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

• Korean Journal of Microbiology
• /
• v.33 no.3
• /
• pp.187-192
• /
• 1997

The strain producing biosurfactant was isolated from soil. The isolated strain was identified as the genus Tsukamurella through its morphological, cultural, physiological, menaquinone type, fatty acid composition characteristics. The highest biosurfactant production by Tsukamurella sp. 26A was observed after 4 days cultivation in the culture medium containing n-hexadecane 7%, $NaNO_{3}$ 0.2%, $K_2HPO_4$ 0.001%, $MgSO_{4}$ center dot $7H_{2}O$ 0.02%, $CaCl_2$ center dot $2H_{2}O$ 0.02%, yeast extract 0.02%(pH 6.8-7.0, 30^{\circ}C.$ The surface and interfacial tension of an aqueous solution reached 30 mNim and 1.5 mNim, respectively. The biosurfactant stabilized oil-in-water emulsion with a variety of hydrocarbons, edible oils and petroleum oils.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.1
• /
• pp.95-104
• /
• 2018

Biosurfactants or microbial surfactants are surface-active biomolecules that are produced by a variety of microorganisms. Biodegradability and low toxicity have led to the intensification of scientific studies on a wide range of industrial applications for biosurfactants in the field of environmental bioremediation as well as the petroleum industry and enhanced oil recovery. However, the major issues in biosurfactant production are high production cost and low yield. Improving the bioindustrial production processes relies on many strategies, such as the use of cheap raw materials, the optimization of medium-culture conditions, and selecting hyperproducing strains. The present work aims to obtain a mutant with higher biosurfactant production through applying mutagenesis on Bacillus subtilis SPB1 using a combination of UV irradiation and nitrous acid treatment. Following mutagenesis and screening on blood agar and subsequent formation of halos, the mutated strains were examined for emulsifying activity of their culture broth. A mutant designated B. subtilis M2 was selected as it produced biosurfactant at twice higher concentration than the parent strain. The potential of this biosurfactant for industrial uses was shown by studying its stability to environmental stresses such as pH and temperature and its applicability in the oil recovery process. It was practically stable at high temperature and at a wide range of pH, and it recovered above 90% of motor oil adsorbed to a sand sample.

• Journal of Applied Biological Chemistry
• /
• v.54 no.1
• /
• pp.7-14
• /
• 2011

Bacillus subtilis JK-1 showed degradation activity against crude oil, gasoline, kerosene, and light oil, and this strain was used as a crude biosurfactant producing microorganism in this study. To optimize the culture medium for production of crude biosurfactant, the influences of various carbon, nitrogen and mineral sources were assessed. The highest biosurfactant production by B. subtilis JK-1 was observed after 96 h cultivation, containing 1.0% (w/v) soluble starch as a carbon source and 0.5% (w/v) skim milk as a nitrogen source, and carbon to nitrogen concentraion (C/N) ratio was 2.0. For the biosurfactant production 0.1% (w/v) of $KNO_3$ was the most effective mineral source. Comparison of biosurfactant production indicates that B. subtilis JK-1 produces more biosurfactant in the optimum medium established in this study than LB and TSB. Under the optimum medium, the surface tension of culture broth of B. subtilis JK-1 was decreased from 47.3 dyne/cm to 24.0 dyne/cm after cultivation of 48 h.

• Korean Journal of Microbiology
• /
• v.46 no.4
• /
• pp.346-351
• /
• 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 Applied Biological Chemistry
• /
• v.54 no.3
• /
• pp.153-158
• /
• 2011

Optimal culture conditions were characterized for production of crude biosurfactant of Bacillus subtilis JK-1. During incubation of B. subtilis JK-1, the bacterial growth pattern, changes of the surface tension at variable temperatures, pH and NaCl concentrations in bacterial culture medium were studied. The strain was able to grow and produce biosurfactant at $15-45^{\circ}C$, in the pH range of 6-10, and at 0-10% (w/v) NaCl. In case, culture broth pH was gradually changed to neutral or weak alkaline. Optimal culture conditions for crude biosurfactant production were at $35^{\circ}C$ and pH 7.0 after 48 h incubation and the surface tension of biosurfactant was 24.0 mN/m. Besides, as the concentration of NaCl was increased from 0 to 10% (w/v), the growth was decreased, pH of the culture broth was converted from weak alkaline to acidic, and the surface tension rised.

• Microbiology and Biotechnology Letters
• /
• v.48 no.1
• /
• pp.48-56
• /
• 2020

This study aimed to optimize the culture conditions to improve the crude biosurfactant activity of Bacillus pumilus IJ-1, using a 3³ full-factorial design of response surface methodology (RSM). It was found that submerged fermentation of B. pumilus improved the activity of the crude biosurfactant. The factors selected for optimization were NaCl concentration, temperature, and tryptone concentration. Response surface analysis revealed that the fitted quadratic model was statistically significant and produced an adequate R² value (0.9898) and a low probability value (<0.0001). The optimum level for each factor was found to be 0.567% (w/v) NaCl, 21.851℃ and 0.765% (w/v) tryptone, respectively. Crude biosurfactant activity was found to be most affected by tryptone concentration; then temperature, and finally NaCl concentration. Our results may potentially facilitate large-scale biosurfactant production from B. pumilus IJ-1.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.497-500
• /
• 2000

A biosurfactant producing bacteria strain, D2D2 was selected from diesel-contaminated soil, and identified as Pseudomonas aeroginosa. A glycolipid produced by P. aeroginosa D2D2 was purified by ethyl acetate extraction and adsorption chromatography. The biosurfactant was Identified as glycolipid which has two types of biosurfactants as a results of TLC analysis. The purified glycolipid biosurfactant reduced the surface tension of water to 27 dyne/cm. In time course studies of growth and rhamnolipid production in a minimal salts medium containing 1.5% glucose and 1.5% olive oil, a maximum rhamnolipid yield of $11.45gL^{-1}$ was obtained after 5 days.

• Microbiology and Biotechnology Letters
• /
• v.24 no.2
• /
• pp.185-190
• /
• 1996

Some microorganisms including yeasts produce surface tension-decreasing biosurfactants. The strain G-1, the best producer of biosurfatants was isolated from the soil and identified as Rhodotorula sp., which was not discribed any report. The Rhodotorula sp. G-1 produced biosurfactant from vegetable oils, but failed to produce it from n-alkane or carbohydrate. Yeast extract was found to be more effective for the biosurfactant production as nitrogen source than any other inorganic nitrogen source. The composion of the optimal medium contained the following conponents: soybean oil 4%, glucose 2%, yeast extract 0.5%, KH$^{2}$PO$^{4}$ 0.1%, K$^{2}$HP0$^{4}$ 0.l%, MgSO$^{4}$ 5%, CaCl$^{2}$ 0.01%, NaCl 0.01%, pH 6.0. The surface tension activity was increased to 14% when, at first, the culture broth was fermented with only soybean oil as carbon sourse, and after 90 hours, feeded glucose, than that Of glucose and soybean oil added to it simultaneously. The maxium yield of the biosurfactant was about 15 g/l by after 90 hours, the feeding method of glucose.

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