Table 1.

Industries where biosurfactants are applied: Medicine/pharmaceuticals, petroleum industry, agriculture, cosmetics, and laundry detergents.

Industry	Field	Biosurfactant	Mechanism/Functioning as/Property Used	Reference
Petroleum biotechnology	Extraction of crude oil from reservoirs	Glycolipids and Lipopeptide	Biosurfactants enhance the formation of stable water-oil emulsion, break down oil film in the rock and reduces tension/interfacial tensions thereby reducing the capillary forces that impede oil movement through the rock pores	[38,43]
	Transport of crude by pipelines	Emulsan, alasan, biodispersan	High molecular weight biosurfactants form a stable water-in-oil emulsion which aids oil mobility, viscosity reduction and prevents drop coalescence	[72,199]
	Oil storage tank cleaning	Rhamnolipids	A well-circulated biosurfactant will form an oil-in-water and lift/mobilize oil sludge from the bottom of the tank and solubilize in the already formed emulsion
Bioremediation	Spill remediation (aquatic)	Glycolipid and Trehalose Lipids	Solubilization, oil bioavailable to hydrocarbon-degraders and longer shelf life, biodegradability	[200]
	Soil washing Wastewater treatment	Rhamnolipids Lipopeptides	Reduction of surface and interfacial tensions lead to mobilization and consequent removal of oil from the soil Physically separate, concentrate and remove chemicals of concern for modification, recycling or disposal. Rely on detergency, act as emulsifiers/de-emulsifiers and as a bioavailability enhancer	[134,201]
	Hydrocarbon remediation (soil)	Rhamnolipids, sophorolipids, surfactins	The solubilization property enhances the distribution of contaminants into the aqueous phase, thereby increasing the contaminant bioavailability for biodegradation	[202]
	Heavy metal remediation	Rhamnolipids	Metal-removal mechanisms by biosurfactants from soils are complexation, ion exchange, electrostatic interactions and counterion binding resulting in metal desorption, metal mobilization and metal entrapment by micelles.	[30,203]
Mining Nanotechnology	Precious metal recovery Silver and gold nanoparticles	Biodispersan EPS from algae	Lowers the energy required for cleaving the microstructure of ground limestone. Utilize solubilization property and act as a sequestering agent Biosurfactant producing organisms converts (Ag-Au) NO3 to silver/gold particle using enzyme such as nitrate reductase.	[176,185,193]
Agriculture	Improvement of soil quality	Glycolipid	Consideration of all the soil-related bioremediation	[204]
	Plant pathogen elimination	Rhamnolipids, cyclic lipopeptides	The biosurfactants act on the target cell by disrupting cell surface structures, thereby liberating the intracellular contents of the plant pathogen	[205]
	Plant-microbe interaction	Rhamnolipids	The establishment of the plant-microbe interaction is dependent on the exchange and sensing of a variety of signals (biosurfactants inclusive) by both types of partners.	[158,206]
	Pest control	Lipopeptides by Bacillus subtilis	Detergency property of biosurfactants exhibit toxicity against nematodes and insects	[189]
Medicine/Pharmaceuticals	Gene delivery Antimicrobial activity	MEL Anionic surfactin isoform, rhamnolipids	Cationic liposome bearing MEL-A effectively increased the transfection of genes into mammalian cells The antimicrobial effect of biosurfactants is manifested through detergent-like activities	[15,26,189,207]
	Anticancer activity	Sophorolipids	Biosurfactants as an antiviral agent, halt cell replication in favour of cell differentiation	[10,21]
	Immunological adjuvants	Surfactin,	Immunomodulating biosurfactants stimulate the immune system by increasing the ratio of lymphocyte transformation and migration of polymorph nuclear cells	[22,208]
	Antiviral activity	Sophorolipid diacetate ethyl ester, surfactin	Inactivation of viral lipid envelopes and capsid	[10]
	Anti-adhesive agents	Sophorolipids	Biosurfactants adsorption to a substratum modifies the surface hydrophobicity thereby interfering with microbial adhesion and desorption process	[149]
Bioprocessing	Product recovery	Sophorolipids Rhamnolipids	Biosurfactants form part of the reverse micelle extraction of antibiotics and proteins using their surfactant properties	[17,179,209]
Leather		Biodispersan	Degreasing: used as skin detergent, emulsifier; tanning and dyeing: wetting and penetration, and promoter	[175]
Textile		Trehaosetetraester Unspecified cHAL2	Removal of lipophilic components from fibre surface as a pre-treatment, removal of oil from fibres and enhanced dispersion of dyes for uniform and better penetration into fibre	[175]
Paper	Pulp processing	Biodispersan	Used for washing and deresinification of pulp by defoaming, dispersion and colour levelling	[175]
	Papermaking	Biodispersan	Limestone was effectively grounded using biodispersan and used as a filter in papermaking. Biosurfactant also used in calendaring through wetting, levelling, coating and colouring	[175]
Paint/coating protection		Biodispersan	Employed as a dispersant and as a wetting agent during grinding and stabilization for improved mixing property	[184]
Food industry	Food emulsifier	Polymeric biosurfactants	Modification of the rheological characteristics of the food to a desired consistency and texture using emulsification properties	[210]
	Food stabilizer	Rhamnolipids	Modification of the rheological characteristics of the food to a desired consistency and texture	[210]
Cosmetic industry		Sophorolipids Rhamnolipids MELs	Application of biosurfactants in cosmetics is due to their low irritancy, cytoprotective effect, anti-ageing, acts like an antioxidant, wettability, moisturizing properties, healing and skin toning features	[7,171,211]
Laundry detergents		Sophorolipids MEL	Properties such as foaming, surface tension reduction, solubilization make it suitable for detergent making	[172]