Department of Environmental Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea.
J Microbiol Biotechnol. 2023 Jul 28;33(7):886-894. doi: 10.4014/jmb.2301.01007. Epub 2023 Apr 14.
During the rhizoremediation of diesel-contaminated soil, methane (CH), a representative greenhouse gas, is emitted as a result of anaerobic metabolism of diesel. The application of methantrophs is one of solutions for the mitigation CH emissions during the rhizoremediation of diesel-contaminated soil. In this study, CH-oxidizing rhizobacteria, sp. JHTF4 and sp. JHM8, were isolated from rhizosphere soils of tall fescue and maize, respectively. The maximum CH oxidation rates for the strains JHTF4 and JHM8 were 65.8 and 33.8 mmol·g-DCW·h, respectively. The isolates JHTF4 and JHM8 couldn't degrade diesel. The inoculation of the isolate JHTF4 or JHM8 significantly enhanced diesel removal during rhizoremediation of diesel-contaminated soil planted with maize for 63 days. Diesel removal in the tall fescue-planting soil was enhanced by inoculating the isolates until 50 days, while there was no significant difference in removal efficiency regardless of inoculation at day 63. In both the maize and tall fescue planting soils, the CH oxidation potentials of the inoculated soils were significantly higher than the potentials of the non-inoculated soils. In addition, the gene copy numbers of , responsible for CH oxidation, in the inoculated soils were significantly higher than those in the non-inoculated soils. The gene copy numbers ratio of to 16S rDNA (the ratio of methanotrophs to total bacteria) in soil increased during rhizoremediation. These results indicate that the inoculation of sp. JHTF4 and sp. JHM8, is a promising strategy to minimize CH emissions during the rhizoremediation of diesel-contaminated soil using maize or tall fescue.
在柴油污染土壤的根际修复过程中，由于柴油的厌氧代谢，会产生甲烷（CH）这种代表性的温室气体。应用甲烷营养菌是减少柴油污染土壤根际修复过程中 CH 排放的解决方案之一。本研究从高羊茅和玉米根际土壤中分别分离到一株 CH 氧化根瘤菌，命名为 JHTF4 和 JHM8。菌株 JHTF4 和 JHM8 的最大 CH 氧化速率分别为 65.8 和 33.8 mmol·g-DCW·h。这两株菌不能降解柴油。在接种 JHTF4 或 JHM8 的情况下，玉米根际修复柴油污染土壤 63 天，柴油去除率显著提高。接种 JHTF4 或 JHM8 可提高高羊茅根际修复柴油污染土壤的柴油去除率，直到第 50 天，但第 63 天的去除效率没有显著差异。在玉米和高羊茅种植土壤中，接种土壤的 CH 氧化潜力明显高于未接种土壤。此外，接种土壤中负责 CH 氧化的 基因拷贝数明显高于未接种土壤。根际修复过程中，接种土壤中 与 16S rDNA 的基因拷贝数比值（甲烷营养菌与总细菌的比值）增加。这些结果表明，接种 JHTF4 和 JHM8 是一种很有前途的策略，可以减少使用玉米或高羊茅进行柴油污染土壤根际修复过程中的 CH 排放。
