Use of immobilized bacteria for environmental bioremediation: A review

Bioremediation is traditionally carried out using 'free' bacterial cells; however, in recent years, utilization of 'immobilized' bacterial cells has gained attention as a promising technique due to multifarious benefits. This review collates a vast amount of existing literature on the myriad contaminants treated using immobilized bacteria. We also discuss various mechanistic aspects of using immobilized cells for environmental remediation applications, with special attention on cells encapsulated in hydrogels and their implementation in detoxifying harmful contaminants and environmental cleanup. We examine different methods/techniques for immobilizing viable bacterial cells in various supporting matrices, use of single- and multi-species bacterial communities, various growth substrates, and factors affecting the remediation process including mass transfer, kinetic processes and bioreactor configurations used in pilot and field-scale applications. The advantages and limitations associated with the use of immobilized bacteria in a bioreactor for contaminated water treatment are also discussed. From a sustainable futures perspective, resource recovery and retrieval of value-added products along with bioremediation could be an added benefit of the immobilized cell-based treatment system, making it a more cost-effective and viable treatment strategy as well as one that is amenable to the principles of circular economy.

Automated summary

Bioremediation using immobilized bacterial cells has gained attention for its multifarious benefits, ability to treat myriad contaminants, and potential for resource recovery. Various factors, such as growth substrates and kinetic processes, need to be considered when using immobilized cells for environmental remediation. The advantages and limitations of using immobilized bacteria in a bioreactor for contaminated water treatment have been discussed, highlighting its cost-effectiveness and compatibility with circular economy principles.