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Effects of yeast suspension density on the accumulation ratio of transported solutes
Author(s) -
Kotyk A.
Publication year - 1987
Publication title -
yeast
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.923
H-Index - 102
eISSN - 1097-0061
pISSN - 0749-503X
DOI - 10.1002/yea.320030407
Subject(s) - yeast , carbon dioxide , suspension (topology) , biology , membrane , intracellular , biophysics , biochemistry , suspension culture , oxygen , amino acid , range (aeronautics) , chromatography , chemistry , cell culture , organic chemistry , materials science , ecology , genetics , composite material , mathematics , homotopy , pure mathematics
The previously described effect of cell suspension density on metabolic and transport phenomena in yeast, apparently caused by inhibition by dissolved carbon dioxide, is also observed with the accumulation ratio of both sugars and amino acids where not only a kinetic but also an energetic factor comes into play. Unlike all previously measured metabolic and transport parameters, the dependence of the accumulation ratio on suspension density is not monotonic but shows a pronounced maximum in the range of 4–8 mg dry wt/ml, depending on yeast species and on cultivation conditions. In Rhodotorula gracilis and in Lodderomyces elongisporus it is not due to CO 2 but is semiquantitatively related to the proton‐motive force across the plasma membrane as well as to the intracellular ATP content. It is observed both in oxygen and in argon, over a wide range of pH values and of temperatures, but it is suppressed by metabolic inhibitors. It is expressed only in a range of transported solute concentrations between about 0·1 and 10 m M .