• Applied Biological Chemistry
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• v.36 no.6
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• pp.481-487
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• 1993

The production of sorbose from sorbitol in resting cell system of Acetobacter suboxydans was studied. The conversion of sorbose from sorbitol was markedly influenced by several factors such as the substrate concentration, reaction time, temperature, pH, metal ions, growth factors and aeration in the resting cells. Sorbose production rapidly increased in the range of 6 mg/ml cells with the concentration of 5% sorbitol. For production of sorbose from sorbitol, optimal temperature and pH were $30^{\circ}C$ and 6.0. The production of sorbose from sorbitol was activated by 1 mM of $Al^{+3}$ while inhibited by $Ni^{+2}$. The conversion of sorbitol to sorbose was stimulated by the adding of 1 mM p-aminobenzoic acid and nicotinic acid, respectively. During incubation of 1.5 ml of reaction mixture in 50 ml of Erlenmeyer flask, 5% sorbitol was completly converted to sorbose after 20 hours.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.5
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• pp.340-344
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• 2000

Microbial oxidation of D-sorbitol to L-sorbose by Acetobacter suboxydans is of commercial importance since it is the only biochemical process in vitamin C synthesis. The main bottleneck in the batch oxidation of sorbitol to sorbose is that the process is severely inhibited by sorbitol. Suitable fed-batch fermentation designs can eliminate the inherent substrate inhibition and improve sorbose productivity. Fed-batch sorbose fermentations were conducted by using two nutrient feeding strategies. For fed-batch fermentation with pulse feeding, highly concentrated sorbitor (600g/L) along with other nutrients were fed intermittently in four pulses of 0.5 liter in response to the increased DO signal. The fed-batch fermentation was over in 24h with a sorbose productivity of 13.40g/L/h and a final sorbose concentration of 320.48g/L. On the other hand, in fed-batch fermentation with multiple feeds, two pulse feeds of 0.5 liter nutrient medium containing 600g/L sorbitol was followed by the addition of 1.5 liter nutrient medium containing 600g/L sorbitol at a constant feed rate of 0.36L/h till the full working capacity of the reactor. The fermentation was completed in 24h with an enhanced sorbose productivity of 15.09g/L/h and a sorbose concentration of 332.60g/L. The sorbose concentration and productivity obtained by multiple feeding of nutrients was found to be higher than that obtained by pulse feeding and was therefore a better strategy for fed-batch sorbose fermentation.

• Microbiology and Biotechnology Letters
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• v.8 no.2
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• pp.103-111
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• 1980

This studies were conducted to make vinegar from the physiologcical fallen persinmon during the ripening fruit. The main components of the persimmon mere investigated for the several focal valieties, Some microke acted on the fermentation of persimmon was isolated. The obtained results were as follows : 1) The hardness of fruit was the hithest for Jangjunsi (long persimmon) The hardness of Bansi and Soosi valieties was decreased vary fast after five or six weeks. 2) The total amount of pectin was increased a little in order of Jangjunsi, Bansi and Soosi. The amount of soluble pectin was increased considerably in order of Soosi, Bansi and Jangjunsi. 3) The amount of total sugar and reducing sugar were increased in order of Bansi, Jangjunsi and Soosi. After five or six weeks the amount of reducing sugar of Soosi and Bansi was increased much. The amount of starch was decreased in order of Bansi, Jangjunsi and Soosi, to trace amounts without significent differences. 4) The amount of Soluble tannin was decreased in order of Bansi, Jangjunsi and Soosi. 5) Main microbes on the fermentation of persimmon vinegar were identified as follows: yeast was proved to be Saccharomyces rouxii, CBS 726, and Acetobacters were Gluconobacter oxydans subsp. suboxydans, Gluconobacter oxyaans subsp, osydans, Acetobaeter pasteurians subsp. xylinum 6) During the fermentation, process of persimmon vinegar the amount of reducing sugar and alcohol were decresed, but that of acidity was increased.