Agricultural Biomass as a Resource for Biomaterials, Biofertilizers, and Bioproducts: A Systematic Review

This systematic review aimed to examine recent advances (2021–2025) in the conversion of agricultural biomass into biomaterials, biofertilizers, and bioproducts. Studies were included when addressing biomass types, pretreatment methods, conversion technologies, or resulting applications. Non-agricultural biomass, non-original research, and works outside the defined timeframe were excluded. Literature was identified in Scopus and Web of Science, complemented by Espacenet, Google Scholar, and institutional databases (USDA, FAO, IRRI, ABARES, UNICA, and CONAB, among others), totaling 108 documents referenced in this work. Risk of bias was minimized through predefined eligibility criteria and full-text assessment. Results were narratively synthesized, supported by figures and tables highlighting technological trends. Studies involving a wide range of agricultural biomasses (e.g., rice straw, corn stover, wheat straw, and sugarcane bagasse) were evaluated. Main outcomes included the development of bioplastics, biofoams, composites, hydrogels, bioceramics, biochar-based fertilizers, organic acids, enzymes, and green solvents. Evidence consistently indicated that pretreatment strongly influences conversion efficiency and that enzymatic and thermochemical routes show the highest potential for integrated biorefineries. Limitations included heterogeneity in biomass composition, variability in methodological quality, and scarcity of large-scale studies. Overall, findings underscore agricultural biomass as a strategic feedstock for circular bioeconomy models, with implications for sustainable materials, renewable energy, and low-carbon agriculture. Continued innovation, supportive policies, and improved logistics are essential for scaling biomass-based technologies.