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Accumulation of carbohydrate by Escherichia coli B/r/1 during growth at low water activity
Author(s) -
Roller S.D.,
Anagnostopoulos G.D.
Publication year - 1982
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1982.tb05073.x
Subject(s) - sucrose , monosaccharide , carbohydrate , chemostat , arabinose , galactose , chemistry , carbohydrate metabolism , osmoregulation , biochemistry , food science , biology , fermentation , bacteria , xylose , ecology , genetics , salinity
The carbohydrate content of Escherichia coli B/r/1, grown in a glucose or arabinose‐limited salts medium in a chemostat, increased by a factor of 2–4 when the water activity (a w ) of the medium was reduced to 0.986 by addition of NaCl, KCl or sucrose. The biomass decreased by 30–45%. The sucrose system resulted in the lowest biomass and carbohydrate content. The monosaccharide part of the accumulated carbohydrate consisted of glucose or glucose and arabinose in the cultures fed glucose and arabinose, respectively, and accounted for 50% or more of the total carbohydrate in the NaCl and KCl systems and 16.79% in the sucrose system. In addition, the K + content depended on the solute and related inversely to the monosaccharide content, being highest in the sucrose system. The combined molarity of the monosaccharide and K + was deduced to be far in excess of that required for osmotic equilibration of the cultures, especially in the sucrose system. These observations are discussed in the context of osmoregulation, the effects of solutes on glucose metabolism and the morphological changes that occur in cultures at low a w .