Improvements in the Duckweed-Microbe Co-cultivation Method for the Stable and Efficient Isolation of Rarely Cultivated Bacteria Using Microfilter Membranes.

We recently proposed a novel microbial isolation technique, the "duckweed-microbe co-cultivation method", for isolating a wide variety of microbes, including rarely cultivated microbes. This method involves the inoculation of aseptic duckweed with environmental microbes followed by co-cultivation for a set period. Plants and their surrounding medium are then used as microbial sources for isolation in the conventional agar plate method. In the present study, we improved the method by using microfilter membranes (pore sizes of 0.8-1.2‍ ‍μm) to pretreat microbial inocula, which increased the isolation efficiency of rarely cultivated microbes representing the phylum Verrucomicrobiota.