Biosurfactant-enhanced

Biosurfactant-Enhanced EK Only a few studies using biosurfactants... 

Biosurfactants are useful in contaminant biodegradation because biosurfactants enhance HOC bioavailability by increasing HOC aqueous solubility Ju and Elektorowicz (2000) used rhamnolipids produced by P. aeruginosa to enhance electrokinetic remediation of phenanthrene-contaminated soil. This study showed the potential for on-site production of biosurfactant that was then directly introduced to the electrokinetic cell. Biosurfactants thus show promise as enhancers of biodegradation and for the solubilization and desorption of PAHs in electrokinetic processes. 

Cameotra SS, Bollag J-M (2003). Biosurfactant-enhanced bioremediation of polycyclic aromatic hydrocarbons. Critical Reviews in Environmental Science and Technology 30(2) 111-126. 

Sekelsky AM, Shreve GS (1999) Kinetic model of biosurfactant-enhanced hexadecane biodegradation by Pseudomonas aeruginosa. Biotechnol Bioeng 63 401-409... 

In many cases, environmental contamination caused by industrial activity is due to accidental or deliberate release of organic and/or inorganic compounds into the environment. Such compounds pose problems for remediation, as they become easily bound to soil particles. The application of biosurfactants in the remediation of organic compounds, such as hydrocarbons, aims at increasing their bioavailability (biosurfactant-enhanced... 

Lai, C. C., Huang, Y. C., Wei, Y. H., Chang, J. S. Biosurfactant-enhanced removal of total petroleum hydrocarbons Irom contaminated soil. Journal of Hazardous Materials 2009,167,609-614. 

Zhang Y, RM Miller (1992) Enhanced octadecane dispersion and biodegradation hy a Pseudomonas rhamno-lipid surfactant (biosurfactant). Appl Environ Microbiol 58 3276-3282. 

S. C. Lin, J. C. Goursaud, P. J. Kramer, G. Georgiou, and M. M. Sharma. Production of biosurfactant by Bacillus licheniformis strain JF-2. In E. C. Donaldson, editor. Microbial enhancement of oil recovery recent advances Proceedings of the 1990 International Conference on Microbial Enhancement of Oil Recovery, volume 31 of Developments in Petroleum Science, pages 219-226. Elsevier Science Ltd, 1991. 

The alkane rc-tetradecane was found to have significant effect on desulfurization ability, with the rate being 10 times more than that obtained when using glucose for biocatalyst growth. This effect was associated with production of rhamnolipids by the strain. However, the mechanism by which alkane actually enhances desulfurization activity, whether it is by assisting in biosurfactant production or by some other mechanism was not reported. However, this biocatalyst was found to be active for only a short period (4h) during its desulfurization test with oils. 

Scheibenbogen, K., Zytner, R. G., Lee, H. Trevors, J. T. (1994). Enhanced removal of selected hydrocarbons from soil by Pseudomonas aeruginosa UG2 biosurfactants and some chemical surfactants. Journal of Chemical Technology and Biotechnology, 59, 53—9-... 

Churchill, S. A., Griffin, R. A., Jones, L. P. Churchill, P. F. (1995). Biodegradation rate enhancement of hydrocarbons by an oleophilic fertilizer and a rhamnolipid biosurfactant. Journal of Environmental Quality, 24, 19—28. 

A variety of factors affect the horizontal and vertical migration of PAHs, including contaminant volume and viscosity, temperature, land contour, plant cover, and soil composition (Morgan Watkinson, 1989)- Vertical movement occurs as a multiphase flow that will be controlled by soil chemistry and structure, pore size, and water content. For example, non-reactive small molecules (i.e., not PAHs) penetrate very rapidly through dry soils and migration is faster in clays than in loams due to the increased porosity of the clays. Once intercalated, however, sorbed PAHs are essentially immobilized. Mobility of oily hydrophobic substances can potentially be enhanced by the biosurfactant-production capability of bacteria (Zajic et al., 1974) but clear demonstrations of this effect are rare. This is discussed below in more detail (see Section 5 5). 

Zhang, Y. Miller, R. M. (1992). Enhanced octadecane dispersion and biodegradation by a Pseudomonas rhamnolipid surfactant (biosurfactant). Applied and Environmental Microbiology, 58, 3276-82. 

Micro-foam, or colloidal gas aphrons have also been reportedly used for soil flushing in contaminated-site remediation [494—498], These also have been adapted from processes developed for enhanced oil recovery (see Section 11.2.2.2). A recent review of surfactant-enhanced soil remediation [530] lists various classes of biosurfactants, some of which have been used in enhanced oil recovery, and discusses their performance on removing different type of hydrocarbons, as well as the removal of metal contaminants such as copper and zinc. In the latter area, the application of heavy metal ion complexing surfactants to remediation of landfill and mine leachate, is showing promise [541]. 

Many organisms growing on hydrocarbons are able to produce substances that lower the interfacial tension of the growth medium, and may serve to emulsify oil in water (30, 38-41). Such biosurfactant production is believed to facilitate microbial uptake of hydrocarbon by increasing the substrate surface area via emulsification. Thus, it permits greater contact between hydrocarbon and bacteria and enhances the substrate dissolution rate. Alternatively, biosurfactant production may increase the solubility of the hydrocarbons, which are utilized only in solution. 

Banat, I. M. (1995), Biosurfactants production and possible uses in microbial enhanced oil recovery and oil pollution remediation a review. Bioresource Technology, 51, 1-12. 

The effectiveness of biosurfactants was demonstrated in soil-washing tests using two SOU samples contaminated with PAHs over several decades. Biosurfactants from urban waste compost (cHAL) enhanced PAH desorption from one soil 2-4-fold, relative to SDS. In addition, cHAL showed much less absorption than did SDS (12%-54% vs. 68%-95%). The results indicate that biosurfactants isolated from compost, instead of synthetic surfactants, can be used for soU remediation (Montoneri et af, 2009). 

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