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Biotransformation products and mineralization potential for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in abiotic versus biological degradation pathways with anthraquinone-2,6-disulfonate (AQDS) and Geobacter metallireducens.
Biodegradation ( IF 3.6 ) Pub Date : 2008-02-02 , DOI: 10.1007/s10532-008-9175-5
Man Jae Kwon 1 , Kevin Thomas Finneran
Affiliation  

This study investigated extracellular electron shuttle-mediated RDX biodegradation and the distribution of ring cleavage metabolites generated by biological degradation (cells) versus the products formed by abiotic degradation (reduced electron shuttles), and when the two pathways were acting simultaneously. All pathways were influenced by pH. Buffered suspensions (pH 6.8/7.9/9.2) were performed with cell-free anthrahydroquinone-2,6-disulfonate as the sole electron donor, cells (Geobacter metallireducens) + acetate, or cells/acetate + anthraquinone-2,6-disulfonate as an electron shuttle. The metabolites identified included methylenedinitramine, formaldehyde, nitrous oxide, nitrite, ammonium and carbon dioxide. As pH increased, the rates of RDX reduction by AH(2)QDS also increased. Cells alone reduced RDX faster at the lower pH values. However, at all pH the rates of the electron shuttle-mediated pathways were consistently the fastest, and the proportion of carbon present as formaldehyde, which is a precursor to mineralization, was highest in the presence of electron shuttles. Formaldehyde accounted for 45/51/54% of the carbon in electron shuttle amended cell suspensions as opposed to 13/42/45% of carbon without shuttles at the pH 6.8/7.9/9.2, respectively. Approximately 7-20% of RDX was mineralized to CO(2) in the presence of cells at all pH tested; AQDS increased the extent of (14)CO(2) produced. Nitrous oxide and nitrite were end products in the strictly abiotic pathway, but nitrite was depleted in the presence of cells to form ammonium. Understanding the different products formed in the abiotic versus biological pathways and the influence of pH is critical to developing mixed biotic-abiotic remediation strategies for RDX.

中文翻译:

非生物对生物降解途径中的六氢-1,3,5-三硝基-1,3,5-三嗪(RDX)的生物转化产物和矿化潜力与2,6-蒽磺酸蒽醌(AQDS)和金属还原杆菌一起。

这项研究调查了细胞外电子穿梭介导的RDX生物降解以及生物降解(细胞)与非生物降解(还原的电子穿梭)形成的产物以及两种途径同时起作用时环裂解代谢产物的分布。所有途径均受pH影响。缓冲液悬浮液(pH 6.8 / 7.9 / 9.2)以无细胞的2,6-二氢蒽醌作为唯一的电子供体,细胞(金属还原杆菌)+乙酸盐,或以细胞/乙酸盐+ 2,6-二磺酸蒽醌的溶液进行。电子飞梭。鉴定出的代谢物包括亚甲基二乙胺,甲醛,一氧化二氮,亚硝酸盐,铵和二氧化碳。随着pH值的增加,AH(2)QDS对RDX的还原率也增加了。单独的细胞在较低的pH值下能更快地降低RDX。然而,在所有pH值下,电子穿梭介导途径的速率始终是最快的,存在电子穿梭时,作为矿化前体的甲醛中存在的碳比例最高。甲醛占经电子穿梭修正的细胞悬浮液中碳的45/51/54%,而在pH 6.8 / 7.9 / 9.2下,无穿梭的碳分别占13/42/45%。在所有测试的pH下,在有细胞存在的情况下,约7-20%的RDX会矿化为CO(2)。AQDS增加了(14)CO(2)产生的程度。一氧化二氮和亚硝酸盐是严格的非生物途径的终产物,但亚硝酸盐在细胞存在时被消耗掉而形成铵。
更新日期:2019-11-01
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