Improvement of the "Duckweed-Microbes Co-Cultivation Method" for Stable and Efficient Isolation of Rarely Cultivated Bacteria Using Microfilter Membranes

We recently developed a novel microbial isolation technique, the "duckweed-microbe co-cultivation method", for isolating a wide variety of microbes including rarely cultivated microbes (Microbes Environ. Vol. 33, No. 4, 402-406, 2018). This method involves inoculating aseptic duckweed with environmental microbes and co-cultivating them for a set period. After that, the plants and their surrounding medium are used as microbial isolation sources through the conventional agar plate method. In this project, we aimed to improve this method by using microfilter membranes for pretreating the microbial inoculum. As a result, the use of 1.2 µm pore size microfilter increased isolation efficiency of rarely cultivated microbes representing the phylum Verrucomicrobiota.