Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai, 980-8579, Japan; Graduate School of Life Science, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, 980-8577, Japan.
Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai, 980-8579, Japan; Department of Biological Sciences, Marquette University, Milwaukee, WI, 53233, USA; Department of Environmental Science and Resource Management, Mawlana Bhashani Science and Technology University, Santosh, Tangail, 1902, Bangladesh.
Chemosphere. 2023 Apr;319:137988. doi: 10.1016/j.chemosphere.2023.137988. Epub 2023 Jan 29.
Carbon tetrachloride (CT) is a recalcitrant and high priority pollutant known for its toxicity, environmental prevalence, and inhibitory activities. Although much is known about anaerobic CT biodegradation, microbial degradation of CT under aerobic conditions has not yet been reported. This study reports for the first time the enrichment of a stable aerobic CT-degrading bacterial consortium, from a CT-contaminated groundwater sample, capable of co-metabolically degrading 30 μM of CT within a week. A Pseudomonas strain (designated as Stari2) that is the predominant bacterium in this consortium was isolated, and further characterization showed that this bacterium can tolerate and co-metabolically degrade up to 5 mM of CT under aerobic conditions in the presence of different carbon/energy sources. The CT biodegradation profiles of strain Stari2 and the consortium were found to be identical, while no significant positive correlation between strain Stari2 and other bacteria was observed in the consortium during the period of higher CT biodegradation. These results confirmed that the isolated Pseudomonas strain Stari2 is the key player in the consortium catalyzing the biodegradation of CT. No chloroform (CF) or other chlorinated compound was detected during the cometabolism of CT. The whole genome sequencing of strain Stari2 showed that it is a novel Pseudomonas species. The findings demonstrated that biodegradation of CT under aerobic conditions is feasible, and the isolated CT-degrader Pseudomonas sp. strain Stari2 has a great potential for in-situ bioremediation of CT-contaminated environments.
四氯化碳（CT）是一种难降解的高优先级污染物，以其毒性、环境普遍性和抑制活性而闻名。尽管人们对厌氧 CT 生物降解了解很多，但有氧条件下 CT 的微生物降解尚未得到报道。本研究首次报道了从 CT 污染的地下水样品中富集的稳定好氧 CT 降解细菌群落，该群落能够在一周内共代谢降解 30 μM 的 CT。从该群落中分离出一株优势菌，命名为 Stari2，进一步的表征表明，该菌能够在有氧条件下耐受并共代谢降解高达 5 mM 的 CT，同时存在不同的碳/能源源。发现菌株 Stari2 和群落的 CT 生物降解谱是相同的，而在 CT 生物降解率较高的时期，在群落中没有观察到菌株 Stari2 与其他细菌之间存在显著的正相关。这些结果证实，分离出的假单胞菌菌株 Stari2 是该群落中催化 CT 生物降解的关键因素。在 CT 的共代谢过程中没有检测到三氯甲烷（CF）或其他氯化化合物。菌株 Stari2 的全基因组测序表明，它是一种新型的假单胞菌。研究结果表明，有氧条件下 CT 的生物降解是可行的，分离出的 CT 降解菌假单胞菌菌株 Stari2 具有原位修复 CT 污染环境的巨大潜力。
