SGER: Molecular probing and identification of active RDX-utilizing microorganisms

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CBET- 0834973Chu, Kung-HuiTexas Engineering Experiment StationHexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a cyclic nitramine explosive, which has been widely used in military and civilian applications since World War II. The widespread use of RDX caused soil/groundwater contamination in the United States and other countries. Since RDX is toxic and a possible human carcinogen, remediation of RDX-contaminated sites is one of the major environmental engineering problems. Although anoxic/anaerobic biodegradation of RDX were observed, field application of RDX bioremediation remains a great challenge because of limited understanding of the microbial ecology of RDX-degraders, particular the interrelationships among active degraders, non-degraders, and their associated microbial community under different environmental conditions. In this research, carbon flow from 13C-labeled RDX to genetic makeup of active RDX-degraders will be traced by applying the methods of real-time-t-RFLP and Q-FAST, which were developed earlier by the PI. The principal objective of this research is to identify the diversity of RDX-utilizing bacteria under different environmental conditions. The research hypothesis is that RDX-utilizers, particularly those using RDX as a sole carbon source, are present in both clean and explosive-contaminated environments. This project will lead to the development of a range of key biomarkers relating to degradative activities of RDX to support remediation design and monitoring. Also, results of this project will make a significant scientific contribution to the fields of microbial ecology, applied microbiology, and environmental science and engineering. The knowledge derived by this research would guide the isolation efforts for new microorganisms that can be used for further physiological and biochemical studies as well as for bioaugmentation.