scholarly journals BIOSURFACTANTS SYNTHESIS BY PSEUDOMONAS AERUGINOSA BACTERIA ISOLATED FROM THE SURFACE OF MUSSELS OF THE BLACK SEA

2021 ◽  
pp. 71-83
Author(s):  
M. O. Finogenova ◽  
M. B. Galkin ◽  
A. S. Semenets ◽  
I. V. Prishchenko ◽  
G. S. Kaleva ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Black Sea ◽  
Nutrient Medium ◽  
Reference Strain ◽  
Wave Length ◽  
The Black Sea ◽  
Active Compounds ◽  
Surface Active ◽  
Culture Growth ◽  
Surface Active Compounds

Aim. Establishing of the ability to synthesize surface-active compounds by Pseudomonas aeruginosa bacteria isolated from the surface of Black Sea mussels. Methods. During the research several marine Pseudomonas spp strains isolated from petroleum hydrocarbon contaminated areas of Black Sea wereused: P. aeruginosa M1, P. aeruginosa M4 and P. aeruginosa PA01 as reference strain in suspension and biofilm cultures (LB and Giss media). Cultivation of Pseudomonas aeruginosa strains was performed at 37 °C for 120 and 168 hours. Planktonic culture growth was determined spectrophotometrically on the wave length 600 nm. Biofilm mass was determined spectrophotometrically on the wave length 592 nm by CV-test. The presence of surface-active compounds was determined in a drop test. The quantitative content of rhamnolipids was evaluated by the color reaction of rhamnose with orcin. Results. P. aeruginosa strains M1 and M4 isolated from Black Sea mussel’s surfaces synthesize 25% and 66% more surfactants than the reference strain PA01. All strains in Giss medium synthesized 10–20 times less rhamnolipids than in LB medium. In biofilm cultures the same biosurfactant synthesis dependence on the composition of the nutrient medium is observed as in suspension cultures. According to the intensity of rhamnolipid production in biofilm cultures, the studied strains can be arranged in the following row: P. aeruginosa M4 > P. aeruginosa M1 >> P. aeruginosa PA01.Conclusions. The strains of P. aeruginosa isolated from the Black Sea are more efficient producers of rhamnolipids than the reference strain of P. aeruginosa PA01; the intensity of biosynthesis of surfactants significantly depends on the composition of the nutrient medium and the method of cultivation.

scholarly journals Assessing the Role of Pseudomonas aeruginosa Surface-Active Gene Expression in Hexadecane Biodegradation in Sand

2002 ◽  
Vol 68 (5) ◽  
pp. 2509-2518 ◽  
Author(s):  
P. A. Holden ◽  
M. G. LaMontagne ◽  
A. K. Bruce ◽  
W. G. Miller ◽  
S. E. Lindow
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Porous Media ◽  
Liquid Culture ◽  
Sand Culture ◽  
Water Interface ◽  
Unsaturated Porous Media ◽  
Wild Type ◽  
Active Compounds ◽  
Surface Active ◽  
Surface Active Compounds

ABSTRACT Low pollutant substrate bioavailability limits hydrocarbon biodegradation in soils. Bacterially produced surface-active compounds, such as rhamnolipid biosurfactant and the PA bioemulsifying protein produced by Pseudomonas aeruginosa, can improve bioavailability and biodegradation in liquid culture, but their production and roles in soils are unknown. In this study, we asked if the genes for surface-active compounds are expressed in unsaturated porous media contaminated with hexadecane. Furthermore, if expression does occur, is biodegradation enhanced? To detect expression of genes for surface-active compounds, we fused the gfp reporter gene either to the promoter region of pra, which encodes for the emulsifying PA protein, or to the promoter of the transcriptional activator rhlR. We assessed green fluorescent protein (GFP) production conferred by these gene fusions in P. aeruginosa PG201. GFP was produced in sand culture, indicating that the rhlR and pra genes are both transcribed in unsaturated porous media. Confocal laser scanning microscopy of liquid drops revealed that gfp expression was localized at the hexadecane-water interface. Wild-type PG201 and its mutants that are deficient in either PA protein, rhamnolipid synthesis, or both were studied to determine if the genetic potential to make surface-active compounds confers an advantage to P. aeruginosa biodegrading hexadecane in sand. Hexadecane depletion rates and carbon utilization efficiency in sand culture were the same for wild-type and mutant strains, i.e., whether PG201 was proficient or deficient in surfactant or emulsifier production. Environmental scanning electron microscopy revealed that colonization of sand grains was sparse, with cells in small monolayer clusters instead of multilayered biofilms. Our findings suggest that P. aeruginosa likely produces surface-active compounds in sand culture. However, the ability to produce surface-active compounds did not enhance biodegradation in sand culture because well-distributed cells and well-distributed hexadecane favored direct contact to hexadecane for most cells. In contrast, surface-active compounds enable bacteria in liquid culture to adhere to the hexadecane-water interface when they otherwise would not, and thus production of surface-active compounds is an advantage for hexadecane biodegradation in well-dispersed liquid systems.

