• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.55-58
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• 2005

Sophorolipid was produced by Candida bombicola ATCC 22214 from soybean dark oil, a byproduct of soybean oil processing. With a fed-batch culture of C. bombicola for 7 days, 90 g/l of sophorolipid was obtained. The CMC (critical micelle concentration) and minimum surface tension of the sophorolipid in aqueous solution were found to be 150 mg/l and 48 mN/m, respectively. The dispersion capability of sophorolipid was higher than that of the chemical surfactants such as SDS and Brij30. The molar solubility ratio (MSR) of 4-methylnaphthalene was 0.2. Linoleic and oleic acids were the main constituents of the fatty acid composition of the sophorolipid. The sophorolipid showed antimicrobial activity against Propionibacterium acne and Bacillus subtilis.

• KSBB Journal
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• v.24 no.1
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• pp.17-24
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• 2009

For the biosurfactant production process at first Candida bombicola, Sphingomonas yanoikuyae, Sphingomonas chungbukensis and Myxococcus flavescens were studied. As the most productive microorganisms C. bombicola, S. yanoikuyae and S. chungbukensis were selected. During many petrochemical industrial processes variable volatile organic componds are produced and they can cause an unpleasent and unhealthy atmosphere. Usually the volatile organic compounds are treated with chemical detergents. The chemical detergents cannot be easily degradable and can be accumulated in the nature. In this study we tried to develop a production process for the biosurfactants, which can substitute some chemical detergents in some chemical processes, with microorganisms. At second the treatment of the volatile organic compounds with the biosurfactants were tested and compared with the treatment with chemical detergent. The production productivities of the biosurfactant with microorganisms were compared. The growth patterns and kinetics of the microbial cells and the surface tension values of the biosurfactants were studied. The changes of the surface tension in variable pH conditions and sodium chloride concentrations were also studied. The volatile organic carbons were treated in a small plant scale. As the result of this study, it indicated that the specific growth rate of S. chungbukensis was the fastest by 0.144 ($hr^{-1}$). For surface tension, C. bombicola (38.1 dyne/cm) had the lowest value, and solubility of the volatile organic carbon was similar in C. bombicola and S. chungbukensis. (Toluene: about 0.1 Unit, Chloroform: about 0.6${\sim}$0.7 Unit, Benzene: about 0.5${\sim}$0.8 Unit). The biosurfactant, which were produced by C. bombicola, was selected for the further study for the volatile organic carbon treatment. With the biosurfactans from C. bombicola could remove the volatile organic carbon about 80% and this removal rate can be comparable with chemical detergent.

• KSBB Journal
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• v.24 no.2
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• pp.140-148
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• 2009

The microbial biosurfactants can be substituted to the chemical detergents in some industrial processes. In this study we developed a biotechnological processes for the biosurfactants with microorganisms. The biosurfactants have a lot of advantages in comparision with the chemical surfactants. They are proenvironmental even during and after industrial use. But there are not so many kinds of biosurfactants. The production cost and the end price is much higher than the chemical surfactants. But nowdays there are many kinds of microorganisms, which can produce the surfactants in large quantity and fast. We tried to develop a production process for the large scale with some microorganisms. At first Candida bombicola KCTC 7145, Sphingomonas chungbukensis KCTC 2955 and Sphingomonas yanoikuyae KCTC 2818 are cultivated and studied. For the large scale production process we used molasses as a complex medium and tried to optimize the process. Molasses contains 17 to 25% of water, 45 to 50% of sugar and 25% of carbohydrate, it can be fully used as a substrate. The microorganisms have been cultivated in the diluted media with molasses 2, 5, 8 and 10%, respectively, The optimal conditions for the cultivation and the production process have been studied. For the study the optical density, glucose concentration and the surface tension were measured. Candida bombicola KCTC 7145 and the 5% molasses media was selected as an optimal condition for the production process of a biosurfactant. During cultivation of Candida bombicola KCTC 7145 in the 5% molasses medium kerosene and corn oil were added for promoting the biosurfactants.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.195.4-195
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• 2005

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.294-297
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• 2001

Sophorolipid, a biosurfactant produced from Candida bombicola ATCC 22214. showed antimicrobial activity against Bacillus subtilis. Staphylococcus xylosus, Streptococcus mutans, and Propionibacterium acne at 4, 1, 1, 0.5 ppm as MIC(minimum inhibitory concentration). Also 100ppm of sophorolipid inhibited 50% of cell growth of plant pathogenic fungus. Botrytis cinerea. However, sophorolipid showed no effect on the Escherichia coli, indicating its selective antimicrobial activity depending on the cell wall structure. Treatment of B. subtilis with sophorolipid increased the leakage of intracellular enzyme, malate dehydrogenase, indicating the possible interaction of sophorolipid with cellular membrane. Between lactone-type and acid-type sophorolipid, the former showed higher antimicrobial activity.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.247-249
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• 2000

