Use of Surfactants and Biosurfactants in Oil Recovery Processing and Cellulose Hydrolysis

Review Article

J Bacteriol Mycol. 2019; 6(5): 1114.

Use of Surfactants and Biosurfactants in Oil Recovery Processing and Cellulose Hydrolysis

Abdeli F1, Rigane G2,3, Ben Salem R2, El Arbi M4, Aifa S1 and Cherif S5*

1Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, University of Sfax, Tunisia

2Laboratory of Organic Chemistry LR17ES08 Sciences Faculty of Sfax, University of Sfax, Tunisia

3Department of Chemistry-Physics, Sciences and Technology Faculty, University of Kairouan, Tunisia

4Département de Biotechnologie et Santé, Institue Superieur de Biotechnologie de Sfax, University of Sfax, Tunisia

5Department of Biological Engineering, unité de Biotechnologie des Algues, UR 17 ES 42, University of Sfax, Tunisia

*Corresponding author: Slim Cherif, Department of Biological Engineering, National School of Engineers of Sfax, Unité de Biotechnologie des Algues University of Sfax, UR17ES42, Sfax, Tunisia

Received: October 05, 2019; Accepted: November 04, 2019; Published: November 11, 2019


Surfactants are amphiphilic compounds which can reduce surface and interfacial tensions by accumulating at the interface of immiscible fluids, increasing the solubility, motility, bioavailability and subsequent biodegradation of hydrophobic or insoluble organic compounds. Biosurfactants are surfactants that are produced extracellularly or as a part of the cell membrane by bacteria, yeasts and fungi. Their applications in the environmental industries are promising due to their biodegradability, low toxicity and effectiveness in enhancing the biodegradation and solubilisation of hydrophobic compounds. Examples include rhamnolipids produced by Pseudomonas aeruginosa, sophorolipids produced by Candida bombicola and Bacillus subtilis which produces a lipopeptide called surfactin and other biosurfactant producing microorganisms. The beneficial environmental applications of surfactants and biosurfactants in oil recovery processing is discussed in this review. The recent utilization of these molecules in cellulose hydrolysis is also evaluated.

Keywords: Surfactants; Biosurfactants; Oil Recovery Processing; Cellulose Hydrolysis


Surfactants are a group of surface active molecules. Generally, these molecules reduce the surface tension and interfacial tension in both aqueous solutions and hydrocarbon mixtures. These properties create micro-emulsions in which micelle formation occurs, where hydrocarbons or other hydrophobic substrates can solubilise in water, or water in hydrocarbons. Biourfactants are a group of surfactants produced by microorganisms. The properties of the various biosurfactants have been extensively reviewed [1-5]. Generally, the structure of biosurfactants includes a hydrophilic moiety composed of amino acids or peptides, anions or cations, or mono-, di-, or polysaccharides. The hydrophobic portion is often made up of saturated, unsaturated or hydroxylated fatty acids [5], or composed of amophophilic or hydrophobic peptides. World-wide interest in biosurfactants has increased due to their ability to meet most synthetic surfactants’ requirements [6]. Biosurfactant(s) spontaneous release and function are often related to hydrocarbon uptake; therefore, they are predominantly synthesized by hydrocarbon degrading or tolerating microorganisms. However, some biosurfactants have been reported to be produced on water-soluble compounds, including carbohydrates and alcohols such as glucose, sucrose, glycerol or ethanol [7]. Chemical surfactants have been utilized in the oil industry to aid the clean- up of oil spills and Enhance Oil Recovery from oil reservoirs (EOR). These compounds are not biodegradable and can be toxic to the environment. Biosurfactants have been shown in many cases to have equivalent emulsification properties and are biodegradable. Thus, there is an increasing interest in the possible use of biosurfactants in mobilizing or removing heavy crude oil, transporting petroleum through pipelines, managing oil spills, controlling oil pollution, cleaning oil sludge from oil storage facilities, soil/sand bioremediation and Microbial Enhanced Oil Recovery (MEOR). MEOR offers major advantages over conventional EOR in that lower capital and chemical/energy costs are required and safety towards environment [8]. On the other hand, biourfactant has been one of the most common additives in the bioconversion of lignocellulose to enhance the hydrolytic performance of cellulase enzymes [9]. In this review, a variety of environmental surfactants and biosurfactants applications are discussed. Specific uses of these molecules in oil recovery processing are described. In addition, the application of surfactants and biosurfactants in the hydrolysis of cellulose is also discussed.

