Biosurfactants and bioemulsifiers for soil remediation as a green solution from waste

Surfactants are widely used in domestic, industrial, and medical sectors, with a growing global market. However, synthetic surfactants pose environmental concerns, as they often enter ecosystems as recalcitrant organic pollutants due to their molecular properties. Residual surfactants persist in the environment, contributing to pollution. These issues highlight the need for safer, sustainable alternatives. Biosurfactants and bioemulsifiers are surface-active agents that reduce surface and interfacial tensions, derived from biological systems or microorganisms and alternative to synthetic surfactants. They can also facilitate environmental remediation, regenerative agriculture, and industrial applications. Key advantages include low toxicity, high biodegradability, potential derivation from renewable resources and domestic, urban and agricultural waste streams, increasing compatibility with circular economy principles. Therefore, they are fundamental to advancing environmental sustainability and allowing industries to transition towards greener solutions, aligning with global goals for zero-pollution objectives. This review highlights the application of these products in the bioremediation of contaminated soils and in enhanced oil recovery. It also addresses production challenges, particularly those related to cost and scalability, emphasizing the use of waste feedstock from strategic industries as a key factor in sustainability. Furthermore, recent advances and new strategies in metabolic, genetic, enzymatic and process engineering are discussed, which aims to optimize production yields and pave the way for broader commercialization. Available studies on biodegradability and toxicological profiles are reviewed to provide context for real-world applications. To support decision-making by managers and policymakers, real case studies are examined, along with a comparative analysis of the performance of biogenic versus synthetic surfactants in soil remediation. Finally, the review outlines current limitations and priority challenges in remediation practices that must be addressed. In conclusion, the successful commercialization and application of biosurfactants and bioemulsifiers will require a dual focus: advancing technological innovation to reduce production costs and aligning with operational demands, while also strengthening safety assessments to deepen understanding of their environmental and health impacts—ensuring their role as scientifically robust and socially responsible solutions.