Microbial ecology of two distinct biological systems: 2,4,6-trinitrotoluene (TNT)-degrading bioreactors and the termite gut.

摘要

Energetic compounds have important roles in military and civilian applications, and their production represents a considerable portion of the chemical manufacturing industry. Decommissioning and cleanup of these materials has led to concerns about explosive hazards associated with residual energetics still present on the surfaces of ordnance and explosives scrap. Here, the use of an alternative anaerobic microbiological bioslurry system to decontaminate energetics from the surfaces of metal scrap is described. HPLC and GC-MS analyses from bench-scale bioslurry studies, using a soil microbial inoculum, indicated that this is a highly effective approach for the removal of 2,4,6-trinitrotoluene (TNT) from contaminated liquids, contaminated model metal scrap, and decommissioned mortar rounds. A portable ion mobility spectrometer was also employed for the detection of residual explosives on the surfaces of the scrap.; Little is known about the combination or sequence of microbes responsible for degradation and mineralization of TNT in nature or in bioreactors. The hypothesis of this research was that molecular characterization of the bioreactor community might help us elucidate the temporal composition of the TNT-degrading consortium, allowing us to identify important indicator species, species ratios, or population trends as a means of assessing the health or status of full-scale bioreactors. Our results indicated there were no identifiable population differences between TNT-contaminated and non-contaminated bioreactors and no substantial population shifts in the TNT-contaminated bioreactors throughout the course of TNT degradation. This information, coupled with pure culture data revealed that the bioreactor system used in these studies was not only stable, but also a system in which pure culture studies have great utility.; Termites have an essential role in carbon, nitrogen, and sulfur cycles in nature. All termites are dependent upon a symbiotic relationship with gut prokaryotes. In this research we describe a quick method to isolate and purify bacterial DNA from the termite gut and we exemplified the importance of standardizing culture/collection methods by the use of 16S rDNA profiling to demonstrate the variation in gut bacterial populations between termites cultivated in sterile versus non-sterile conditions. Such information will help provide insight into microbial and insect physiology, ecology, and biodegradation chemistry.