• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.230-238
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• 2003

Biosurfactant-producing bacteria, showing strong crude oil degrading activity, were isolated from the caverns of National Oil Storage Basement. From the results of biochemical and molecular biological tests, the isolate was identified as Pseudomonas fluorescens PD101. It grows well on liquid media at temperature range from $20^{\circ}C\;to\;37^{\circ}C,$ but it does not produce biosurfactant when grown at $37^{\circ}C$ or at higher temperature. The biosurfactant was stable at broad pH range from 5 to 11 and under heat treatment condition of $100^{\circ}C$ for 30 min. The biosurfactant produced dark blue halo around the colony when grown on SW agar plates, which could confirm the biosurfactant as one of rhamnolipid group. The 700 bp of PCR product could be amplified from DNA of P. flurorescens PD101 by using PCR primers designed from rh1A gene of P. aeruginosa, and it showed $99\%$ of sequence homology with rh1A gene of P. aeruginosa encoding rhamnosyltransferase 1.

• 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.20 no.12
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• pp.1664-1671
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• 2010

A new biosurfactant producer was isolated from palm-oil-contaminated soil and later identified through morphology and DNA sequencing as the yeast-like fungus Exophiala dermatitidis. Biosurfactant production was catalyzed by vegetable oil, supplemented with a basal medium. The culture conditions that provided the biosurfactant with the highest surface activity were found to be 5% palm oil with 0.08% $NH_4NO_3$, at a pH of 5.3, with shaking at 200 rpm, and a temperature of $30^{\circ}C$ for a 14-day period of incubation. The biosurfactant was purified, in accordance with surfactant properties, by solvent fractionation using silica gel column chromatography. The chemical structure of the strongest surface-active compound was elucidated through the use of NMR and mass spectroscopy, and noted to be monoolein, which then went on to demonstrate antiproliferative activity against cervical cancer (HeLa) and leukemia (U937) cell lines in a dose-dependent manner. Interestingly, no cytotoxicity was observed with normal cells even when high concentrations were used. Cell and DNA morphological changes, in both cancer cell lines, were observed to be cell shrinkage, membrane blebbling, and DNA fragmentation.

• Journal of Applied Biological Chemistry
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• v.58 no.1
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• pp.81-88
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• 2015

To characterize the culture medium for the biosurfactant production by Bacillus pumilus IJ-1, the influences of various carbon, nitrogen and mineral sources were assessed. As a result, the highest biosurfactant production was observed after 96 h cultivation containing 0.5% (w/v) tryptone. The strain was able to grow and produce biosurfactant at 0-10% (w/v) NaCl, in the pH range of 5-10, and at $20-45^{\circ}C$. Optimal culture conditions for the biosurfactant production were at $20^{\circ}C$ and pH 9.0 after 72 h incubation and the surface tension of biosurfactant was 27.0 dyne/cm.

• KSBB Journal
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• v.14 no.2
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• pp.192-197
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• 1999

marine bacterium Pseudomonas sp. CHCS-2 produced the biosurfactant in the culture broth which contained 2%(w/v) arabian light crude oil and the productivity of biosurfactant was increased with the addition of glucose. The crude oil in the culture broth was degraded by this strain and carbon chain of $_nC_{12}~_nC_{22}$ was completely degradaded during the incubation for 196 h. The crude biosurfactant was purified by Amberlite XAD-7, Sepharose CL-4B and DEAE-Sepharose CL-6B column chromatography. Therefore, 0.21g/L of the purified biosurfactnat was obtained. The purified biosurfactant was a type of lipoprotein and the molecular weight was estimated as 67kDa by SDS-PAGE. The lipid composition was identified as octadecanoic acid by gas chromatography/mass spectrometry. And then, the N-terminal amino acid sequence of the protein was determined as Ser-Val-lle-Asn-Thr-lle-X-Met-lle-Gly-Gln-Gln- and the sequence did not show homology to any other known lipoprotein. Therefore, the purified lopoprotein was predicted novel biosurfactant.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.346-351
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• 2010

The purpose of this work was to investigate the characteristics of a biosurfactant-producing bacterium isolated from crude-oil contaminated soils. During the incubation of strain HK-3 with 1% crude-oil, bacterial growth pattern, the amount of biosurfactant production, and pH changes were monitored. In order to examine the effect of supplemented carbons on the production of biosurfactant, cultivation of HK-3 cells in BH media with different carbons (e.g. glucose, dextrose, mannitol, citrate, or acetate) revealed that the production of biosurfactant reached the maximal level at the 72 h incubation with mannitol, which the area of clear zone was measured to approximately 7.64 $cm^2$. Identification test using the BIOLOG system, morphology study based on scanning electron microscopy and the 16S rRNA sequence-based phylogenetic analysis assigned strain HK-3 to a Pseudoalteromonas species, designated as Pseudoalteromonas sp. HK-3 which was registered in GenBank as [FJ477041].

