Characterization of the mutant recombinant strain pseudomonas putida IPM-36 exhibiting anticipating growth on a medium containing an inducer of the cry3A gene expression

Induction of the expression of the delta -endotoxin gene from Bacillus thur ingiensis var. tenebrionis in the recombinant strain Pseudomonas putida IPM -36 negatively affected the viability and the growth rate of the culture. I n order to optimize the insecticide production by the recombinant strain, m utant clones exhibiting anticipating growth on an inducer-containing medium were selected and studied. These clones differed in such aspects as the lo calization of mutations (either in plasmid pBTN11, carrying the cry3A gene, or in the chromosome), growth rate, or the level of delta -endotoxin synth esis after induction. Several obtained mutants proved much superior to P. p utida IPM-36 in their structural and segregation stability, although they w ere as efficient as the original strain with respect to the production of t he insecticide protein Cry3A.