ORIGINAL RESEARCH article
Front. Nutr.
Sec. Nutrition and Food Science Technology
This article is part of the Research TopicTurning Fishery By-Products into Nutritional Gold: Strategies and InnovationsView all articles
Valorization of Fish-Processing By-Products through Combined Enzymatic and Microbial Hydrolysis: Nitrogen Recovery and Fertilizer Efficiency in Wheat
Provisionally accepted
Tamara Solis1Silvana Valdivia1Alejandra Vergara2Marcela Carvajal2Ignacio Seguel3
Pedro Luis Valencia4*- 1Programa de Doctorado en Biotecnología, Pontificia Universidad Católica de Valparaíso/Universidad Técnica Federico Santa María, Valparaíso, Chile
- 2Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Tecnica Federico Santa Maria, Valparaíso, Chile
- 3Future Botanics, Santiago, Chile
- 4Escuela de Alimentos, Pontificia Universidad Católica de Valparaíso, Valparaiso, Chile
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The bioconversion of fish byproducts has been evidenced as a sustainable process to convert food waste into high-value products. In the present study protein hydrolysates were produced from fish byproducts by different bioprocesses and evaluated as fertilizers in wheat (Triticum aestivum L.) on a nitrogen-equivalent basis. Fish byproducts were processed through grinding prior to bioconversion. Enzymatic hydrolysis was performed by Alcalase at 55°C, pH 6.5 and 3 h reaction, while microbial conversion was assessed by a lactic culture at 40°C, pH 6.5-and 10-days culture. Hydrolysates obtained by enzymatic and microbial bioconversion were evaluated as fertilizers by adding 30 mg after 7 and 14 days to wheat seeds sown under controlled conditions. Protease and microbial hydrolysis generated high concentrations of α-amino groups, yielding 100 mM and 170 mM, respectively. The combined process exhibited a synergistic effect, yielding 226 mM of α-amino groups and 33 % of protein recovery. Plant growth assays were conducted under controlled conditions using nitrogen-equivalent doses of each hydrolysate. Microbial and combined enzymatic-microbial hydrolysates generated an average plant length of 52 cm and 54 cm compared to 44 cm in control, while plants mass reached 1.7 g and 2.3 g with microbial and combined enzymatic-microbial hydrolysates compared to 0.7 g in control. Photosynthetic parameters remained within normal physiological ranges from 2.5 to 3.3 for PI and from 0.78 to 0.80 for Fv/Fm. The integration of enzymatic and microbial catalysis produced the most effective biostimulant activity, highlighting the value of combining enzymatic specificity with microbial metabolic versatility. These findings support fish-derived protein hydrolysates as efficient and eco-friendly fertilizers capable of improving plant growth while contributing to sustainable and integral utilization of natural resources.
Keywords: Biostimulant effect, Byproduct valorization, Fertilizers, Fish byproducts, Nitrogen recovery, Protein Hydrolysates
Received: 29 Nov 2025; Accepted: 02 Feb 2026.
Copyright: © 2026 Solis, Valdivia, Vergara, Carvajal, Seguel and Valencia. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Pedro Luis Valencia
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