Facultad de Ciencias, Departamento de Biología, Unidad de Saneamiento y Biotecnología Ambiental (USBA), Pontificia Universidad Javeriana, Carrera 7 No. 43-82, Bogotá, DC, Colombia.
Facultad de Ciencias, Departamento de Biología, Biología de Plantas y Sistemas Productivos, Pontificia Universidad Javeriana, Bogotá, Colombia.
World J Microbiol Biotechnol. 2020 Nov 28;36(12):190. doi: 10.1007/s11274-020-02962-8.
The nitrated compounds 2,4-dinitrotoluene (2,4-DNT), 2,4,6-trinitrotoluene (TNT), and pentaerythritol tetranitrate (PETN) are toxic xenobiotics widely used in various industries. They often coexist as environmental contaminants. The aims of this study were to evaluate the transformation of 100 mg L of TNT, 2,4-DNT, and PETN by Raoultella planticola M30b and Rhizobium radiobacter M109c and identify enzymes that may participate in the transformation. These strains were selected from 34 TNT transforming bacteria. Cupriavidus metallidurans DNT was used as a reference strain for comparison purposes. Strains DNT, M30b and M109c transformed 2,4-DNT (100%), TNT (100, 94.7 and 63.6%, respectively), and PETN (72.7, 69.3 and 90.7%, respectively). However, the presence of TNT negatively affects 2,4-DNT and PETN transformation (inhibition > 40%) in strains DNT and M109c and fully inhibited (100% inhibition) 2,4-DNT transformation in R. planticola M30b.Genomes of R. planticola M30b and R. radiobacter M109c were sequenced to identify genes related with 2,4-DNT, TNT or PETN transformation. None of the tested strains presented DNT oxygenase, which has been previously reported in the transformation of 2,4-DNT. Thus, unidentified novel enzymes in these strains are involved in 2,4-DNT transformation. Genes encoding enzymes homologous to the previously reported TNT and PETN-transforming enzymes were identified in both genomes. R. planticola M30b have homologous genes of PETN reductase and xenobiotic reductase B, while R. radiobacter M109c have homologous genes to GTN reductase and PnrA nitroreductase. The ability of these strains to transform explosive mixtures has a potentially biotechnological application in the bioremediation of contaminated environments.
硝化物 2,4-二硝基甲苯（2,4-DNT）、2,4,6-三硝基甲苯（TNT）和季戊四醇四硝酸酯（PETN）是广泛应用于各行业的有毒异生物质。它们通常作为环境污染物共存。本研究旨在评估 Raoultella planticola M30b 和 Rhizobium radiobacter M109c 对 100mg/L TNT、2,4-DNT 和 PETN 的转化，并鉴定可能参与转化的酶。这些菌株是从 34 株 TNT 转化菌中筛选出来的，Cupriavidus metallidurans DNT 被用作参考菌株进行比较。菌株 DNT、M30b 和 M109c 转化了 2,4-DNT（100%）、TNT（100%、94.7%和 63.6%）和 PETN（72.7%、69.3%和 90.7%）。然而，TNT 的存在会对 DNT 和 PETN 的转化产生负面影响（抑制率＞40%），在菌株 DNT 和 M109c 中，完全抑制了 2,4-DNT 的转化，而在 R. planticola M30b 中则完全抑制了 2,4-DNT 的转化。对 R. planticola M30b 和 R. radiobacter M109c 的基因组进行测序，以鉴定与 2,4-DNT、TNT 或 PETN 转化相关的基因。在所有测试的菌株中都没有检测到先前报道的 2,4-DNT 转化中所涉及的 DNT 加氧酶。因此，这些菌株中涉及 2,4-DNT 转化的是未知的新型酶。在两个基因组中都鉴定到与先前报道的 TNT 和 PETN 转化酶同源的基因编码酶。R. planticola M30b 具有 PETN 还原酶和异生物质还原酶 B 的同源基因，而 R. radiobacter M109c 具有 GTN 还原酶和 PnrA 硝基还原酶的同源基因。这些菌株转化爆炸混合物的能力在污染环境的生物修复方面具有潜在的生物技术应用。
