PRODUCTION Of NUTRIENT SOURCES FOR RHIZOBIUM

Table 5. (continued).
Sugar alcohols Structure Description
Mannitol
( D -mannitol,
Mammite)
H H OH OH
HOH 2C- C- C- C- C-CH 2OH
OH OH H H
Source : Shallenberger (1993); Christain (1994); Voet (1995).
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The sugar alcohol, mannitol, is naturally
occuring and is found in exudates of olive
and plane trees, and in seaweed. It may be
prepared by the reduction of mannose. The
crystals melt at 166-168°C. The L-form is
known, but does not occur in nature.
(a) equilibrate thermodynamically with the solution by losing water and perhaps by admitting some of
the extracellular solute(s), in which case it had died or become dormant, or (b) suffered a temporary
loss of water but used energy to accumulated a solute(s) to a concentration thermodynamically
commensurated with the extracellular a w. The solute can be a metabolite which was retained or an
extracellular substance which was accumulated. The effect of solution accumulation was to lower
intracellular a w values to the extended that water again entered the cell to achieved thermodynamic
parity with the outside. Thermodynamic parity normally included a factor for an appropriated level of
turgor pressure.
1.4 Physiology of xerotolerant microorganisms
The term “osmophilic” was introduced in 1912 (Brown, 1978). It has been useful but it is
misleading, firstly because of the connotations which osmotic pressure can have, and secondly
because its suffix, “-philic”, implies a requirement for, rather than a tolerance of, a concentrated
growth medium (Brown, 1976, quoted in Brown, 1978). Sugar- and salt-tolerance can be used in