• Journal of Korean Society of Water and Wastewater
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• v.18 no.6
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• pp.724-730
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• 2004

Effects of the biosurfactant produced by Rhodococcus erythropolis on the solubilization and biodegradation of phenanthrene were investigated. Based on surface tension measurements, the average critical micelle concentration of the biosurfactant was estimated to be about 16mg TOC/L. The apparent solubility of phenanthrene increased linearly with the addition of biosurfactants above the CMC, and the concentration of solubilized phenanthrene was 38.9mg/L in 322mg TOC/L biosurfactant solution. The weight-solubilization ratio of biosurfactants for phenanthrene was approximately 118.8mg/g, this value was over 5 times greater than that of sodium dodecyl sulfate. Using a known phenanthrene degrader, batch phenanthrene biodegradation experiments were conducted with and without biosurfactants in liquid culture. The rate and extent of phenanthrene mineralization by the phenanthrene degrader with biosurfactants were much greater than those without biosurfactants. The greater phenanthrene mineralization observed in the presence of biosurfactants is attributed to the increased phenanthrene concentration in the aqueous culture due to the partitioning of the compound to biosurfactant micelles. The biosurfactant did not exhibit any toxic effect on mineralization of glucose by the phenanthrene-degrader.

• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.56-61
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• 1999

Pseudomonas sp. SW1 grew and produced biosurfactants on 3% hexadecane as the energy and carbon source. As a result of biosurfactant synthesis, the surface tension of the medium was reduced from 72 dyne/cm to 30 dyne/cm. The properties of biosurfactants that were purified from Pseudomonas sp. SW1 were investigated. The purification procedure included acid precipitation from culture supernatant, silica gel G60 column chromatography, and Sephadex G-150 gel filtration. The biosurfactants were separated into two different types, viz., types I and II. Biosurfactant type Isignificantly reduced the surface tension of water from 72 to 27 dyne/cm at concentration levels above 30 mg/l. The surface tension of water was reduced to a minimum of approximately 30 dyne/cm by biosurfactant type II at concentration levels over 80 mg/l. The biosurfactants were effective in a wide range of pHs, at NaCl concentrations of up to 4%, at $CaCl_2$ concentration up to 100 mM, and at temperatures up to $200^{\circ}C$ for 8 h.

• Journal of the Korean Applied Science and Technology
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• v.13 no.2
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• pp.1-20
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• 1996

Surfactants are the surface-active molecules that display amphiphilicity, Because of this surface activity and amphiphilicity, surfactants have been used in wide industrial applications such as foods, detergents, cosmetics, medicine, polymers, paints, flotation, textiles. These days, their applications extend to high-technology industries such as microelectronics, magnetic recording material, advanced batteries, novel separations, etc. As new applications of surfactants are found and the demand of the surfactants increases, surfactant industry has been more pressed to face a formidable challenge, which is to develop surfactants that are envirionmentally friendly. In this regard biosurfactants may be alternatives to chemical surfactants, since biosurfactants are biologically compatible, more biodegradable, less toxic, and highly specific. Because of these excellent advantages over those of chemical surfactants, much efforts have been made in biosurfactant research. This article reviews biosurfactants in several aspects, that is, their definition, structures, properties, applications, and prospects.

• Research in Plant Disease
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• v.23 no.2
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• pp.177-185
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• 2017

