Biosurfactant usually refers to
surfactants 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
Glycolipids are lipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the conne ...
,
lipopeptides
A lipopeptide is a molecule consisting of a lipid connected to a peptide. They are able to self-assemble into different structures. Many bacteria produced these molecules as a part of their metabolism, especially those of the genus ''Bacillus'', ' ...
and lipoproteins, and polymeric surfactants as well as particulate surfactants.
Examples
Common biosurfactants include:
*
Bile salts
Bile acids are steroid acids found predominantly in the bile of mammals and other vertebrates. Diverse bile acids are synthesized in the liver. Bile acids are conjugated with taurine or glycine residues to give anions called bile salts.
Primary b ...
are mixtures of micelle-forming compounds that encapsulate food, enabling absorption through the small intestine.
*
Lecithin, which can be obtained either from soybean or from egg yolk, is a common food ingredient.
*
Rhamnolipids, 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 t ...
'', 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. aerug ...
''.
*
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.
References
{{reflist
External links
Production and Characterization of Biosurfactants Using Bacteria Isolated from Acidic Hot Springs
Surfactants
Bioremediation
Cleaning product components
Environmental terminology