COMPETITIVE INTERACTIONS IN MIXED CULTURES OF ISOGENIC STRAINS OF PSEUDOMONAS-PUTIDA BS394 CONTAINING 4 DIFFERENT NATURAL PLASMIDS OF CAPROLACTAM UTILIZATION

Four studied natural plasmids of caprolactam utilization (pBS262, pBS2 65, pBS268, and pBS276) transferred into strain Pseudomonas putida BS3 94 imparted the capacity of growth on caprolactam characterized by dif fering physiological parameters, namely lag period duration, maximal g rowth rate, and efficiency of substrate utilization in batch culture. The strain carrying the pBS265 plasmid predominated in mixed continuou s cultures with different degrees of limitation, including conditions of non-limited growth. Strains with increased biomass yield or maximal cell division rate had no selective advantage in mixed continuous cul tures. A strain which appeared to have an increased rate of substrate utilization had a selective advantage.