Improved Phytoremediation of Organic Contaminants Through Engineering of Bacterial Endophytes of Trees
This chapter describes the possibilities of using engineered plant- associated endophytic bacteria to improve phytoremediation of organic contaminants by complementing the metabolic properties of their host plant. Analysis of the endophytic communities isolated from trees grown on groundwater contaminated with benzene, toluene, ethylbenzene, and xylene (BTEX) or trichloroethylene (TCE) revealed the presence of many strains able to degrade BTEX compounds or resist TCE. One would therefore expect that natural communities of endophytic bacteria can significantly contribute to the efficiency of the phytoremediation process. However, especially for the phytoremediation of TCE, in situ evapotranspiration measurements revealed that a significant amount of the contaminant and its metabolites evaporated to the atmosphere, pointing to a far from optimal situation.
An alternative proactive approach to natural enrichment is to inoculate plants with endophytic bacteria that are engineered to optimally metabolize the contaminant of interest, thereby improving the overall phytoremediation process. Examples of successful bioaugmentation to improve the phytoremediation of BTEX and TCE under greenhouse and field conditions are presented, and the possibilities to extend this concept to other contaminants are discussed.
KeywordsHorizontal Gene Transfer Organic Contaminant Endophytic Bacterium Yellow Lupine Endophytic Strain
benzene, toluene, ethylbenzene and xylene
Generally Recognized as Safe
- Bacon CW, Hinton DM (2007) Bacterial endophytes. In: Gnanamanickam S (ed) The endophytic niche, its occupants, and its utility. Novozymes Biologicals, Salem and formerly at University of Madras, Chennai, India, 56 pGoogle Scholar
- Beattie GA (2007) Plant associated bacteria: survey, molecular phylogeny, genomics and recent advances. In: Gnanamanickam S (ed) The endophytic niche, its occupants, and its utility. Novozymes Biologicals, Salem and formerly at University of Madras, Chennai, 56 pGoogle Scholar
- Burken JG, Schnoor JL (1996) Hybrid poplar tree phytoremediation of volatile organic compounds. Abstr Pap Am Chem Soc 212: 106–AGROGoogle Scholar
- Mastretta C, Barac T, Vangronsveld J et al (2006) Endophytic bacteria and their potential application to improve the phytoremediation of contaminated environments. Biotechnol Genet Eng Rev 23:175–207Google Scholar
- Yrjälä K, Mancano G, Fortelius C et al (2010) The incidence of Burkholderia in epiphytic and endophytic bacterial cenoses in hybrid aspen grown on sandy peat. Boreal Environ Res 15: 81–96Google Scholar