Abstract
Growth of Erwinia chrysanthemi in a glucose/yeast extract/salts medium, adjusted to various water activities (a w) with NaCl, was not observed below 0·970 a w. Growth rate increased when a w was lowered from 0·998 to 0·990, below which growth rate again declined rapidly. Similar results were obtained using mannose to adjust a w. Growth rate declined linearly between the limits of 0·998 a w and 0·970 a w on a sodium polypectate/yeast extract/salts medium adjusted with mannose. Extracellular pectate lyase (PL) production on the sodium polypectate/yeast extract/salts medium increased when a w was lowered from 0·998 a w to 0·990 a w using NaCl as a w adjuster. However, when either mannose or lactose was used to adjust a w over this range, PL production decreased considerably. PL was more stable in the presence of NaCl than with lactose or mannose. The significance of the differential effects of NaCl as opposed to organic a w adjusters on PL production is discussed.
Published Version
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