Abstract
Selection in continuous culture of Klebsiella pneumoniae mutants that have gained the ability to utilize xylitol while also retaining regulatory control over ribitol utilization was achieved with a dual-substrate regime. Initial steady-state cultures of wild-type organisms were maintained with 0.005% (0.329 mM) ribitol. Mutants of various types proliferated when the composition of the limiting medium was changed to 0.005% ribitol plus 0.250% (16.43 mM) xylitol.