PRODUCTION Of NUTRIENT SOURCES FOR RHIZOBIUM

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might conclude PUY4 cultured medium showed the same results, but it gave the amount of bacterial
cell at 10 8 cells/ml when compared with G5 medium.
It might cause of the amounts of ethanol in cultured medium. Lie et al., (1991)
Reported that no inhibitory effect of 5 g/l ethanol in a glycerol-yeast extract medium were observed.
However, growth of Bradyrhizobium CB 756 on pure ethanol (0.1, 0.5, 1 and 2.5 g/l) was very poor.
The amounts of ethanol in this experiment was not measured or controlled. But the smells of ethanol
were observed in the 5% sucrose prefermented by yeast. It was suggested that the amount of ethanol
in the medium may effected to the growth of Bradyrhizobium japonicum USDA 110, but not effectd
for Bradyrhizobium spp. THA5 growth.
3.8.2 Cultivation of Bradyrhizobium using medium containing mannitol produced by
yeasts
A total 6000 ml of starch medium (2000 ml of Khao-klong starch medium + 2000 ml
of rice starch medium + 2000 ml of cassava starch medium) were utilized by yeast isolate KAY1. The
cultivation product used for the rhizobial carbon sources was mannitol which produced in the yeast
cells. After centrifugation, the supernatant was discarded. The yeast cells grown from the three starch
cultured medium were pooled into one flask. Cell were lysed by using 4 cycles of freeze-thawing. The
initial high mannitol concentration in cell lysate was adjusted by the addition of distilled water. The
cell lysate medium was adjusted to provide 0.5% (v/v) as same as YMB standard rhizobial culture
medium. The quantitation of mannitol were tested by using High-Performance Liquid
Chromatography (HPLC). And adjusted again as depicted in Table 18.
From the Table 18, The cell lysate medium was adjusted. Other substances: 0.05%
K2HPO4 and 0.01% NaCl were added, and pH adjusted 6.8 at room temperature. After heat
sterilization, the medium was inoculated with B. japonicum USDA 110 and Bradyrhizobium spp.
THA5. The results in Table 19, it clearly showed that the cell lysate medium containing mannitol
could supported the growth of B. japonicum USDA 110 and Bradyrhizobium spp. THA5. The best
results was obtained with 10 8 cells/ml being almost the same as that found with YMB medium.
Mannitol was the traditional carbon and energy source used for small volume cultivation of all