Fuel and oil spills during the exploration, refining, and distribution of oil and petrochemicals are primarily responsible for the accumulation of organic pollutants in the environment. The reduction in contamination caused by hydrocarbons, heavy metals, oily effluents, and particulate matter generated by industrial activities and the efficient recovery of oil at great depths in an environmentally friendly way pose a challenge, as recovery and cleaning processes require the direct application of surface-active agents, detergents, degreasers, or solvents, often generating other environmental problems due to the toxicity and accumulation of these substances. Thus, the application of natural surface-active agents is an attractive solution. Due to their amphipathic structures, microbial surfactants solubilize oil through the formation of small aggregates (micelles) that disperse in water, with numerous applications in the petroleum industry. Biosurfactants have proven their usefulness in solubilizing oil trapped in rock, which is a prerequisite for enhanced oil recovery (EOR). Biosurfactants are also important biotechnological agents in anti-corrosion processes, preventing incrustations and the formation of biofilms on metallic surfaces, and are used in formulations of emulsifiers/demulsifiers, facilitate the transport of heavy oil through pipelines, and have other innovative applications in the oil industry. The use of natural surfactants can reduce the generation of pollutants from the use of synthetic detergents or chemical solvents without sacrificing economic gains for the oil industry. Therefore, investments in biotechnological processes are essential. It is predicted that, in the not-too-distant future, natural surfactants will become viable from an economic standpoint and dominate the world market. The application of biosurfactants in these settings would lead to industrial growth and environmental sustainability. The main goal of this paper is to provide an overview of diverse applications of biosurfactants on environmental remediation, petroleum biotechnology, and the oil industry through a scientific literature review.

The cleaning of machinery, petroleum storage tanks and equipment leads to the accumulation of petroleum products in the environment. The removal of grease adhered to motors is a specific challenge. Cleaning processes require direct application of surfactants or solvents, which most often generate further environmental problems due to the accumulation of these toxic substances. The majority of available surfactants are synthesized from petroleum derivatives. However, environmental laws have motivated the development of natural surfactants as an alternative to existing products. Biosurfactants can be obtained from microorganisms and plants. Biodegradable detergents can also be obtained through chemical synthesis. This review presents different alternatives for obtaining biodetergents as well as their industrial applications for the removal of heavy oils and the reduction of cleaning and labor costs in industries.

Contamination by oil and its derivatives causes serious damage to the environment, motivating the development of innovative technologies for the removal of these contaminants, such as the use of biosurfactants. In the present study, the biosurfactant from Candida tropicalis UCP0996 produced in the low cost-medium formulated with molasses, residual frying oil, and corn steep liquor, was characterized and its toxicity, formulation, and application in removal and biodegradation of oil were investigated. The surface tension of the medium was reduced to 30.4 mN/m, yielding 4.11 g/L of isolated biosurfactant after 120 h. Tests under extreme environmental conditions indicated the stability of the biosurfactant. Chemical characterization by thin layer chromatography (TLC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹H NMR), and gas chromatography and mass spectroscopy (CG-MS) revealed the glycolipidic nature of the biosurfactant. The isolated biosurfactant showed no toxicity against the microcrustacean Artemia salina, while the properties of the formulated biosurfactant remained stable during 120 days of storage. The biosurfactant removed 66.18% of motor oil adsorbed in marine stones and dispersed 70.95% of oil in seawater. The biosurfactant was also able to increase by 70% the degradation of motor oil by seawater indigenous microorganisms, showing great potential to be applied as a commercial additive in the bioremediation of oil spills.

