Stimulation and Molecular Characterization of Bacterial Perchlorate Degradation by Plant-Produced Electron Donors

• Published in: Environmental science & technology Vol. 40; no. 1; pp. 310 - 317
• Main Authors: Shrout, Joshua D, Struckhoff, Garrett C, Parkin, Gene F, Schnoor, Jerald L
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-01-2006
• Subjects: Anaerobiosis; Applied sciences; Bacteria; Bacteria - metabolism; Biodegradation; Biodegradation, Environmental; Biological and medical sciences; Biotechnology; Carbon - metabolism; Decontamination. Miscellaneous; Earth sciences; Earth, ocean, space; Electrons; Engineering and environment geology. Geothermics; Environment and pollution; Environmental science; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Groundwaters; Industrial applications and implications. Economical aspects; Miscellaneous; Natural water pollution; Perchlorates - metabolism; Plant Roots - chemistry; Plant Roots - metabolism; Pollution; Pollution, environment geology; Populus; Soil and sediments pollution; Soil contamination; Soil Microbiology; Soil Pollutants - analysis; Soil Pollutants - metabolism; Texas; Time Factors; Trees; Water pollution; Water Supply; Water treatment and pollution; United States; North America; Texas; America; Karnack Texas; United States > US; USA, Texas; USA, California, Imperial; Microbial activity; Hybrid variety; Exudate; In situ; Populus nigra; Biostimulation; Chlorates; Perchlorates; Soil pollution; Salicaceae; Phytoremediation; Populus deltoides; Rhizosphere; Decontamination; Dicotyledones; Biotransformation; Ammunition; Angiospermae; Spermatophyta; Water pollution; Bioremediation; Armament; Ground water
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es051130g

Root homogenate from poplar trees (Populus deltoides × nigra DN34, Imperial Carolina) stimulated perchlorate degradation in microcosms of soil and water samples collected at a perchlorate contaminated site, the Longhorn Army Ammunition Plant (LHAAP), located outside Karnack, Texas. Direct use of root products by perchlorate-degrading bacteria was shown for the first time as six pure-culture bacteria isolated from LHAAP perchlorate-degrading microcosms degraded perchlorate when given root products as the sole exogenous source of carbon and electron donor. Nonenriched environmental consortia were able to utilize root products for perchlorate degradation, regardless of prior exposure to perchlorate. Microcosms that contained perchlorate-contaminated groundwater (MW-3) or uncontaminated surface water (Harrison Bayou) as inoculum degraded approximately 240 and 160 mg L-1 perchlorate, respectively, using root products (approximately 440 mg L-1 as COD) over 38 days. The predominant bacterial species in these aqueous microcosms, identified by DGGE, depended only upon the source inoculum as similar sequences were obtained whether root products or lactate was the electron donor. Sequences from DGGE bands that matched species within Dechloromonas, a genus consisting of many perchlorate degraders, were identified in all perchlorate-degrading microcosms. This study demonstrates the ability of root products to drive perchlorate respiration by bacteria and the potential for successful achievement of perchlorate rhizodegradation using in situ phytoremediation.