Antifungal Potential of Hydrothermal Liquefaction Wastewater in Plant Protection

Abstract

This study investigates the antifungal potential of hydrothermal liquefaction (HTL) wastewater against Verticillium dahliae and its effects on the growth of pepper plants (Capsicum annuum L.). The HTL process generates wastewater containing various antimicrobial compounds, which can offer a sustainable alternative for plant protection. In this research, the biological control agent Trichoderma virens and HTL wastewater were applied both individually and in combination to assess their impact on plant growth and pathogen suppression. The results demonstrated that specific HTL wastewater treatments significantly enhanced root and shoot growth, biomass, and chlorophyll content in pepper plants. Plant growth observed in pathogen-free conditions may be related to the stimulation of plant physiology by biologically active components contained in wastewater, indicating a biostimulatory effect. Notably, the 4th wastewater mixture (wm) exhibited the highest efficacy, promoting plant development and mitigating the negative effects of V. dahliae. The combination of T. virens and wastewater also showed synergistic effects, reducing disease severity by up to 64% and improving plant biomass and structural parameters. Statistical analysis revealed significant differences among treatments, highlighting the potential of HTL wastewater as a natural and sustainable strategy for managing soil-borne pathogens. These findings suggest that integrating HTL wastewater with biocontrol agents could offer a promising approach to sustainable agriculture.