Characterization of temperature-sensitive and lipopolysaccharide overproducing transposon mutants of Pseudomonas putida CA-3 affected in PHA accumulation |
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Authors: | Miriam Goff Jasmina Nikodinovic-Runic & Kevin E O'Connor |
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Institution: | Centre for Synthesis and Chemical Biology, Conway Institute for Biomolecular and Biomedical Research, University College Dublin, National University of Ireland, Belfield, Dublin, Ireland |
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Abstract: | 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. |
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Keywords: | polyhydroxyalkanoate lipopolysaccharide Pseudomonas putida CA-3 |
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