Conversion of mesophilic to psychrophilic bacteria.

The minimum temperature of growth of the mesophilic bacterium Pseudomonas aeruginosa has been significantly lowered from approximately 11 degrees to 0 degrees C. This shift in the minimum temperature of growth was accompanied by a corresponding decrease in the maximum temperature of growth. Transfer of this genetic characteristic by a transducing phage grown on a psychrophile or by ultraviolet mutagenesis was used to accomplish these shifts in range of growth temperature.