Surfactants and Biosurfactants


Surfactants are amphiphilic compounds that reduce the free energy of the system by replacing the bulk molecules of higher energy at an interface. Surfactants have been used industrially as adhesives, flocculating, wetting and foaming agents, deemulsifiers and penetrants [10]. The petroleum industry has traditionally been the major user, as in enhanced oil removal applications. In this application, surfactants increase the solubility of petroleum components [11]. The typical desirable properties are solubility enhancement, surface tension reduction, and low critical micelle concentrations. The effectiveness of a surfactant is determined by its ability to lower the surface tension, which is a measure of the surface free energy per unit area required to bring a molecule from the bulk phase to the surface [12]. The surface tension correlates with the concentration of the surface-active compound until the Critical Micelle Concentration (CMC) is reached. Efficient surfactants have a low critical micelle concentration (i.e. less surfactant is necessary to decrease the surface tension). The CMC is defined as the minimum concentration necessary to initiate micelle formation [13]. In practice, the CMC is also the maximum concentration of surfactant monomers in water phase and it is influenced by pH, temperature and ionic strength. The choice of surfactant is primarily based on product cost [14]. In general, surfactants are used to save energy and consequently energy costs. Charge-type, physicochemical behaviour, solubility and adsorption mode are some of the most important selection criteria for surfactants. New markets are currently being developed for use in the bioremediation of contaminated lands [15]. Surfactants, in addition to organic solvents, chelating agents, acids and bases, have been used to enhance heavy metal removal [16].


Some surfactants, known as biosurfactants, are biologically produced by yeast or bacteria from various substrates including sugars, oils, alkanes and wastes [17]. Biosurfactants are grouped as glycolipids, lipopeptides, phospholipids, fatty acids, neutral lipids, polymeric and particulate compounds [18]. The CMCs of the biosurfactants generally range from 1 to 200 mg/L and their molecular mass is from 300 to 1500 Da [19]. For example the CMC of Staphylococcus sp. 1E biosurfactant is 750 mg/l [8]. They can be potentially effective with some distinct advantages over the highly used synthetic surfactants including high specificity, biodegradability and biocompatibility and safety to human health and environment [1]. For example, glycolipids from Rhodococcus species 413A were 50% less toxic than Tween 80 in naphthalene solubilization tests [20]. A group of biosurfactants that has been studied extensively is the rhamnolipids from improved concentrations of sophorolipid of 150 g/L have been obtained using canola oil and lactose as the substrate [21]. Bacillus subtilis produces a lipopeptide called surfactin (Figure 1) containing seven amino acids bonded to the carboxyl and hydroxyl groups of a 14-carbon acid [22]. Surfactin concentrations as low as 0.005% reduce the surface tension to 27 mN/m, making surfactin one of the most powerful biosurfactants. The primary structure of surfactin was determined many years ago [22]. It is a heptapeptide with a β-hydroxy fatty acid within a lactone ring structure. More recently, the three dimensional structure was determined by 1H NMR techniques [23]. Surfactin folds into a β -sheet structure, which resembles a horse saddle in both aqueous solutions and at the air/ water interface [24].

Citation: Abdeli F, Rigane G, Ben Salem R, El Arbi M, Aifa S and Cherif S. Use of Surfactants and Biosurfactants in Oil Recovery Processing and Cellulose Hydrolysis. J Bacteriol Mycol. 2019; 6(5): 1114.