| Budget Amount *help |
¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 1988: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1987: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1986: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Research Abstract |
A new immobilized cell system providing protection against toxic solvents such as 2-octanol and toluene was investigated so that normal fermentations could be carried out in a medium containing toxic solvents. The system consists of immobilized growing cells in Ca-alginate gel beads to which vegetable oils such as caster, soy bean, olive and tung oils, which are inexpensive absorbents of solvents, had been added. The system's protective function against a toxic solvent was related to the distribution coefficient of the solvent between a vegetable oil and water. The intensity of the function was larger as the coefficient of the solvent was larger, namely, the equilibrium concentration of the solvent in water was lower.
The new immobilized cell system, also, could provide excellent protection against oil-soluble antimicrobial substances as well as toxic solvents. A new pure culture method without heat-sterilization and air-filtration processes using the new immobilized cell system was investigated. The ethanol fermentation of Saccharomyces cerevisiae and the lactic acid fermentation of Streptococcus lactis were used as model fermentations to develop the new pure culture method. With the new immobilized growing cell systems using caster oil, continuous cultures for both fermentations without heat-sterilization and air-filtration processes were carried out in presence of oil-soluble antimicrobial substances. p-Hydroxy benzoate butyl (POBB), one of food preservatives, and Preventol GD, one of phenol disinfectants, were used as oil-soluble antimicrobial substances. In the case of POBB, continuous cultures for both fermentations could be normally carried out without infection for about 60 h, and in the case of Priventol GD, the continuous culture for ethanol fermentation could be similarly carried out for more than 140 h.
Therefore, a new pure culture method without heat-sterilization and airfiltration processes was developed.
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