A comparative study of microbial communities in four soil slurries capable of RDX degradation using illumina sequencing.

Abstract

The nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) has contaminated many military sites. Recently, attempts to remediate these sites have focused on biostimulation to promote RDX biodegradation. Although many RDX degrading isolates have been obtained in the laboratory, little is known about the potential of microorganisms to degrade this chemical while existing in a soil community. The current study examined and compared the RDX degrading communities in four soil slurries to elucidate the potential of natural systems to degrade this chemical. These soils were selected as they had no previous exposure to RDX, therefore their microbial communities offered an excellent baseline to determine changes following RDX degradation. High throughput sequencing was used to determine which phylotypes experienced an increase in relative abundance following RDX degradation. For this, total genomic DNA was sequenced from (1) the initial soil, (2) soil slurry microcosms following RDX degradation and (3) control soil slurry microcosms without RDX addition. The sequencing data provided valuable information on which phylotypes increased in abundance following RDX degradation compared to control microcosms. The most notable trend was the increase in abundance of Brevundimonas and/or unclassified Bacillaceae 1 in the four soils studied. Although isolates of the family Bacillaceae 1 have previously been linked to RDX degradation, isolates of the genus Brevundimonas have not been previously associated with RDX degradation. Overall, the data suggest these two phylotypes have key roles in RDX degradation in soil communities.