• KSBB Journal
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• v.26 no.1
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• pp.57-61
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• 2011

The principal objective of this study was to determine the optimal conditions for the production of biosurfactant by the indigenous bacterium, Pseudoalteromonas sp. HK-3, originating from oil-spilled areas. The relationship between total biosurfactant production and the factors affecting biosurfactant production were evaluated by statistical analysis using SPSS software. The effects of various supplemental carbon sources (e.g., glucose, dextrose, mannitol, citrate, acetate) on the maximal production of biosurfactant by the test culture of Pseudoalteromonas sp. HK-3 was then evaluated. As a result, mannitol was found in this study to be the best supplemental carbon source for the production of biosurfactant. A spot inoculation of crude cultural liquid containing the HK-3 cells generated the largest clear zone, whereas only small clear zones appeared around the spots inoculated with either supernatant only or cell pellets following centrifugation. Our results demonstrated that the HK-3 test culture supplemented with 2% mannitol at an initial pH of 6 generated the maximal amount of biosurfactant within 72 h of incubation.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.92-98
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• 1994

The bacteria which secrete surface-active agent and decrease the surface tension of culture broth were isolated from soil samples. Among them, biosurfactant producing strain KK-7 was selected and emulsification was also detected. The KK-7 produced biosurfactant not only lipid but also glucose by using carbon source. Taxonomical characterization tests have demostrated the strain KK-7 to be Pseudomonas aeruginosa. The media composition of the P. aeruginosa KK-7 for the biosurfactant production was 1% glucose, 0.5% tryptone, 0.2% yeast extract, 0.15% potas sium phosphate mono-dibasic, 0.05% MgSO$_{4}$, initial pH 8.5, at 30$\circ $C for 2 days. In this condition, the concentration of biosurfactant was reached CMC 5 in the culture broth. Surface active material was produced maximum at stationary8 phase, but emulsification power was higher at log phase than stationary phase. It was considered that P. aeruginosa KK-7 produced biosurfactant more than one type having defferent properties and each maximum production time was different. The minimun surface tension of biosurfactant in 50 mM Tris buffer (pH8.0) was 28 dyn/cm, and CMC was 1 g/L.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.389-393
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• 2002

Among the bacterial strains isolated from chungkook-jang, Bacillus subtilis CH-1, Bacills circulans K-1 and Bacillus subtitis (natto) N-1, Bacillus subtitis CH-1 showed the highest productivity of biosufactant. A-medium was selected for the basal medium in the large scale production of biosurfactant, and modified to synthetic medium which containing 2% glucose, 0.3% soy peptone, and mineral salts. The surface tension was reduced to maximal value after 96 hr after fermentation, about the 43% of initial tension. Temperature and initial pH of medium was not critical factor for the biosurfactant production. The yield of crude biosurfactant was 6 g/L under the optimum condition.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.171-176
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• 2003

Productivity of biosurfactant (rhamnolipid) by Pseudomonas aeuginosa F722 was investigated in the several culture conditions and culture composition. Biosurfactant production by P. aeuginosa F722 was amounted to 0.78 g/l as the result of the nitrogen sources and carbon sources without investing of optimum conditions. As for that one was investigated, biosurfactant production by P. aeruginosa F722 was amounted to 1.66 g/l. Biosurfactant production increased twofold because the composition of a modified C-medium was investigated efficiently. $NE_4$Cl or $NaNO_2$ inorganic nitrogens and yeast extract or trypton organic nitrogens were effective, but others inorganic nitrogens and organic nitrogens tested were not efficient far biosurfactant production by P. aeruginosa F722. The optimum concentration of $NH_4$Cl; inorganic nitrogen and yeast extract; organic nitrogen were 0.05% and 0.1%, respectively. In various carbon sources, others with the exception of hydrophobic property substrate (n-alkane) and hydrophilic property substrate (glucose, glycol) were not found to be effective fur biosurfactant production, and 3.0% was better in yield than other concentration of glucose. This yielded C-to-N ratios between 17 and 20. In our experiment, the highest biosurfactant production by P. aeruginosa F722 were observed in 5 days cultivation, containing glucose 3.0%, $NH_4$Cl 0.05%, and yeast extract 0.1% and C-to-N ratio was 20. Optimal pH and temperature for biosurfactant production were 7.0 and $35^{\circ}C$, respectively. Under the optimal culture conditions with glucose, biosurfactant production was amounted to 1.66 g/l. Velocity of biosurfactant production and strain growth increased after nitrogen depletion. The average surface tension of 30 mN/m after the 3 days of incubation under optimal culture condition was measured by ring tensionmeter.

• KSBB Journal
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• v.13 no.5
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• pp.511-517
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• 1998

Temperature and pH conditions were studied for an effective biosurfactant production by Pseudomonas aeruginosa YPJ-80. Efficient methods of biosurfactant separation were also investigated. pH-uncontrolled experiments at 35$^{\circ}C$ and an initial pH of 8 resulted in the best cell growth (3.6 g/L) and biosurfactant production (0.073 g biosurfactant/g cell). Biosurfactant separation was most efficient using solvent extraction with chloroform/methanol (2:1 vol%) followed by acidification using 1N HCl.

