Pappalardo, Annabella (2026) Integrating Industrial By-Products and Beneficial Microorganisms for Innovative Agricultural Bioformulations. [Tesi di dottorato]

Documento PDF AnnabellaPappalardo_37.pdf Visibile a [TBR] Amministratori dell'archivio Download (1MB) | Richiedi una copia

Abstract

The increasing demand for sustainable agricultural practices and the transition towards a circular economy have stimulated growing interest in the development of biological alternatives to synthetic pesticides and in the valorisation of industrial by-products. In this context, the present PhD thesis investigated the potential of lignin-rich residues derived from second-generation bioethanol production and fatty acid (FA) by-products from herbicide manufacturing as innovative tools for crop protection and plant production. The first part of the research focused on the development of lignin-based microbial formulations containing beneficial microorganisms, particularly some Trichoderma strains. and Pseudomonas putida V01. Lignin was evaluated both as a substrate for solid-state fermentation (SSF) and as a co-formulant of formulation. The results demonstrated that lignin represents an effective support for microbial growth during SSF and an efficient carrier for the establishment of Trichoderma and Pseudomonas populations in soil. A bioformulation combining lignin and T. asperellum significantly increased the survival of tomato plants infected with Sclerotium rolfsii (more than 80%) under controlled conditions. Furthermore, the formulation promoted radicle and shoot development in Triticum aestivum seedlings and enhanced grain yield of Zea mays (+ 69 %) in a small-scale field trial conducted during the summer of 2024 at the experimental farm of the Department of Agricultural Sciences, University of Naples Federico II (Portici, Italy). The second part of the thesis investigated the biocontrol and plant growth promotion potential of P. putida V01. Its biological activity was assessed through a combination of in vitro assays, in vivo plant experiments, and metabolomic analyses. The strain exhibited promising antagonistic activity against fungal phytopathogens, while metabolomic investigations provided insights into the secondary metabolites potentially involved in its biocontrol mechanisms. Moreover, P.putida V01 increases shoot growth and chlorophyll content (+59%) in wheat seedlings under controlled conditions. The final part of the thesis evaluated the antifungal activity of pelargonic acid (FA9) and a mixture of short- and medium-chain fatty acids (FA5-9) obtained as by-products from the production of a pelargonic acid-based herbicide. The tested FA significantly inhibited the growth of economically important phytopathogenic fungi, including Fusarium verticillioides, reducing both mycelial growth (FA5-9 100% growth inhibition at 0.1% v/v, FA9 100% growth inhibition at 0.05% v/v) and spore germination (FA5-9 100% inhibition at 0.08 v/v, FA9 100% inhibition at 0.04 v/v). Moreover, FA5-9 and F9 exhibited enhanced antifungal activity when combined with 6-pentyl-α-pyrone (6-PP), a well-known Trichoderma metabolite with antifungal properties. Specifically, the combination of FA with 6-PP increased the antifungal efficacy of FA5-9 and F9 by approximately 20% compared with the FA applied alone. This combinatorial approach may allow a reduction in the concentration of individual compounds while maintaining or even enhancing their antifungal effectiveness. Overall, this work demonstrates that lignin-based microbial formulations and FA-based antifungal strategies represent promising approaches for the development of innovative bio-based products for crop protection. Beyond their biological efficacy, these solutions contribute to the valorisation of renewable resources and industrial residues, supporting the transition towards more sustainable and circular agricultural systems

Downloads

Actions (login required)

Modifica documento