Antimicrobial activity of sophorolipid produced by Candida bombicola ATCC 22214 was investigated, Minimum inhibitory concentration of sophorolipid to Propionibacterium acne and Bacillus subtilis were 0.5 ppm and 4 ppm, respectively. However no antimicrobial activity to E. coli was detected. Indicating the antimicrobial activity of sophorolipid only toward gram positive bacteria. Antifungal activity of sophorolipid was also detected in the hyphae growth assay for Botrytis cinerea. Malate dehydrogenase, a cytoplasmic enzyme, of B. subtilis was remarkably increased with the sophorolipid treatment, indicating the leakage of membrane by sophorolipid. This result shows the potentials of sophorolipid as mild, non-toxic antimicrobial agent.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.220-223
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• 2000

Sophorolipid, a glycolipid type biosurfactant produced from Candida Bombicola, inhibited the growth of bacteria and fungi. Between two types of sophorolipid, acid and lactone form, the latter had more strong antimicrobial activity. Culturing parameters including oil substrate, initial glucose concentration, aeration, culture mode, affected the ratio of two forms. The fatty acid moety varied depending on the oil having different fatty acid chains. Minimum inhibitory concentration of lactonic sophorolipid toward Propionibacterium acne was below 0.5ppm. This result indicated the potentials of sophorolipid as antimicrobial agent in various area including cosmetics.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.27 no.2
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• pp.57-58
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• 2001

Biosurfactant has antibiological activities. Due to its low toxicity, biosurfactant can be applied to human health care products. Posseing the antibiological activities as well as the surfactant properties implies that biosurfactant can be widely used in the cosmetic industry. In this presentation, applications of biosurfactant have been reviewed including the antimicrobial activities of sophorolipid. Sophorolipid, a biosurfactant produced from Candida bombicola ATCC 22214, showed antimicrobial activity against Bacillus subtilis, Staphylococcus xylosus, Streptococcus mutans, and Propionibacterium acne at 4, 1, 1, 0.5 ppm as MIC (minimum inhibitory concentration). Also 100 ppm of sophorolipid inhibited 50% of cell growth of plant pathogenic fungus, B. cinera. However, sophorolipid showed no effect on the Escherichia coli., indicating its selective antimicrobial activity depending on the cell wall structure. Treatment of B. subtilis with sophorolipid increased the leakage of intracellular enzyme, malate dehydrogenase, indicating the possible interaction of sophorolipid with cellular membrane. Between lactone-type and acid-type sophorolipid, the former showed higher antimicrobial activity.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.303-307
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• 2019

Sophorolipid is a biological surfactant of the glycolipid structure produced by Candida bombicola, which generally exists as a mixture of acidic and lactonic forms. In this study, we investigated physico-chemical properties, antibacterial activities, and cytotoxicity of the sophorolipid containing more than 96% of the lactonic form, produced by the gene regulation of production strains and application of a metabolic engineering technique. The lactonic sophorolipid showed a weak acidity in the range of pH 3.2~4.6 when diluted in water at the concentrations from 1 to 0.001 wt%. The $pK_a$ value of the lactonic sophorolipid was estimated to be around 4.3 from the acid-base titration curve. The critical micelle concentration (CMC) of the lactonic sophorolipid was $10^{-2}wt%$, at which the surface tension of aqueous solution was reduced to 36 mN/m. The lactonic sophorolipid showed the minimum inhibitory concentrations (MIC) of $1{\times}10^{-3}$ and $5{\times}10^{-3}g/mL$ against Propionibacterium acnes and Corynebacterium xerosis, respectively. The MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay showed that cytotoxicity of the lactonic sophorolipid was ten times lower than that of triclosan.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.235-241
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• 2002

Sophorolipid, a biosurfactant produced from Candida bombicola ATCC 22214, showed antimicrobial activity against Bacillus subtilis, Staphylococcus xylosus, Streptococcus mutans, and Propionibacterium acne at 4, 1, 1, 0.5 ppm, respectively. Also, 100 ppm of sophorolipid inhibited $50\%$ of cell growth of plant pathogenic fungus, Botrytis cineria. However, sophorolipid showed no effect on Escherichia coli, indicating that its selective antimicrobial activity depended on the cell wall structure. Treatment of B. subtilis with sophorolipid increased leakage of intracellular enzyme, malate dehydrogenase, indicating a possible interaction of sophorolipid with a cellular membrane. Comparing lactone-type and acid-type sophorolipids, the former showed a higher antimicrobial activity. Supplementing other surfactants showed no significant effects on the antimicrobial activity. Animal study showed that 5 g of sophorolipid per kg body weight by oral administration caused no toxicity, and sophorolipid induced no irritation on the skin. These results show potential use of sophorolipid as an active ingredient in healthcare products.