Abstract: Purposes: To identify the classification position of a blue pigment producing strain named as B9-8 isolated from low temperature sewage and to characterize pigment produced by it. Methods: Based on morphological observation and 16 S rRNA sequence alignment, the strain was identified as a possible new member of the genus Janthinbacterium. Results: The blue pigment from this strain showed a maximum absorption peak at 579 nm and had good solubility in water and organic solvents. In addition, it was stable to heat and pH but unstable to light. After 3 d of exposure to natural sunlight a loss of 61.3% was found. Low concentrations of metal ions had little effects on its stability, whereas some metal ions at high concentrations, especially Al3+, had a great impact on its stability, resulting in a loss as high as 73.1%. Conclusion: Therefore, we speculated that the blue pigment might be violacein.

Key words: blue pigment, strain identification, properties, stability