Bacillus amyloliquefaciens LM11 was isolated from the feces of larvae of the rhino beetle and showed strong antifungal activities against various phytopathogenic fungi by producing biosurfactants. In this study, our overall goal was to determine relationship between biosurfactants produced from the LM11 strain and its role in growth inhibition of phytopathogenic fungi. Production and expression levels of B. amyloliquefaciens LM11 biosurfactants were significantly differed depending on growth phases. Transcriptional and biochemical analysis indicated that the biosurfactants of the LM11 strain were greatly enhanced in late log-phase to stationary phase. Inhibitions of phytopathogenic mycelial growth and spore germination were directly correlated (P<0.001, R=0.761) with concentrations of the LM11 cell-free culture filtrates. The minimum inhibitory surface tension of the culture filtrate of the B. amyloliquefaciens LM11 grown in stationary phase to inhibit mycelial growth of the phytopathogenic fungi was 38.5 mN/m (P<0.001, R=0.951-0.977). Our results indicated that the biosurfactants of B. amyloliquefaciens LM11 act as key antifungal metabolites in biocontrol of plant diseases, and measuring surface tension of the cell-free culture fluids can be used as an easy indicator for optimal usage of the biocontrol agents.

• Journal of Life Science
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• v.12 no.6
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• pp.745-751
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• 2002

Several bacterial strains producing biosurfactants were isolated from polluted marine and soil by oil. One of the strains named LSC11 showed strong production activity of biosurfactants. This strain was identified as a Bacillus sp. LSC11 based on the morphological, biochemical, and physiological characteristics. The biosurfactant, produced by the strain, emulsified crude oil, vegetable oil, and hydrocarbons. The surface tension of the culture broth of Bacillus sp. LSC11 decreased to 32 mN/m. The crude biosurfactant was obtained from the culture broth by acid precipitation, freeze drying, solvent extraction, and evaporation. The emulsifying activity of the biosurfactant showed better than the chemically synthesized surfactant (SDS, Span40, Span 85). The biosurfactants had strong properties as an emulsifying agent and as an emulsion-stabilizing agent.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.356-366
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• 2021

Two marine actinobacterial isolates, RG3 and RG8, were identified using 16Sr DNA as Streptomyces althioticus RG3 and Streptomyces californicus RG8 and submitted to the database of genetic information with accession numbers MW661230 and MW661234, respectively; they were found to have emulsification indexes of 60 ± 2.5% and 53 ± 2.2%, respectively. The biosurfactants obtained were stable at a temperature of 35℃ for both strains; they were stable at 10% NaCl, in the case of S. althioticus RG3 and at 10-15% NaCl in the case of Str.californicus RG8; both strains produced the most biosurfactant when exposed to alkaline conditions. We characterized the biosurfactants, including features such as their chemical composition, using Fourier transform infrared spectroscopy analysis. The antimicrobial activity of the biosurfactant extracts was evaluated using the well diffusion method against Vibrio alginolyticus MK170250, Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 4027, and Staphylococcus aureus ATCC 25923. S. althioticus RG3 biosurfactants were found to have better antimicrobial activity than those of Str. californicus RG8, indicating that they may be used in pharmaceutical industries and in the manufacture of antifouling products.

• 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.

• 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.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.645-649
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• 1998

A glycolipid type of biosurfactants was obtained from a strain which had been isolated from soil. The cell was identified as Pseudomonas aeruginosa from taxonomic characteristics and was designated as YPJ80. Thin layer chromatography and deoxyhexose detection tests were done to verify the type of biosurfactant. Critical micelle concentration (CMC) of the surfactant was observed to be 50 ppm and the minimum surface tension was 30.1 mN/m. As an emulsifier, YPJ80 biosurfactant was superior to emulsan in the emulsification of crude Arabian light oil.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.371-376
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• 2002

A biosurfactant-producing bacterial strain was selected from diesel-contaminated soil by measuring the oil-film collapsing activity and identified as Pseudomonas aeruginosa D2D2. When glucose and olive oil were used as carbon sources, 11.46 g/1 of biosurfactant was obtained. Based on TLC analysis, the biosurfactant produced from P. aeruginosa D2D2 was identified as a glycolipid, consisting of two types of biosurfactants (Type I and Type II). The purified glycolipid reduced the surface tension of the culture from 72 dyne/cm to 27 dyne/cm. The hydrophilic and hydrophobic moiety of the biosurfactant were rhamnose and ${\beta}$-hydroxydecanoic acid, as determined by FAB-MS and NMR analyses, respectively.