Potencial dos resíduos agroindustriais para produção de bio-hidrogênio por fermentação escura: uma revisão sistemática

Abstract

The intensification of climate change and the need to decarbonize the energy matrix have driven the search for renewable hydrogen production routes. In this context, this study assessed the potential of Brazilian agro-industrial residues for biohydrogen production via dark fermentation through a systematic literature review. A structured search was carried out in the Scopus database using descriptors related to “biohydrogen”, “dark fermentation” and “agro-industrial waste”, considering experimental articles published between 2016 and 2025. By applying predefined eligibility criteria and the PRISMA 2020 flowchart, 628 records were initially identified, resulting in 14 studies included in the qualitative synthesis. These studies addressed lignocellulosic residues (straws, bagasse, corn cobs, coffee grounds, cassava peel), fruit and vegetable wastes (watermelon, melon, orange, banana and potato peels) and sugar-rich liquid streams such as molasses and vinasse, all of them relevant to the Brazilian agro-industrial context. Operating conditions ranged from mesophilic to thermophilic regimes (35–60 °C), pH between 5.0 and 7.8 and hydraulic retention times from 2 to 706 h, with volumetric hydrogen productivities varying from 0.01 up to about 33 L H₂•L⁻¹•d⁻¹; the highest values were generally associated with fruit residues and rice straw processed in high-rate reactors. Overall, thermal, acid/alkaline, oxidative and deep eutectic solvent pretreatments, combined with suitable hydrogen-producing microorganisms and careful control of pH and organic loading, were decisive for process performance. The review indicates that Brazilian agro-industrial residues hold substantial potential for biohydrogen production; however, technological consolidation of this route requires the development of lower-cost and greener pretreatments, high-rate continuous reactors, more pilot-scale and techno-economic studies, and regulatory frameworks that support the effective integration of biohydrogen into the national energy matrix.