Sviluppo di biofertilizzanti batterici e/o fungini utili verso un' agricoltura sostenibile

The growing pressure on global food systems, driven by climate change, soil degradation, and the increasing demand for agricultural sustainability, calls for innovative approaches that reconcile productivity with environmental integrity. Microbial biotechnology offers a promising pathway toward this goal by harnessing beneficial plant–microbe interactions to enhance nutrient efficiency, stress tolerance, and soil functionality. This doctoral thesis investigates the development, evaluation, and industrial scalability of bacterial and fungal biofertilizers as biologically based tools for sustainable agriculture, integrating agroecological principles with applied microbiology and bioprocess engineering. The research is structured around a multidisciplinary framework combining conceptual analysis, controlled experiments, and technological validation. The first part provides a comprehensive introduction to current sustainability paradigms, agroecology, and soil microbiome management, framing microbial inoculants within the transition from input-intensive to knowledge-intensive agriculture. The experimental sections assess the effects of selected beneficial microorganisms, including arbuscular mycorrhizal fungi, plant growth-promoting bacteria, and fungal biocontrol agents, on crop growth, nutrient uptake, secondary metabolite production, and disease suppression under both abiotic and biotic stress conditions. Case studies include drought-stressed medicinal plants, Fusarium basal rot in onion, and the functional performance of multi-strain microbial consortia. A central focus of the thesis is the technological dimension of microbial biofertilizers. Co-cultivation strategies, formulation types, shelf-life stability, and carrier systems are systematically evaluated to identify critical factors affecting microbial viability and field applicability. Furthermore, scale-up challenges were assessed by demonstrating the transfer of optimized fermentation processes from laboratory scale to industrial bioreactors, highlighting process control, reproducibility, and quality assurance. Overall, this thesis contributes original knowledge to the field of sustainable agriculture by bridging fundamental plant–microbe interactions with industrial biofertilizer production, supporting the development of scalable, effective, and environmentally sound microbial solutions for modern cropping systems.