Development of an Amendment Recipe and Identification of Benzene Degraders for Anaerobic Benzene Bioremediation

Abstract

This study aims to develop an optimal recipe of amendment (nutrients and electron acceptors) for anaerobic benzene bioremediation and identify the dominant indigenous benzene-degrading microorganisms in soil and groundwater collected from a fuel service station. Lessons learned in developing and optimizing the amendment recipe follow: (1) salinity and a high initial concentration of benzene were detrimental for benzene biodegradation, (2) a large dose of amendment can shorten the lag time for benzene biodegradation, (3) toluene was an essential co-substance for promoting benzene biodegradation. Stable isotope probing was used to identify microorganism incorporation of 13C from 13C– benzene. Under the experimental conditions, incorporation of 13C can be considered direct evidence of the occurrence of benzene biodegradation. Quantitative polymerase chain reaction showed the primary mechanism for benzene removal to be nitrate reduction. Microbial analyses (denaturing gradient gel electrophoresis and 16S ribosomal RNA) demonstrated that members of genus Dokdonella spp., Pusillimonas spp., and Advenella spp. were predominant in the microbial community and involved in anaerobic benzene bioremediation.