微生物および生化学技術ジャーナル

概要

Bioelectrochemical and Conventional Bioremediation of Environmental Pollutants

John M Pisciotta and James J Dolceamore Jr

Chemical pollutants can adversely affect human and environmental health. In sediments, pollutants such as polycyclic aromatic hydrocarbons (PAHs), heavy metals and pesticides have the potential to exert an array of toxic effects on susceptible organisms. Certain chemicals including dichlorodiphenyltrichloroethane (DDT), various pharmaceuticals and endocrine disrupting agents (ex. nonylphenol) are recalcitrant in sediments, complicating removal. Agents such as dioxins bioaccumulate in plant and animal tissues used for human consumption. Traditional bioremediation employs applied or autochthonous organisms to breakdown or immobilize such environmental contaminants to less hazardous forms. Bacteria, fungi and phototrophs can be used as inexpensive, self-replicating catalysts to metabolize or otherwise neutralize pollutants. Bacteria are particularly useful since metabolically versatile representatives, including various Actinomycetes species, form spores, are resistant to multiple contaminants and survive over a wide range of environmental conditions. Unfortunately, conventional bioremediation suffers from certain drawbacks, like difficulties with subsurface process monitoring. These may be overcome using microbial bioelectrochemical systems (BESs). Recent studies demonstrate that BESs such as sediment Microbial Fuel Cells (sMFCs) can accelerate rates of bioremediation while coupling pollutant metabolism directly to the generation of renewable bio-electricity. BESs can further serve as sensitive pollutant biosensors for remote progress monitoring via existing wireless networks, facilitating bioremediation optimization. Here we review recent progress into conventional and bio-electrochemically mediated bioremediation technologies for common pollutants with a focus on recalcitrant organic pollutants of sediment. Emerging questions, opportunities and drawbacks pertaining to BES microbial technologies are highlighted. Use of BESs to remediate chemically diverse pollutants has proven effective; however, there remains a need to overcome limitations with BES process start up time, scale up and design, remote monitoring and the cost of BES electrodes and catalysts.