Production of amino acid-rich fertilizer from sturgeon waste biosilage

Authors

1 Department of Biology, QaS.C., Islamic Azad University, Qaemshahr, Iran

2 Caspian Sea Ecology Research Institute, Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research, Education and Extension Organization (AREEO), Sari, Iran

3 Department of Bioscience and Technology, Faculty of Basic Sciences, Islamic Azad University, Sari Branch, Sari, Iran

Abstract

Fish processing generates substantial amounts of organic waste, particularly from high-value species like sturgeon. Transforming these nutrient-rich wastes into value-added products, such as biosilage and amino acid fertilizers, offers an environmentally friendly solution that aligns with the principles of a circular bioeconomy. This study aimed to produce biosilage from sturgeon waste through microbial fermentation and to evaluate its potential for amino acid fertilizer production. Initially, biosilage was prepared and subjected to quality control through assessments of proximate composition and microbial indices. Molecular identification of the dominant fermentative bacteria using 16S rRNA sequencing revealed the presence of Bacillus cereus (99.5% similarity; Accession No. KP940382.1), as well as lactic acid bacteria, including Lactobacillus plantarum, L. acidophilus, and L. pentosus. The biosilage demonstrated significantly higher levels of protein (67.7%), lipid (14.06%), and ash (11.26%), along with lower moisture content (6.98%) compared to raw waste (p<0.05). Microbial analysis confirmed the safety of the biosilage, showing high levels of lactic acid bacteria (6.48 log CFU/g) and the absence of Escherichia coli and Salmonella typhimurium. After quality control, an amino acid fertilizer was produced from the biosilage. The amino acid profile revealed total and free amino acid contents of 14.02% and 8.08%, respectively, with glutamic acid  and leucine being the most abundant. Additionally, elemental analysis showed a balanced nutrient content, including total nitrogen (3.56%), phosphorus (0.81%), potassium (0.34%), and organic matter (17.92%). In conclusion, the stepwise conversion of sturgeon waste into biosilage and amino acid fertilizer represents eco-friendly strategy for waste valorization.

Keywords

Iranian Journal of Fisheries Sciences
Volume 25, Issue 3
May 2026
Pages 509-524

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