Biosurfactants applications

Southam et al. [54] studied the effect of biosurfactants on the biodegradation of waste hydrocarbons. To degrade hydrocarbons, bacteria must adsorb onto the surfactant-oil interface of 25-50 nm in thickness. Approximately 1% of all the biosurfactant was needed to emulsify the oil. This type of studying with a transmission electron microscope showed that the microorganisms were able to uptake nanometre-sized oil droplets during growth. More of this type of research is required to determine the mechanism of hydrocarbon metabolism and biosurfactant applications. 

F. Ochoa-Loza, Physico-chemical factors affecting rhamnolipid biosurfactant application for removal of metal contaminants from soil, Ph.D. dissertation. University of Arizona, Tucson, 1998. 

Table 14.1 Major commercial manufacturers of biosurfactants and uses Company Biosurfactants Applications...

Biosurfactants Production Properties Applications, edited by Naim Ko-saric... 

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... 

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... 

In addition to desulfurization activity, several other parameters are important in selecting the right biocatalyst for a commercial BDS application. These include solvent tolerance, substrate specificity, complete conversion to a desulfurized product (as opposed to initial consumption/removal of a sulfur substrate), catalyst stability, biosurfactant production, cell growth rate (for biocatalyst production), impact of final desulfurized oil product on separation, biocatalyst separation from oil phase (for recycle), and finally, ability to regenerate the biocatalyst. Very few studies have addressed these issues and their impact on a process in detail [155,160], even though these seem to be very important from a commercialization point of view. While parameters such as activity in solvent or oil phase and substrate specificity have been studied for biocatalysts, these have not been used as screening criteria for identifying better biocatalysts. 

Finnerty, W. R. Singer, M. E. (1984). A microbial biosurfactant physiology, biochemistry and applications. Developments in Industrial Microbiology, 25, 311-40. 

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]. 

Fiechter, A., Biosurfactants Moving Toward Industrial Application, Trends Biotechnol. 10 208-217 (1992). 

A number of different mechanisms have therefore clearly emerged and it seems premature to draw general conclusions especially with respect to the application of these natural surfactants to bioremediation that is discussed in greater detail in Chapter 8, Section 8.2.1. It is important to note that production of biosurfactants may not be the only mechanism for facilitating the uptake of substrates with low water solubility. For a strain of Rhodococcus sp. that did not produce surfactants, the rates of degradation of pyrene dissolved in water in the presence of insoluble, nondegradable 2,2,4,4,6,8,8-heptameth-ylnonane exceeded those predicted for physicochemical transfer from the solvent to the aqueous phase, but could be accounted for on the basis of uptake both from the interface and from the aqueous solution (Bouchez et al. 1997). 

These substances are used industrially with several objectives, but for many years, they have been synthesized chemically. The biological surface-active compounds, biosurfactants, which began to be used in the last decades, are produced by some bacterial strains that degrade or transform petroleum components [1, 2]. These biosurfactants are getting notoriety because they can be used in several industrial applications, as a result of their biodegradability advantages, production from renewable sources, and functionality under extreme conditions [3]. 

Biosurfactants Production-Properties-Applications, B. DobiaS (Ed.), Surfactant Sci. Ser., Vol. 48, Marcel Dekker, New York, 1993. 

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