Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) a nitramine explosive, which has contaminated various military sites during its use, storage and manufacturing worldwide. As RDX is a recalcitrant, less soluble and toxic to human beings and other organisms, it is essential to remediate the contaminated sites. In the current investigation, authors have explored the potential of two indigenous microbes i.e., Bacillus toyonensis (isolate No. WS4-TSB-3, MTCC No. 12857) and Paenibacillus dendritiformis (isolate No. S10-TSA-3, MTCC No. 12859) isolated from an explosive manufacturing facility in north India, for the degradation of RDX in aqueous medium. Furthermore, RDX degradation has been optimized using response surface methodology (RSM) in a 15 days experiment at concentration of 20, 40, and 60 mg/L. It was found that various factors such as initial concentration of RDX, inoculum volume (2, 4 and 6%) and time (5, 10 and 15 days) had impact on transformation and degradation of contaminant. Samples were analyzed using high performance liquid chromatography (HPLC) and intermediate products were identified using LC-MS/MS. Maximum RDX removal of 81.6 ± 1.3 and 84.7 ± 0.9% for Bacillus toyonensis (isolate No. WS4-TSB-3) and Paenibacillus dendritiformis (isolate No. S10-TSA-3), respectively, was observed on 15th day at 40 mg/L initial concentration. During the degradation Hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), Hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), 4-Nitro-2,4-diazabutanal, Bis(hydroxymethyl)nitramine and nitrite were identified as intermediate products. The findings of the investigation suggest that both the microbes have the potential to degrade RDX in the aqueous medium and can be used for up-scaling the degradation of RDX on explosive contaminated sites.

中文翻译：

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有氧条件下六水-1,3,5-三硝基-1,3,5-三嗪（RDX）的优化和降解研究

六氢-1,3,5-三硝基-1,3,5-三嗪（RDX）硝胺炸药，在全球范围内的使用，存储和制造过程中，已经污染了各个军事场所。由于RDX具有顽强性，对人类和其他生物的溶解性和毒性较小，因此必须对污染部位进行修复。在当前的调查中，作者探索了两种本土微生物的潜力，即toonensis芽孢杆菌（分离号WS4-TSB-3，MTCC编号12857）和树状芽孢杆菌从印度北部的一家炸药生产厂分离而来的产品（编号S10-TSA-3，MTCC编号12859），用于在水性介质中降解RDX。此外，在15天的浓度，20、40和60 mg / L的实验中，使用响应表面方法（RSM）对RDX的降解进行了优化。发现各种因素，如RDX的初始浓度，接种量（2、4和6％）和时间（5、10和15天）都对污染物的转化和降解产生影响。使用高效液相色谱（HPLC）分析样品，并使用LC-MS / MS鉴定中间产物。永生芽孢杆菌（分离号WS4-TSB-3）和树状芽孢杆菌的最大RDX去除率为81.6±1.3和84.7±0.9％在第15天以40 mg / L的初始浓度分别观察到（分离号S10-TSA-3）。在降解过程中，六氢-1-亚硝基-3,5-二硝基-1,3,5-三嗪（MNX），六氢-1,3-二亚硝基-5-硝基-1,3,5-三嗪（DNX），4 -硝基-2,4-二氮杂丁醛，双（羟甲基）硝胺和亚硝酸盐被鉴定为中间产物。调查结果表明，两种微生物均具有降解水性介质中RDX的潜能，可用于扩大爆炸性污染部位RDX的降解。