urfactant’ are amphipathic molecules with both hydrophilic
and hydrophobic (generally hydrocarbon) moieties that
partition favourably at the interface between fluid phases with
different grades of polarity and hydrogen bonding such as
oil/water or air / water interfaces. These polarities render
surfactants capable of reducing surface and interfacial tension
and forming micro emulsion where hydrocarbon can be
solubilize in water or where water can solubilize in
hydrocarbons. Such characteristics confer excellent detergency,
emulsifying, forming and dispersing traits. Almost all surfactants
currently in use are chemically derived from petroleum:
however, interest in microbial surfactants has been steadily
increasing in due to their diversity, environmental friendly and
easy production. Biosurfactants are amphiphilic compounds,
structurally diverse group of surface active molecules excreted
extracellularly, synthesized by large varieties of microorganisms,
which vary in their chemical properties and molecular
size. These molecules reduce surface and interfacial tension in
both aqueous solutions and hydrocarbon mixture.
The main functions of bio-surfactant in microbial cells are
emulsification of water insoluble substrates such as hydrocarbons
and facilitate its transport into the cell to stimulate the growth.
Similarly adhesion and desorption of cell is essential for the
survival of microbes in unfavourable conditions like toxin
accumulation, limited nutrients availability.
In this article, have presented the application of biosurfactant,
methods used for its isolation, production and
purification.
II. CLASSIFICATION AND MICROBIAL ORIGIN
Bio-surfactants are categorized mainly by their chemical
composition and their microbial origin. A major class of biosurfactants
includes:
• Glycolipids: most common carbohydrate in
combination with long chain aliphatic acid of
hydroxyl aliphatic acid. The glycolipid can be
categorised as Rhamnolipids(commonly produced by
Pseudomonas aeruginosa), Trehalolipids (commonly
associated with Actinomycetes, Mycobacterium,
Nocardia And Corynebacterium), Sophorolipids
(produced by different strains of Yeast and Torulopis
bombicola and T. petrophilum).