Anthracene biodegradation under nitrate-reducing condition and associated microbial community changes

Anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) and degraders in the subsurface environment have aroused increasing attention. Molecular techniques are especially useful when isolates are hard to obtain. Nitrate-reducing microcosms inoculated with aquifer sediment were constructed to investigate anthracene biodegradation. The associated microbial community changes were characterized using terminal restriction fragment length polymorphism analysis (TRFLP) in combination with 16S rRNA gene clone library analysis. A nearly complete removal of anthracene was achieved after an eighty day incubation under the nitrate-reducing condition. The two molecular techniques revealed a significant shift of microbial community structure, coupled with anthracene biodegradation. Species of genera Paracoccus, Herbaspirillum, Azotobacter, and Rhodococcus were grouped into four major operational taxonomic units (OTUs) in the library that was constructed with the microcosm sample on day 80. The enrichment of these genera might have links to anthracene biodegradation under the nitrate-reducing condition. Microbial consortia likely played a part in anthracene degradation.