Research Trends in the Valorisation of Potato Peels for Fermentative Biohydrogen Production: A Bibliometric Analysis (2015-2025)

<title>Abstract</title> <p> <bold>Purpose</bold> This study evaluates global research trends, research focus, and thematic developments in biohydrogen production from potato peels (PP) through a bibliometric analysis. Specifically, it examines the evolution of PP-based biohydrogen research from 2015 to 2025 and identifies major research trends, influential contributors, and emerging thematic directions. <bold>Methods</bold> A bibliometric analysis was conducted using publications retrieved from the Scopus database. A search performed on 16 June 2026 identified 39 records published between 2015 and 2025. Following screening and eligibility assessment, 24 publications from 11 countries were included. Data were analysed using VOSviewer version 1.6.20 to evaluate publication trends, country and journal contributions, citation performance, keyword co-occurrence networks, and thematic evolution. <bold>Results</bold> Research output increased steadily over the study period, particularly after 2020, reflecting growing interest in waste valorisation and renewable hydrogen production. China was the most productive country, while South Korea achieved the highest citation impact. <italic>Bioresource Technology</italic> emerged as the leading publication outlet. Citation and keyword analyses identified 4 dominant research themes: Fermentative Biohydrogen Production and Process Enhancement from Organic Waste; Dark Fermentation Optimisation for Sustainable Hydrogen Production from Biomass Residues; Microbial Activity, Enzymatic Hydrolysis and Feedstock Characterisation; and Anaerobic Bioreactor Systems and Hydrogen Yield Evaluation. The field has progressed from feasibility studies towards process optimisation, reactor development, predictive modelling, and integrated biorefinery approaches, demonstrating an increasing emphasis on sustainable biomass valorisation and process intensification. <bold>Conclusion</bold> Research on PP-based biohydrogen production has evolved into a mature and increasingly interdisciplinary field that supports circular bioeconomy and waste valorisation objectives. This study provides a comprehensive overview of the intellectual structure and emerging research directions in the field. It highlights opportunities for future investigations across multiple bibliographic databases and emphasises the development of scalable, integrated biorefinery systems for sustainable biohydrogen production. </p>