Adaptation of Pseudomonas fluorescens to Low Levels of Water Activity Produced by Different Solutes

摘要

A culture of Pseudomonas fluorescens which grew at a minimal aw of 0.97 in a glucose-salts broth adjusted to that level with NaCl, KCl, or glucose, and at aw 0.9725 with Na2SO4, was adapted to grow at lower aw levels produced by these solutes. Adaptation to growth at a low aw produced by means of one solute did not necessarily result in growth at that aw when another solute was employed to lower the aw. The culture adapted to grow at aw 0.9650 produced by addition of glucose could grow equally well in broth adjusted to that aw with NaCl or KCl, but not Na2SO4. NaCl and KCl permitted growth at the lowest aw level (0.9625), and the culture adapted in KCl did equally well in NaCl.