Application of immobilized microbial cells in biological treatment of contaminated effluent with aromatic compounds: a review article

Background and Objective: Bioremediation of contaminants by living microorganisms is a favorable method for elimination or degradation of pollutants to less harmful substances. In the recent decades, cell immobilization technique has been applied to improve biodegradation efficiency and also overcome to free cells disadvantages. The purpose of this review article is to investigate the application of cell immobilization technology with emphsize on polymeric matrices in the aromatic pollutants removal in laboratory scale (shake flask and bioreactor). Also, the performance of free and immobilized cells has been compared in various environmental conditions. Materials and Methods: In this survey 401, 78, 49, 1450, 0 and 0 relevant articles were found on Scopus, Web of Science, PubMed, Google scholar, SID and Magiran databases, respectively by using keywords such as “Cell immobilization”, “Biodegradation” and “Aromatic. Out of 1978 articles, 1167 articles were excluded from the study. Finally, 811 articles were further reviewed. Results: According to the previous studies, removal of contaminants by immobilized cells using appropriate matrices is higher than freely suspended cell systems. Also, among the cell immobilization systems, cell entrapment in the polymeric carriers is the most widely used method for the bioremediation of aromatic contaminants. Conclusion: Regarding the superiority of immobilized cells in comparison with free cells specially in harsh environments, the reuse of immobilized cells and their application in bioreactors as well as their scale up potential, development and application of these methods can be considered by researchers for wastewater treatment in our country.