Isolation of bacteria producing bluish-purple pigment and use for dyeing

Janthinobacterium lividum was isolated from wet silk thread whose color bec ame bluish-purple(7,8)). This bacterium produced large amounts of bluish-pu rple pigment on some media containing amino acids, such as Wakimoto medium. The pigment was extracted with methanol and was identified as a mixture of violacein and deoxyviolacein. This pigment could be used to dye not only n atural fibers like silk, cotton and wool, but also synthetic fibers Like ny lon and vinylon, and generally gave a good color tone. The shade depended o n the material. Silk, cotton and wool showed a bluish-purple color, nylon a dark blue color, and acetate a purple color. Dyeing could be performed by a simple procedure consisting of either dipping in the pigment extract or b oiling with the bacterial cells. By changing the dipping time and the tempe rature of the dye bath, shades ranging from light purple to deep bluish-pur ple could be selected. The color fastness of the dyed material was about th e same as that of materials dyed with vegetable dyes, but the color faded e asily when the material was exposed to sunlight. However, since the pigment can be mass-produced by culturing, if these shortcomings could be overcome , the dye may become promising. The pigment displayed an antimicrobial acti vity against phytopathogenic fungi like Rosellinia necatrix which causes wh ite root rot of mulberry(7)). It could also be used as a bio-fungicide.