Biosurfactant usually refers to
surfactant
Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, fo ...
s of microbial origin.
Most of the biosurfactants produced by microbes are synthesized extracellularly and many microbes are known to produce biosurfactants in large relative quantities.
Some are of commercial interest.
Classification
Biosurfactants are usually categorized by their molecular structure. Like synthetic surfactants, they are composed of a hydrophilic moiety made up of amino acids, peptides, (poly)saccharides, or sugar alcohols and a hydrophobic moiety consisting of fatty acids. Correspondingly, the significant classes of biosurfactants include
glycolipids,
lipopeptides and lipoproteins, and polymeric surfactants as well as particulate surfactants.
Examples
Common biosurfactants include:
*
Bile salts are mixtures of micelle-forming compounds that encapsulate food, enabling absorption through the small intestine.
*
Lecithin
Lecithin (, from the Greek ''lekithos'' "yolk") is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues which are amphiphilic – they attract both water and fatty substances (and so a ...
, which can be obtained either from soybean or from egg yolk, is a common food ingredient.
*
Rhamnolipid
Rhamnolipids are a class of glycolipid produced by ''Pseudomonas aeruginosa'', amongst other organisms, frequently cited as bacterial surfactants. They have a glycosyl head group, in this case a rhamnose moiety, and a 3-(hydroxyalkanoyloxy)alkanoi ...
s, which can be produced by some species of ''
Pseudomonas
''Pseudomonas'' is a genus of Gram-negative, Gammaproteobacteria, belonging to the family Pseudomonadaceae and containing 191 described species. The members of the genus demonstrate a great deal of metabolic diversity and consequently are able ...
'', e.g., ''
Pseudomonas aeruginosa
''Pseudomonas aeruginosa'' is a common encapsulated, gram-negative, aerobic– facultatively anaerobic, rod-shaped bacterium that can cause disease in plants and animals, including humans. A species of considerable medical importance, ''P. aer ...
''.
*
Sophorolipids are produced by various nonpathogenic yeasts.
* Emulsan produced by ''Acinetobacter calcoaceticus''.
Microbial biosurfactants are obtained by including immiscible liquids in the growth medium.
[
]
Applications
Potential applications include herbicides and pesticides formulations, detergents, healthcare and cosmetics, pulp and paper, coal, textiles, ceramic processing and food industries, uranium ore-processing, and mechanical dewatering of peat.[
]
Oil spill remediation
Biosurfactants enhance the emulsification of hydrocarbons, thus they have the potential to solubilise hydrocarbon contaminants and increase their availability for microbial degradation.enhanced oil recovery
Enhanced oil recovery (abbreviated EOR), also called tertiary recovery, is the extraction of crude oil from an oil field that cannot be extracted otherwise. EOR can extract 30% to 60% or more of a reservoir's oil, compared to 20% to 40% using ...
and may be considered for other potential applications in environmental protection.
References
{{reflist
External links
Production and Characterization of Biosurfactants Using Bacteria Isolated from Acidic Hot Springs
Surfactants
Bioremediation
Cleaning product components
Environmental terminology