[{"name":"INESCOP, Footwear Technology Centre, Pol. Ind. Campo Alto, C\/Alemania, 102, 03600 Elda, Alicante, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Millati, R., Cahyono, R.B., Ariyanto, T., Azzahrani, I.N., Putri, R.U., and Taherzadeh, M.J. (2019). Agricultural, Industrial, Municipal, and Forest Wastes. Sustainable Resource Recovery and Zero Waste Approaches, Elsevier.","DOI":"10.1016\/B978-0-444-64200-4.00001-3"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Kaza, S., Yao, L.C., Bhada-Tata, P., Van Woerden, F., and Levine, D. (2018). What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050, World Bank.","DOI":"10.1596\/978-1-4648-1329-0"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Xu, L., and Geelen, D. (2018). Developing Biostimulants from Agro-Food and Industrial By-Products. Front. 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