The exploitation of nature and the increase in manufacturing production are the cause of major environmental concerns, and considerable efforts are needed to resolve such issues. Oil and petroleum derivatives constitute the primary energy sources used in industries. However, the transportation and use of these products have huge environmental impacts. A significant issue with oil-related pollution is that hydrocarbons are highly toxic and have low biodegradability, posing a risk to ecosystems and biodiversity. Thus, there has been growing interest in the use of renewable compounds from natural sources. Biosurfactants are amphipathic microbial biomolecules emerging as sustainable alternatives with beneficial characteristics, including biodegradability and low toxicity. Biosurfactants and biosurfactant-producing microorganisms serve as an ecologically correct bioremediation strategy for ecosystems polluted by hydrocarbons. Moreover, synthetic surfactants can constitute additional recalcitrant contaminants introduced into the environment, leading to undesirable outcomes. The replacement of synthetic surfactants with biosurfactants can help solve such problems. Thus, there has been growing interest in the use of biosurfactants in a broad gamut of industrial sectors. The purpose of this review was to furnish a comprehensive view of biosurfactants, classifications, properties, and applications in the environmental and energy fields. In particular, practical applications of biosurfactants in environmental remediation are discussed, with special focus on bioremediation, removal of heavy metals, phytoremediation, microbial enhanced oil recovery, metal corrosion inhibition, and improvements in agriculture. The review also describes innovating decontamination methods, including nanobioremediation, use of genetically modified microorganisms, enzymatic bioremediation, modeling and prototyping, biotechnology, and process engineering. Research patents and market prospects are also discussed to illustrate trends in environmental and industrial applications of biosurfactants.

Oil spills occur during different operations in the energy sector, such as crude oil transport, tank filling and cleaning, and fueling. Such spills are one of the major causes of the accumulation of oil derivatives in the environment, requiring the remediation of soil and marine environments. The production of a biosurfactant by Starmerella bombicola ATCC 222214 was maximized by investigating the effect of different carbon/nitrogen sources and culture conditions. The mineral medium selected for its production was supplemented with 2.0% potato peel flour, 5.0% waste canola frying oil, and 0.20% urea. The culture conditions were a 200 rpm shaking speed, a fermentation time of 180 h, and a 4.0% inoculum size. The yield of isolated biosurfactant was 7.72 g/L. The emulsification rates of heavy oil and motor oil were 65.55 and 95.00%, respectively, indicating an affinity for complex hydrocarbons. In stability tests performed at different pH values, temperatures, and NaCl concentrations, the surface tension ranged from 27.14 to 31.08 mN/m. The critical micelle concentration was 2.0 g/L, at which the surface tension was 33.26 mN/m. The biosurfactant was composed of 6,6-dimethoxy-octanoic acid and azelaic acid, and it exhibited low toxicity to Brassica oleracea and Solanum lycopersicum. In the kinetic test, the biosurfactant allowed for the removal of 82.30%, 96.65%, and 98.25% of exhaust motor oil from sand, silty soil, and clay soil, while in the static test in packed columns, the removal yields were 66.62%, 63.03%, and 58.45%, respectively. The biosurfactant produced in this study is promising for environmental remediation applications in the energy sector.

In the industries across the petroleum chain and those involved in energy generation, the use of petroderivatives as fuel oils is common. To clean parts, equipment and environments contaminated by hydrocarbons, they use expensive, toxic products, bringing risks to the environment as well as to workers’ health. Thus, the aim of this study was to check the stability of a biodetergent prepared using atoxic substances for large-scale production and industrial energy sector application. The relationship between volume (4 to 10 L) and stirring time (5 to 10 min) of the formulation at 3200 rpm and 80 °C was evaluated. The hydrophilic lipophilic balance (HLB), long-term stability (365 days), toxicity and efficiency of low-sulfur, viscous fuel oil removal from metal pieces and floors were investigated. The interaction among operating conditions was shown to influence the features of the product, which achieved approximately 100% stability after a stirring time of 7 min. The emulsion HBL index varied between 4.3 and 11.0. The biodetergent maintained its physicochemical properties during its 365 days of storage and showed high efficiency, removing 100% of the OCB1 impregnated on the metallic surfaces and floors tested. The formulation showed reliability in scale up when submitted to the study of physicochemical factors in the productive process, and safe application, by reducing risks for workers’ health and environment.