Microorganisms Involved in Bioremediation

Bioremediation microbes are grouped by whether they need oxygen. Aerobic microbes break down pollutants — mainly pesticides and hydrocarbons — in the presence of oxygen (Fig. 9.6); a well-known example is Pseudomonas putida, a genetically engineered microorganism (GEM) patented by Ananda Mohan Chakrabarty, which is a multi-plasmid, hydrocarbon-degrading bacterium used to digest hydrocarbons from oil spills. Nitrosomonas europaea can aerobically degrade benzene and a variety of halogenated organic compounds, including trichloroethylene and vinyl chloride, while Ideonella sakaiensis is currently being explored for recycling PET plastics (Fig. 9.7): it uses the enzymes PETase and MHETase to break PET down into terephthalic acid and ethylene glycol, which it can then take up and metabolise as a carbon and energy source. Anaerobic microbes break down pollutants in the absence of oxygen: Dechloromonas aromatica can degrade benzene anaerobically and also oxidise toluene and xylene; Phanerochaete chrysosporium, an anaerobic fungus, shows strong potential for bioremediation of pesticides, polyaromatic hydrocarbons, dyes, trinitrotoluene, cyanides and carbon tetrachloride; Dehalococcoides species are responsible for anaerobic bioremediation of the toxic solvent trichloroethene into non-toxic …