Isolation and characterization of a <Emphasis Type="Italic">Bacillus</Emphasis> species capable of producing tetrodotoxin from the puffer fish <Emphasis Type="Italic">Fugu obscurus</Emphasis>

We obtained puffer fish Fugu obscurus from Wudi, China and analyzed the level of tetrodotoxin (TTX) toxictiy by mouse bioassay. The ovary showed the highest potency (125 MU/g), followed by the liver, intestine, and skin. A TTX-producing strain, namely, W-3, was isolated from the ovary of puffer fish F. obscurus. After culturing at 28 °C for 48 h, toxins were extracted from the liquid medium and analyzed by mouse bioassay, high-performance liquid chromatography, and gas chromatography-mass spectrometry. The results showed that strain W-3 produced TTX and related compounds. Physiological and biochemical characterization and 16S rRNA analysis indicated that this strain represents a novel species within the Bacillus genus; we named this strain as Bacillus sp. W-3. Our results suggested that marine bacteria play a role in the production of TTX in puffer fish F. obscurus.