Biotechnology Techniques

, Volume 8, Issue 5, pp 345-350

First online:

Staining method of poly(3-hydroxyalkanoic acids) producing bacteria by nile blue

  • Shiro KitamuraAffiliated withResearch Institute of Innovative Technology for the Earth (RITE)
  • , Yoshihara DoiAffiliated withPolymer Chemistry Laboratory, The Institute of Physical and Chemical Research (RIKEN)

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Using an ethanol solution of nile blue, we have developed an efficient method to detect the colonies of poly(3-hydroxyalkanoic acids) (PHA) producing bacteria on the agar plate. When the bacterial colonies with PHA granules were stained with nile blue, the stained colonies fluoresced bright orange on the irradiation of UV light. In the fluoresce emission spectra, fluorescence intensity increased with an increase in the PHA content of bacterial cells.Alcaligenes eutrophus andA.latus colonies with poly(3-hydroxybutyric acid) (PHB) homopolymer exhibited an emission maximum at 580nm on the excitation at 490nm. On the other hand,Pseudomonas oleovorans andP.putida with medium-chain-length (mcl-) PHA copolymers of C6, C8 and C10 units exhibited an emission maximum at 570nm.