• Journal of Microbiology and Biotechnology
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• v.21 no.8
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• pp.858-860
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• 2011

Production of biosurfactant can be substantially increased by the addition of precursors like vegetable oils, petroleum products, and other water-insoluble substances. Pseudomonas Ptm+ strain produces biosurfactant in the presence of hexachlorocyclohexane (HCH), which specifically emulsifies HCH, a recalcitrant organochlorine pesticide. Addition of previously produced crude biosurfactant by the same organism as a precursor instead of HCH increased production of biosurfactants with a decrease in the total fermentation time from 32 to 24 h. The main objective of this paper was to find alternatives for HCH as an inducer.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1238-1249
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• 2023

In this study, we sought to investigate the production and optimization of biosurfactants by soil fungi isolated from petroleum oil-contaminated soil in Saudi Arabia. Forty-four fungal isolates were isolated from ten petroleum oil-contaminated soil samples. All isolates were identified using the internal transcribed spacer (ITS) region, and biosurfactant screening showed that thirty-nine of the isolates were positive. Aspergillus niger SA1 was the highest biosurfactant producer, demonstrating surface tension, drop collapsing, oil displacement, and an emulsification index (E₂₄) of 35.8 mN/m, 0.55 cm, 6.7 cm, and 70%, respectively. This isolate was therefore selected for biosurfactant optimization using the Fit Group model. The biosurfactant yield was increased 1.22 times higher than in the nonoptimized medium (8.02 g/l) under conditions of pH 6, temperature 35℃, waste frying oil (5.5 g), agitation rate of 200 rpm, and an incubation period of 7 days. Model significance and fitness analysis had an RMSE score of 0.852 and a p-value of 0.0016. The biosurfactant activities were surface tension (35.8 mN/m), drop collapsing (0.7 cm), oil displacement (4.5 cm), and E₂₄ (65.0%). The time course of biosurfactant production was a growth-associated phase. The main outputs of the mathematical model for biomass yield were Yx/s (1.18), and µ_max (0.0306) for biosurfactant yield was Y_p/s (1.87) and Y_p/x (2.51); for waste frying oil consumption the So was 55 g/l, and Ke was 2.56. To verify the model's accuracy, percentage errors between biomass and biosurfactant yields were determined by experimental work and calculated using model equations. The average error of biomass yield was 2.68%, and the average error percentage of biosurfactant yield was 3.39%.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_1
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• pp.41-45
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• 2001

Pseudomonas aeruginosa EMS1, isolated from activated sludge, was able to grow an produce a biosurfactant on 4.5 % soybean oil, used as the source of energy and carbon. Pseudomonas aeruginosa EMS1 was cultivated at 3$0^{\circ}C$ in a reciprocal shaking incubator, and the highest biosurfactant production was observed after 3 days. Furthermore, Pseudomonas aeruginosa EMS1 was also able to use whey as a co-substrate for biosurfactant production and growth

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.2
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• pp.252-258
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• 1998

The strain producing biosurfactant was isolated from soil smples. The isolated strain was identified as the genus Nocardia through its morphological, cultural and physiolgical characteristics. A high concentration of the biosurfactant by Nocardia sp. L-417 was obtained after 4 days of cultivation in the culture medium containing 3% n-hexadecane, 0.1% $NaNO_3$, 0.02% $K_2HOP_4$, 0.01% $H_2PO_4$, 0.01% $MgSO_4$.$7H_2O$, 0.01% $CaCl_2$, 0.02% yeast extract, and 0.02% tryptone. The optimum pH and temperature for biosurfactant production were pH 6.0 and $30^{\circ}C$, respectively. Furthermore, most biosurfactans were produced during the exponential growth phase, and this fact indicated that the biosurfactans production was growth-associated. The biosurfactant showed the good emulsification activities on various emulsifying substrates such as bunker A, paraffin, corn oil which are used widely in industries.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.313-319
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• 2007

The nutritional medium requirement for biosurfactant production by Bacillus licheniformis K51 was optimized. The important medium components, identified by the initial screening method of Plackett-Burman, were $H_3PO_4,\;CaCl_2,H_3BO_3$, and Na-EDTA. Box-Behnken response surface methodology was applied to further optimize biosurfactant production. The optimal concentrations for higher production of biosurfactants were (g/l): glucose, $1.1;NaNO_3,\;4.4;MgSO_4{\cdot}7H_2O,\;0.8;KCl,\;0.4;CaCl_2,\;0.27;H_3PO_4,\;1.0ml/l;\;and\;trace elements\;(mg/l):H_3BO_3,\;0.25;CuSO_4,\;0.6;MnSO_4,\;2.2;Na_{2}MoO_4,\;0.5;ZnSO_4,\;6.0;FeSO_4,\;8.0;CoCL_2,\;1.0;$ and Na-EDTA, 30.0. Using this statistical optimization method, the relative biosurfactant yield as critical micelle dilution (CMD) was increased from $10{\times}\;to\;105{\times}$, which is ten times higher than the non-optimized rich medium.