Characterization of temperature-sensitive and lipopolysaccharide overproducing transposon mutants of Pseudomonas putida CA-3 affected in PHA accumulation
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A library of 20 000 transposon (Tn5) mutants of the gram-negative bacterium Pseudomonas putida CA-3 was generated and screened for adverse affects in polyhydroxyalkanoates (PHA) accumulation. Two mutants of interest were characterized phenotypically. CA-3-126, a mutant disrupted in a stress-related protein Clp protease subunit ClpA, demonstrated greater decreases in PHA accumulation compared with the wild type at reduced and elevated temperatures under PHA-accumulating growth conditions. CA-3-M, which is affected in the aminotransferase class I enzyme, accumulated reduced levels of PHA relative to the wild type and had lower growth yields on all carbon sources tested. Mutant CA-3-M produced up to 10-fold higher levels of lipopolysaccharide relative to the wild type and exhibited 1.2-fold lower aminotransferase activity with phenylalanine as a substrate compared with the wild-type strain. The composition of the lipopolysaccharide produced by the mutant differed from that produced by the... wild-type strain. Growth and PHA accumulation by CA-3-M was the same as the wild type when the nitrogen concentration in the medium was increased to 265 mg N L(-1).
Keywords:polyhydroxyalkanoate / lipopolysaccharide / Pseudomonas putida CA-3
Source:FEMS Microbiology Letters / Federation of European Microbiological Societies, 2009, 292, 2, 297-305
- Wiley-Blackwell Publishing, Inc, Malden
- Higher Education Authority, grant (PRTLI4) in the Centre for Synthesis and Chemical Biology (CSCB) at University College, Dublin.
- J.N.-R. is funded by a research grant from the Environmental Protection Agency Ireland.
- Carbohydrate Research Center is supported in part by the Department of Energy-funded (DE-FG09-93ER-20097) Center for Plant and Microbial Complex Carbohydrates.
- Free full text: https://doi.org/10.1111/j.1574-6968.2009.01504.x