• Journal of Life Science
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• v.22 no.2
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• pp.239-244
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• 2012

The purpose of this paper is to analyze the characteristics and chemical components of biosurfactant produced by Pseudomonas sp. G314. Pseudomonas sp. G314 was isolated from soil samples which were contaminated with oil in Daejon area. As such, it produced quality biosurfactant [23]. One type of biosurfactant was kept in a refrigerator, whereas another type of biosurfactant was kept in room temperature. The surface tension activities were then compared. As a result, the biosurfactant from Pseudomonas sp. G314 that was kept at room temperature was stable for 10 days, showing 26.2 dyne/cm of surface tension activity. This result was found to be similar to that of the refrigerator storage. The surface tension of batch culture was 25 dyne/cm, but the culture in the 5 l fermentor was 27 dyne/cm. Therefore, it can be suggested that the large-scale culture is feasible via the fermentor. Biosurfactant from Pseudomonas sp. G314 was estimated to be a kind of glycolipid because it dissolved in acetone and methanol much better than in benzene and toluene [23]. A spot was detected through the elution of silica gel column and the spread of TLC, and the Rf value was 0.58. This spot has a positive reaction with Bail's reagent and rhodamine 6G. Hence, we can conclude that biosurfactant from Pseudomons sp. G314 was a glycolipid containing carbohydrate and lipid.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.170-175
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• 2004

In this paper we studied about Bacillus sp. TBM40-3 producing biosurfactants. The strains were isolated from Taeback Mountain soil and identified as Bacillus sp. by l6S rDNA nucleotides sequence analysis. The TBM40-3 was gram-positive and rod-shaped as observed by field emission scanning microscopy. After the cultivation TBM40-3 in LB broth for 90 h and the surface tension of supernatant was decreased to 29 mN/m. Emulsification activity and stability of crude biosurfactant was measured by using water-immiscible hydrocarbons and oil as substrate. Maximum emulsification activity and stability was obtained from soybean oil. Also, we confirmed that the TBM40-3 producing biosurfactant had an effect on crude oil while showing a superior effect as compared to chemically synthesized surfactants (SDS, Span85, Tween40, Triton X-100). As a result, the Bacillus sp. TBM40-3 producing biosurfactant had potent properties as an emulsifying agent and an emulsion stabilizing agent.

• Journal of Microbiology and Biotechnology
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• v.7 no.3
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• pp.180-188
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• 1997

Bacillus subtilis C9 was selected by measuring the oil film-collapsing activity and produced biosurfactant in a medium containing glucose as a sole carbon source. The biosurfactant emulsified hydrocarbons, vegetable oils and crude oil, and lowered the surface tension of culture broth to 28 dyne/cm. A biosurfactant, C9-BS produced by B. subtilis C9 was purified by ultrafiltration, extraction with chloroform and methanol, adsorption chromatography, and preparative reversed phase HPLC. Structural analyses, IR spectroscopy, FAB mass spectroscopy, amino acid composition, and NMR analyses, demonstrated that C9-BS was a lipopeptide comprising a fatty acid tail and peptide moiety. The lipophilic part consisting of $C_{14}\;or\;C_{15}$ hydroxy fatty acid was linked to the hydrophilic peptide part, which contained seven amino acids (Glu-Leu-Leu-Val-Asp-Leu-Leu) with a lactone linkage.

• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1229-1243
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• 2013

In this paper, an air isolate (NITT6L) has been screened based on hemolytic activity, emulsification activity, drop collapsing test, and oil displacement test, as well as lipase activity. It was found that strain NITT6L was able to reduce the surface tension of the medium from 61.5 to 39.83 mN/m and could form stable emulsions with tested vegetable oils. Morphological, biochemical, 16S rRNA sequencing analyses, and fatty acid methyl ester analysis using gas chromatography confirmed that the air isolate under study was Pseudomonas aeruginosa. Characterization of the biosurfactant using agar double diffusion assay revealed that the biosurfactant was anionic in nature, and CTAB-methylene blue assay and Molisch test revealed its glycolipid nature. The FT-IR spectrum confirmed that the crude biosurfactant was a rhamnolipid. Using unoptimized medium containing sucrose as the carbon source, the isolate was found to produce 0.3 mg/ml of rhamnolipid in batch cultivation (shake flask) at $37^{\circ}C$ and pH 7. Optimization of the medium components was carried out using design of experiments and the yield of rhamnolipid has been enhanced to 4.6 mg/ml in 72 h of fermentation.