Preparation, characterization and application of biosurfactant in various industries: A critical review on progress, challenges and perspectives

Due to the increased use of crude oil and other oil-related products, a large amount of waste is produced and discharged into the environment. These wastes contain toxic heavy metals and petroleum hydrocarbon and lead to further deterioration of the terrestrial and aquatic ecosystems. Their increasing amounts and residual leachates are considered the main obstacle to restoring contaminated environments. Biosurfactants are compounds having high emulsification properties, wetting performance, de-emulsification, detergent formulation, foam formation, and surface activity enhancement to minimize the interfacial tension between liquids, a liquid and a gas or a liquid and a solid. Such features make biosurfactants of high potential applications in diverse industrial set-ups. This field attracts attention from scientists (and policymakers) to develop novel, cost-effective and renewable biosurfactants using molecular engineering and emerging downstream processing. This review comprehensively discusses recent applications of biosurfactants, their preparation, characterization, and potential environmental and other industrial applications. The recent advances in biosurfactants using recombinant DNA technology, mutants and hyper-active microbes were also reviewed. We highlighted the use of sophisticated and highly accurate characterization techniques such as high performance-liquid chromatography (HPLC), nuclear magnetic resonance (NMR), thin-layer chromatography (TLC), and gas chromatography–mass spectrometry (GC–MS). Strategies to enhance the efficiency and biosurfactants productivity at a large scale is also discussed.