Trends in the Bioremediation of Pharmaceuticals and Other Organic Contaminants Using Native or Genetically Modified Microbial Strains: A Review

Nowadays, numerous synthetic and semisynthetic chemicals are extensively produced and consequently used worldwide for many different purposes, such as pharmaceuticals, pesticides, hydrocarbons with aromatic rings (known as polycyclic aromatic hydrocarbons, PAHs), multi-substituted biphenyls with halogens (such as polychlorinated biphenyls, PCBs), and many other toxic and persistent chemical species. The presence of the aforementioned xenobiotic substances not only in various environmental matrices (water, air, and soil), but also in biological tissues (organisms) as well as in several compartments of raw or processed food (of fruit, vegetal, and animal origin), has raised global scientific concerns regarding their potential toxicity towards non target organisms including humans. Additionally, the ability of those persistent organic pollutants to be magnified via food consumption (food chain) has become a crucial threat to human health. Microbial degradation is considered an important route influencing the fate of those toxicants in each matrix. The technique of bioremediation, either with microorganisms (native or genetically modified) which are applied directly (in a reactor or in situ), or with cell extracts or purified enzymes preparations, is reported as a low cost and potential detoxification technology for the removal of toxic chemicals. The sources and toxic impacts of target groups of chemicals are briefly presented in the present study, whereas the bioremediation applications for the removal of pharmaceuticals and other organic contaminants using microbial strains are critically reviewed. All the recently published data concerning the genes encoding the relevant enzymes that catalyze the degradation reactions, the mechanisms of reactions and parameters that influence the bioremediation process are discussed. Finally, research needs and future trends in the direction of decontamination are high-lightened.