Editor: Alexander Steinbüchel
Characterization of melanin-overproducing transposon mutants of Pseudomonas putida F6
Article first published online: 9 JUL 2009
© 2009 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Microbiology Letters
Volume 298, Issue 2, pages 174–183, September 2009
How to Cite
Nikodinovic-Runic, J., Martin, L. B., Babu, R., Blau, W. and O'Connor, K. E. (2009), Characterization of melanin-overproducing transposon mutants of Pseudomonas putida F6. FEMS Microbiology Letters, 298: 174–183. doi: 10.1111/j.1574-6968.2009.01716.x
- Issue published online: 17 AUG 2009
- Article first published online: 9 JUL 2009
- Received 5 March 2009; accepted 28 June 2009.Final version published online 17 July 2009.
- Pseudomonas putida F6
Two melanin-overproducing Pseudomonas putida F6 mutants were generated using transposon (Tn5) mutagenesis. Mutants were disrupted in a transcriptional regulator (TR) and a homogentisate 1,2-dioxygenase (HDO) gene. Colonies of mutant F6-TR overproduced a black pigment on solid medium. The same mutant (F6-TR) had a 3.7-fold higher tyrosinase activity compared with the wild-type strain when induced with ferulic acid. However in tyrosine uptake assays whole cells of the mutant strain F6-TR consumed eight times less tyrosine compared with the wild-type strain. Mutant F6-HDO produced a diffusible red pigment into the growth medium. Pigment production by mutant F6-HDO is sixfold higher than the wild-type strain. The biomass yield of mutant F6-HDO grown on tyrosine as the sole source of carbon and energy was 1.2-fold lower than the wild-type strain. While the growth of the wild-type strain was completely inhibited by 5 min of exposure to UV light (254 nm) both mutant strains showed survival rates >30%. Mutant F6-HDO was able to tolerate higher concentrations of hydrogen peroxide (H2O2) exhibiting 1.5 times smaller zones of inhibition at 10 mM H2O2 compared with mutant F6-TR and the wild-type strain. The pigments produced by all strains were purified and confirmed to be melanins.