PRODUCTION Of NUTRIENT SOURCES FOR RHIZOBIUM

Compatible solutes must always behave as osmoregulators, however, and the definition can logically
be extended to include solutes which combine functions (i) and (iii). Potassium chloride (and K + ) has
this role in halophilic bacteria (Aitken and Brown, 1972, quoted in Brown, 1978). Brown (1978)
reported that if a cell was subjected to a water stress by exposing it to a concentrated solution (low a w)
it will either (a) equilibrate thermodynamically with the solution by solution (low a w) it will either
Table 5. Structure and characteristic of sugar alcohols.
Sugar alcohols Structure Description
Glycerol H H H
H - C - C - C - H
OH OH OH
Erythritol
(1,2,3,4-Butanetetrol,
D, L-Erythritol,
Erythrite)
Xylitol
H H
HOH2C – C – C - CH2OH OH H
H OH H
HOH 2C – C - C - C- CH 2OH
OH H OH
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Glycerol is a crytalline substance with a very
low melting point (18°C). It is a constituent
of oils and fats, and is obtained from them by
fermentation. In that sense, glycerol is
naturally occurring.
This four-carbon polyol occurs in lichens,
algae and grasses. Its melting point is 121.5°
C, and it is very soluble in water.
Xylitol is a five-carbon sugar alcohol found
in fruits and vegetables, but the concentration
is usually less than 1%. Its parent sugar,
xylose, is a component of hemicellulose in
wood and corn cobs. The crystalline xylitol
melts at 94°C.