PRODUCTION Of NUTRIENT SOURCES FOR RHIZOBIUM

The results showed that amounts various inoculum sizes, the suitable inoculum sizes
for 2% Khao-klong starch medium was 6%. For 2% rice starch medium, the maximum amounts of
mannitol in cell lysate was gave from 2% inoculum size and 4% inoculum size enhanced the highest
amounts of mannitol in 2% cassava medium starch. From this study, each substrate have the different
in the quantitation of inoculum size and incubation time which gave the maximum yield of the
cultivation products, it could be noticed that amylase enzyme from yeast isolate KAY1 have the
specific to the starch composition of each substrate. The ability of an enzyme to digest raw starch
appears to be associated with its ability to strongly absorb onto the granules (Ueda et al., 1984). The
composition of the nutrient sources in the substrate might be important for the growth of yeasts. From
the Table 6 showed the cassava starch had the highest starch content in major components of the
structure, but it had the organic substances such as protein or fat lower than the other raw materials.
From the results, the maximum yield of mannitol in cell lysate gave at the first and the second day of
cultivation. The Khao-klong starch obtained from polished rice which had so much vitamins and
coenzyme, it might be enhanced the utilization of starch and glucose consumption similar to the high
minerals, and vitamins from yeast extract.
3.7 Sugar alcohol overproduction by physical and chemical stress
To study the effects of sugar alcohol overproduction rate, various conditions heat shock
treatment, salt-stress, and pH regulation by addition of CaCO 3 were investigated.
3.7.1 Sugar alcohol overproduction by the addition of calcium carbonate
The 2% starch medium of either Khao-klong starch, rice starch, or cassava starch was
used as the substrate, and the suitable inoculum sizes: 2%, 4% and 6% used for rice starch, cassava
starch, and Khao-klong starch medium, respectively. Effects of various CaCO 3 concentrations (0%,
0.25%, 0.5%, and 0.75%(w/v)) on the production of reducing sugars and mannitol by yeast isolate
KAY1 when cultured in the medium containing 2% Khao-klong starch were illustrated in Figure 50.
The results showed that when yeast isolate KAY1cultured in 2% Khao-klong starch medium, the
cultivation products was compared. Control which no calcium carbonate added gave the maximum
amounts of mannitol in cell lysate at the first day and the second day of cultivation. The reducing
sugars was maximum amounts at the first day and rapidly decreased in the second day of
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