Production and potential biotechnological applications of microbial surfactants: An overview

Abstract

Microbial surfactants are amphipathic molecules that consist of hydrophilic and hydrophobic domains, which allow partition of two fluid phases of varying degree of polarity. They are classified into two main groups: bioemulsifier and biosurfactant, depending on their molecular weight. Microbial surfactants occur in various categories according to their chemical nature and producing organisms. These biomolecules are produced by diverse groups of microorganisms including fungi, bacteria, and yeasts. Their production is significantly influenced by substrate type, fermentation technology and microbial strains. Owing to inherent multifunctional properties and assorted synthetic aptitude of the microbes, microbial surfactants are mostly preferred than their chemical counterparts for various industrial and biomedical applications including bioremediation, oil recovery; as supplements in laundry formulations and as emulsion-stabilizers in food and cosmetic industries as well as therapeutic agents in medicine. The present review discusses on production of microbial surfactants as promising and alternative broad-functional biomolecules for various biotechnological applications.

Keywords: %, Percent; Akt, Threonine protein kinase; Bioemulsifiers; Biosurfactants; Biotechnological applications; CMC, Critical micelle concentration; CTAB, Cethyltrimethylammonium bromide; Da, Dalton; E24, Emulsification index; IC50, Half-maximal inhibitory concentration; KDa, Kilodalton; MBC, Minimum bactericidal concentration; MIC, Minimum inhibitory concentration; Microbial surfactants; SACs, Surface active compounds; ST, Surface tension; Surface-active compounds; g/L, Gram per litre; h, Hour; mL, Millilitre; mN/M, Millinewton per metre; mg/L, Milligram per liter; mg/mL, Milligram per milliliter; nm, Nanometre; sec, Second; v/v, volume per volume; µL, Microlitre; µg/mL, Microgram per milliliter; µm, Micrometre; ˚C, Degree Celsius.

Fig. 1

Schematic diagram showing mechanism of action of microbial surfactant in the removal of heavy metals from contaminated site.