Enzymes are widely used in biofuels, food, and pharmaceuticals.

Fermentation is an oxygen-free biological process that produces hydrogen, a clean, renewable energy source with the potential to power a low-carbon economy. Bibliometric analysis is crucial in academic research to evaluate scientific production, identify trends and contributors, and map the development of a field, providing valuable information to guide researchers and promote scientific innovation. This review provides an advanced bibliometric analysis and a future perspective on fermentation for hydrogen production. By searching WoS, we evaluated and refined 62,087 articles to 4493 articles. This allowed us to identify the most important journals, countries, institutions, and authors in the field. In addition, the ten most cited articles and the dominant research areas were identified. A keyword analysis revealed five research clusters that illustrate where research is progressing. The outlook indicates that a deeper understanding of microbiology and support from energy policy will drive the development of hydrogen from fermentation.

This study aims to explore technological advances and prospects in phenol treatment by providing a detailed bibliometric survey of wastewater treatment applications, highlighting innovative advances in research. Using the Web of Science database, we identified 79,104 articles from 2003 to 2023, later refined to 1848. The keywords were used for the initial search: “phenol”, “wastewater”, “degradation”, “treatment” and “removal”. The bibliographic review details the occurrence of journals, authors, newspapers, countries, institutions, keywords, highly cited articles, and prominent predominant research fields. In particular, the field of “Engineering” was responsible for 32% of the published articles, followed by “Ecology of Environmental Sciences” (25%) and “Chemistry” (12%). In addition, a keyword analysis revealed five major groups of clusters that indicate where the research is progressing. This aspect is crucial for understanding the evolution and perspectives of research interests over time. Therefore, future research in the field should prioritize wastewater treatment and feedstock diversification. This focus is essential to address significant challenges, such as production costs, stability, and durability of treatment processes. Graphical Abstract