Biofertilizers in sustainable agriculture: mechanisms, applications, and future prospects

Abstract Background Biofertilizers are a sustainable alternative to chemical fertilizers, enhancing soil fertility, crop productivity, and environmental resilience. Plant growth-promoting rhizobacteria (PGPR) drive these benefits through nitrogen fixation (N 2 -fixation), nutrient solubilization (P, K, and Zn), phytohormone production, and stress mitigation. Despite their potential, widespread adoption is hindered by field performance variability, challenges in microbial survival, and insufficient regulatory frameworks. Main text This comprehensive review examines the mechanisms through which biofertilizers enhance agricultural sustainability, focusing on three key areas: (1) biological-mediated nutrient cycling (N 2 -fixation, phosphorus solubilization, and potassium mobilization), (2) phytohormone production and stress resilience, and (3) soil-plant-microbe interactions under climate variability. We analyze recent biotechnological advancements, including metagenomic approaches for strain selection, CRISPR-based microbial engineering, and nano-encapsulation techniques, which improve field performance and survival rates. Special emphasis is placed on the role of microbial consortia in climate-smart agriculture, particularly their capacity to mitigate greenhouse gas emissions while improving carbon sequestration and nutrient-use efficiency in major cropping systems. This review further explores the challenges of scaling these solutions, including inconsistencies in field performance and climatic conditions. Conclusion Addressing these opportunities and limitations, this study provides targeted recommendations for farmers, researchers, and policymakers. The adoption of biofertilizers requires coordinated efforts in standardization, policy development, and farmer education to realize their full potential for ensuring sustainable food production and environmental safety. Graphical abstract