Degradative Capacities and Bioaugmentation Potential of an Anaerobic Benzene-degrading Bacterium Strain DN11

• Published in: Environmental science & technology 2007-09, Vol.41 (17), p.6222-6227
• Main Authors: Kasai, Yuki, Kodama, Yumiko, Takahata, Yoh, Hoaki, Toshihiro, Watanabe, Kazuya
• Format: Article
• Language: English
• Subjects: 01 COAL, LIGNITE, AND PEAT; ABANDONED SITES; ANAEROBIC CONDITIONS; Anaerobiosis; Applied sciences; AQUIFERS; Azoarcus; Azoarcus - genetics; Azoarcus - isolation & purification; Azoarcus - metabolism; Bacteria; BASIC BIOLOGICAL SCIENCES; BENCH-SCALE EXPERIMENTS; BENZENE; Benzene - metabolism; Benzene Derivatives - metabolism; BIOCHEMICAL REACTION KINETICS; BIODEGRADATION; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Biotechnology; COAL; COAL GASIFICATION PLANTS; DECONTAMINATION; DISTILLATION; DNA; Earth sciences; Earth, ocean, space; Electrophoresis, Agar Gel; Engineering and environment geology. Geothermics; Environment and pollution; ENVIRONMENTAL SCIENCES; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Genes; GROUND WATER; Groundwater; Groundwaters; Hydrocarbons; Industrial applications and implications. Economical aspects; JAPAN; KINETICS; Natural water pollution; Pollution; Pollution, environment geology; Polymerase Chain Reaction; REMOVAL; Ribonucleic acid; RNA; RNA, Ribosomal, 16S - genetics; Studies; SULFATE-REDUCING BACTERIA; TEMPERATURE DEPENDENCE; TOLUENE; Water Pollutants, Chemical - metabolism; Water treatment and pollution; XYLENES
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es062842p

Azoarcus sp. strain DN11 is a denitrifying bacterium capable of benzene degradation under anaerobic conditions. The present study evaluated strain DN11 for its application to bioaugmentation of benzene-contaminated underground aquifers. Strain DN11 could grow on benzene, toluene, m-xylene, and benzoate as the sole carbon and energy sources under nitrate-reducing conditions, although o- and p-xylenes were transformed in the presence of toluene. Phenol was not utilized under anaerobic conditions. Kinetic analysis of anaerobic benzene degradation estimated its apparent affinity and inhibition constants to be 0.82 and 11 μM, respectively. Benzene-contaminated groundwater taken from a former coal-distillation plant site was anaerobically incubated in laboratory bottles and supplemented with either inorganic nutrients (nitrogen, phosphorus, and nitrate) alone, or the nutrients plus strain DN11, showing that benzene was significantly degraded only when DN11 was introduced. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments, and quantitative PCR revealed that DN11 decreased after benzene was degraded. Following the decrease in DN11 16S rRNA gene fragments corresponding to bacteria related to Owenweeksia hongkongensis and Pelotomaculum isophthalicum, appeared as strong bands, suggesting possible metabolic interactions in anaerobic benzene degradation. Results suggest that DN11 is potentially useful for degrading benzene that contaminates underground aquifers at relatively low concentrations.