Development of non-thermal plasma sterilization technology for hydroponic nutrient solution for measures against wilt disease in a plant factory

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05902
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 41040:Agricultural environmental engineering and agricultural information engineering-related
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: Yasui Shinji 名古屋工業大学, 工学(系)研究科(研究院), 教授 (30371561)
• Co-Investigator(Kenkyū-buntansha): 庄子 和博 一般財団法人電力中央研究所, エネルギーイノベーション創発センター, 上席研究員 (10371527)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 大気圧プラズマ / 殺菌 / 培養液 / 液中プラズマ / 植物工場 / 萎凋病

Outline of Final Research Achievements

We have developed a sterilization technology using low temperature atmospheric pressure plasma of a nutrient solution for nutrient thin film hydroponics in a plant factory. We have firstly shown that Fusarium oxysporum and Pythium aphanidermatum, which are the pathogenic bacteria of wilt disease in thin-film hydroponics such as spinach in summer, can be completely sterilized by plasma irradiating to the nutrient solution. The sterilization mechanism was elucidated by various control experiments, and it was clarified that the OH radical generated in the solution is an extremely large sterilization factor. Bacterial contamination of the culture medium invades from the roots with human intervention during planting of seedlings. In a demonstration experiment using spinach hydroponics, it was clarified that wilt disease can be controlled by short-term plasma irradiation of about 5 minutes both before and after planting seedlings.

Free Research Field

電力工学

Academic Significance and Societal Importance of the Research Achievements

培養液中へのプラズマの直接照射により，薄膜水耕栽培での萎凋病の病原菌であるフザリウム胞子とピシウム菌を殺菌できることを世界で初めて実証した。特に，植物工場では培養液の成分が変質しないことが重要であり，この技術はアルゴンプラズマの照射により，溶液中のH2Oから殺菌力の強いOHラジカルを生成し，殺菌に寄与した後は，即座にOHラジカルが消滅する利点がある。植物工場水耕栽培で大きな課題となっている病原菌の侵入に対して，初めて期待に沿える技術となる。病原菌の侵入は苗の定植時に生じるが，その前後に数分程度のプラズマ照射で防除できることも世界で初めて示した。