Surfactants biosurfactants

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

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

Different mechanisms have therefore clearly emerged and it seems premature to draw general conclusions especially in the application of synthetic and natural surfactants to bioremediation, which is discussed in greater detail in Chapter 14. It is important to note, however, that the production of biosurfactants may not be the only mechanism for facilitating the uptake of substrates with... 

The B. licheniformis JF-2 strain produces a very effective surfactant under conditions typical of oil reservoirs. The partially purified biosurfactant from JF-2 was shown to be the most active microbial surfactant found, and it gave an interfacial tension against decane of 0.016 mN/m. An optimal production of the surfactant was obtained in cultures grown in the presence of 5% NaCl at a temperature of 45° C and pH of 7. TTie major endproducts of fermentation were lactic acid and acetic acid, with smaller amounts of formic acid and acetoin. The growth and biosurfactant formation were also observed in anaerobic cultures supplemented with a suitable electron acceptor, such as NaNO3[1106]. 

Surfactant Solutions New Methods of Investigation, edited by Raoul Zana Nonionic Surfactants Physical Chemistry, edited by Martin J. Schick Microemulsion Systems, edited by Henri L Rosano and Marc Clausse Biosurfactants and Biotechnology, edited by Naim Kosaric, W. L. Cairns, and Neil C. C. Gray... 

Defoaming Theory and Industrial Applications, edited by P. R. Garrett Mixed Surfactant Systems, edited by Keizo Ogino and Masahiko Abe Coagulation and Flocculation Theory and Applications, edited by Bohusiav DobiaD Biosurfactants Production Properties Applications, edited by Naim Kosaric Wettability, edited by John C. Berg... 

At concentrations above their aqueous solubility, the so-called c.m.c., low-molar-mass biosurfactants form micelles in the aqueous phase. Micelles are spherical or lamellar aggregates with a hydrophobic core and a hydrophilic outer surface. They are capable of solubilising nonpolar chemicals in their hydrophobic interior, and can thereby mobilise separate phase (liquid, solid or sorbed) hydrophobic organic compounds. The characteristics for the efficiency of (bio)surfactants are the extent of the reduction of the surface or interfacial tension, the c.m.c. as a measure of the concentration needed to bring about this reduction, and the molar solubilisation ratio MSR, which is the number of moles of a chemical solubilised per mole of surfactant in the form of micelles [96]. 

Biosurfactants are commercially available compounds for the in sim or ex situ treatment of hydrocarbons and non-aqueous-phase hquids (NAPLs) in soil and groundwater. Surfactants are highly surface-active compounds that solubilize and/or mobilize contaminants in the subsurface. 

Biosurfactants are natural, biodegradable surfactants synthesized by certain strains of bacteria,... 

Because biosurfactants are natural, biodegradable products, they are an attractive alternative to synthetic surfactants, particularly for in situ remediation. Biosurfactants are also potentially useful agents for oil spill remediation, where they can be used to disperse pollutants that remain in the water or have washed up on land. 

Biosurfactants are naturally occurring surfactants synthesized by certain strains of bacteria, yeasts, and fungi. See Biosurfactants—General (T0119) in the RIMS library/database for more information on this type of surfactant. 

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-... 

Surfactants are used widely in industry, agriculture and medicine. The materials currently in use are produced primarily by chemical synthesis, or as by-products of industrial processes. For a microbial surfactant to penetrate the market, it must provide a clear advantage over the existing competing materials. The major considerations are (1) safety, i.e., low toxicity and biodegradability (2) cost (3) selectivity and (4) specific surface modifications. Biosurfactants exhibit low toxicity and good biodegradability, properties that are essential if the surfactant is to be released into the environment. 

Mueller-Hurtig, G., Wagner, F., Blazczyk, R. Kosaric, N. (1993). Biosurfactants. Surfactant Science Series, pp. 447-69-... 

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]. 

Surfactants are amphiphilic molecules widely used for different purposes in industrial processes, with a worldwide annual demand of about 10 billion (1,2). The most used surfactants are produced from petrochemical sources (3) however, compounds having surface activity characteristics may be synthetized by a wide variety of microorganisms (4,5). Such compounds, called biosurfactants, when compared with the syn-... 

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