[P005] Poster

12:10 PM - 1:00 PM JST(3:10 AM - 4:00 AM UTC)

[P03-407] Development of the Duckweed Holobiont Technology for Future

○Masaaki Morikawa¹ (1. Hokkaido University (Japan))

Keywords:

duckweed,Lemnaceae,holobiont,plant growth-promoting bacteria,biomass

Duckweed is a free-floating plant of the Lemnaceae family. Depending on the growing environment, its total dry biomass can be as much as 40% protein or 30% carbohydrates. As it grows, it removes nitrogen compounds and phosphates, purifying the environmental water and wastewater. These properties make duckweed a promising bioresource for next-generation food, feed, and biofuels. All living organisms form holobiont, an ecological unit, with coexisting microorganisms. Because duckweed has a small body, it is highly susceptible to the influence of a significantly larger number of microorganisms coexisting on the surface¹. For example, duckweed holobionts that coexist with plant growth-promoting bacteria grow twice as fast as natural duckweed². In order to produce duckweed using industrial wastewater that contains low levels of nitrogen compounds, it is very useful to search for indigenous bacteria in the wastewater that promote the duckweed growth³. Moreover, duckweed holobionts that harbor a non-nodule-forming nitrogen-fixing bacterium Azotobacter can grow in nitrogen-free water condition by fixing atmospheric nitrogen⁴. When duckweed is produced outdoors on a large scale, production yields are often significantly reduced due to the proliferation of microalgae that compete with it for nutrient minerals. Duckweed holobionts containing bacteria that inhibit the growth of microalgae can restore its growth when microalgae are coexisted in water⁵. This type of nature-based duckweed holobiont technology may contribute to expand the practical use of the duckweed for future⁶.
¹Ishizawa et al. 2025. Environ. Microbiol. 27, e70181
²Ishizawa et al. 2020. Chemosphere 238, 124682
³Khairina et al. 2021. Chemosphere 268, 129247
⁴Kamal et al. 2023. Plant Growth Regul. 100, 171-180
⁵Pham et al. 2025. Bioresour. Technol. 421, 132110
⁶https://www.nature.com/articles/d42473-023-00334-y