Advancing plasma seed disinfection using a large-area pulsed wire-plate dielectric barrier discharge

Abstract

Seed production is a vital part of the global food supply chain. Seed surfaces are often contaminated with pathogenic fungal spores and bacteria, which cause plant diseases during germination. These pathogens prevent healthy crop growth and reduce yields by up to 40% in major crops. The future use of pesticides will be restricted by increasingly stringent regulations, while the demand for healthy crops continues to rise. Therefore, there is a growing need for eco-friendly technologies to inactivate seed-borne pathogenic microorganisms, without compromising seed quality. Cold atmospheric plasma (CAP) offers a promising alternative. Generated in ambient air, CAP is an ionized gas containing electrons, photons, ions, and reactive oxygen and nitrogen species (RONS). It does not leave toxic residues. Although CAP has demonstrated effective microbial inactivation at laboratory scale, its industrial implementation remains limited due to challenges in scalability, reliability and heat production. In this study, these limitations are addressed by developing and optimizing a wire-plate dielectric barrier discharge (DBD) for CAP seed disinfection, powered by high voltage pulses. The seed disinfection efficacy of the DBD was evaluated for cabbage and carrot seeds contaminated with bacteria (Xanthomonas campestris pv. campestris (Xcc) and Xanthomonas hortorum pv. carotae (Xhc)) and fungal spores (Alternaria brassicicola). Key parameters (such as treatment time, operating voltage and seed positioning) were investigated. The individual contribution of several plasma components (such as accelerated ions, RONS, pulsed electric fields) to seed disinfection was examined. Our results demonstrate that a large-area pulsed wire-plate DBD can achieve effective disinfection, while no reduction in seedling growth was observed. This highlights its potential as a scalable and sustainable alternative to conventional seed disinfection methods.