The Isolation and Prospect of Biosurfactants

2012 ◽  
Vol 550-553 ◽  
pp. 1124-1127
Author(s):  
Yun Yun Xu ◽  
Tao Zhang ◽  
Xin Nian Li ◽  
Lei Chen ◽  
Hao Wang
Keyword(s):  
Environmental Remediation ◽  
Oil Production ◽  
Active Compounds ◽  
Strong Interest ◽  
Biological Technology ◽  
Natural Surface ◽  
Potential Applications ◽  
Surface Active ◽  
Surface Active Compounds

Biosurfactants are natural surface-active compounds mainly synthesized by microorganisms, which have distinct advantages like no secondly pollution and friendly to environment compared with chemical surfactants. With the development of modern biological technology, biosurfactants have been shown a variety of potential applications, including medicine, agriculture, oil production and environmental remediation, so it has already caused many researchers a strong interest in the production of biosurfactants making use of biological technology. A review is made from the isolation of biosurfactants. In addition, on the foundation of the analysis,several suggestions about the development of biosurfactants are proposed.

scholarly journals Aerosol hygroscopicity at high (99 to 100%) relative humidities

2009 ◽  
Vol 9 (4) ◽  
pp. 15595-15640 ◽  
Author(s):  
C. R. Ruehl ◽  
P. Y. Chuang ◽  
A. Nenes
Keyword(s):  
Surface Tension ◽  
Inorganic Compounds ◽  
Droplet Diameter ◽  
Pure Water ◽  
Sodium Dodecyl ◽  
Bulk Solution ◽  
Active Compounds ◽  
Surface Active ◽  
Surface Active Compounds ◽  
Aerosol Hygroscopicity

Abstract. The hygroscopicity of an aerosol largely determines its influence on climate and, for smaller particles, atmospheric lifetime. While much aerosol hygroscopicity data is available at lower relative humidities (RH) and under cloud formation conditions (RH>100%), relatively little data is available at high RH (99.2 to 99.9%). We measured the size of droplets at high RH that had formed on particles composed of one of seven compounds with dry diameters between 0.1 and 0.5 μm, and calculated the hygroscopicity of these compounds. We use a parameterization of the Kelvin term, in addition to a standard parameterization (κ) of the Raoult term, to express the hygroscopicity of surface-active compounds. For inorganic compounds, hygroscopicity could reliably be predicted using water activity data and assuming a surface tension of pure water. In contrast, most organics exhibited a slight to mild increase in hygroscopicity with droplet diameter. This trend was strongest for sodium dodecyl sulfate (SDS), the most surface-active compound studied. The results suggest that partitioning of surface-active compounds away from the bulk solution, which reduces hygroscopicity, dominates any increases in hygroscopicity due to reduced surface tension. This is opposite to what is typically assumed for soluble surfactants. Furthermore, we saw no evidence that micellization limits SDS activity in micron-sized solution droplets, as observed in macroscopic solutions. These results suggest that while the high-RH hygroscopicity of inorganic compounds can be reliably predicted using readily available data, surface-activity parameters obtained from macroscopic solutions with organic solutes may be inappropriate for calculations of the hygroscopicity of micron-sized droplets.

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