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

六氢-1,3,5-三硝基-1,3,5-三嗪（RDX）是一种环硝胺炸药，自第二次世界大战以来被广泛应用于军事和民用。RDX的广泛使用在美国和其他国家造成了土壤/地下水污染。由于RDX是有毒的，是一种可能的人类致癌物，RDX污染场地的修复是主要的环境工程问题之一。尽管已经观察到RDX的缺氧/厌氧生物降解，但由于对RDX降解物的微生物生态，特别是活性降解物、非降解物及其相关微生物群落在不同环境条件下的相互关系的了解有限，RDX生物修复的现场应用仍然是一个巨大的挑战。在本研究中，将采用PI早期开发的实时t- rflp和Q-FAST方法，追踪从13c标记的RDX到活性RDX降解物的基因组成的碳流。本研究的主要目的是鉴定不同环境条件下利用rdx的细菌的多样性。研究假设RDX的利用者，特别是那些使用RDX作为唯一碳源的人，既存在于清洁环境中，也存在于爆炸物污染的环境中。该项目将开发一系列与RDX降解活动相关的关键生物标志物，以支持修复设计和监测。本项目的研究成果将对微生物生态学、应用微生物学、环境科学与工程等领域做出重要的科学贡献。本研究获得的知识将指导分离新微生物的工作，这些微生物可用于进一步的生理和生化研究以及生物增强。

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.