Bacteria with natural chemotaxis towards methanol revealed by chemotaxis fishing technique

Motile bacteria often exhibit chemotaxis toward favorable compounds. However, the diversity of bacteria that are attracted to a given substance is largely unknown. This study aimed to reveal the diversity of bacteria with natural chemotaxis towards methanol. We tried to enrich environmental chemotactic bacteria using a glass capillary that is half-filled with methanol solidified with agarose as a trap (“chemotaxis fishing”). The pilot experiment using methanol-chemotactic <i>Methylobacterium aquaticum</i> strain 22A enriched the cells by 46-fold. The method was then applied to bacterial suspensions from paddy water and plants. Depending on the isolation sources and the methods of motility induction, methylotrophic bacteria were enriched 1.2–330-fold. The fished isolates belong to 32 species in 18 genera, mainly containing <i>Acinetobacter, Methylobacterium</i> and <i>Pseudomonas</i> species. Our chemotaxis fishing unveiled a part of diversity of the bacteria with natural chemotaxis towards methanol. A glass capillary containing methanol was used as a trap to enrich methanol-chemotactic bacteria.