Comparative bibliometric analysis of biohydrogen and biomethane production from anaerobic fermentation of brewery byproducts

Abstract

Energy products derived from the anaerobic fermentation of agroindustrial byproducts can contribute to sustainable development by displacing fossil fuels and lowering greenhouse gas emissions. The byproducts generated in the beer industry (spent grains, spent yeast, and wastewater) could be a sustainable feedstock for anaerobic fermentation, producing biohydrogen and biomethane. This study presents a comparative bibliometric analysis of articles on biohydrogen and biomethane production from anaerobic fermentation of brewery byproducts published over a 10-year period. A systematic literature search identified 45 documents on biohydrogen and 78 documents on biomethane from brewery byproducts published between 2014 and 2023. The increasing number of documents published over that time can be attributed to the demand for suitable waste management options and the need to reduce greenhouse gas emissions. Analysis of the keywords listed by authors revealed that the main focus in biohydrogen production is the ‘biorefinery concept’. In contrast, ‘pretreatment’ and ‘microbial community’ are the key themes driving biomethane production and are important for future research. Biomethane production has been studied more often than biohydrogen production due to biomethane’s higher energy efficiency, denser energy sources, established infrastructure in many countries, and easier storage when compared with hydrogen. Finally, there is a lack of scientific studies of environmental assessment and technoeconomic analysis of biohydrogen and biomethane production from brewery byproducts.