Department of Civil and Environmental Engineering, National University of Singapore, 117576, Singapore.
Environ Sci Technol. 2020 Jul 21;54(14):8750-8759. doi: 10.1021/acs.est.0c00993. Epub 2020 Jun 29.
Cocontamination by chloroform and chloroethenes often confounds bioremediation efforts. Here, we describe strain GEO12 that dechlorinates trichloroethene to ethene in 14 μM (1.6 mg·L) chloroform. The same chloroform concentration effectively inhibited dechlorination in strains ANAS2, 11a, and BAV1. Successive transfers of strain GEO12 in increasing concentrations of chloroform led to culture GEO12CF that tolerated 83 μM (10 mg·L) chloroform. The genome of strain GEO12 revealed seven reductive dehalogenase homologous () genes, including and . Transcriptional analyses showed that chloroform (45 μM; 5.3 mg·L) in culture GEO12CF enhanced the transcription of to a statistically significant degree (the median increase was 55.4 transcripts per 10 16S rRNA, CI = [12.9, 125]). The increase of transcripts in the presence of chloroform (45 μM; 5.3 mg·L) in culture GEO12CF was not statistically significant because the CI range spanned 0 (the median increase was 109 transcripts per 10 16S rRNA, CI = [-13.6, 246]). Inhibition of dehalogenation by chloroform is often seen in , but the mechanism remains unknown. Our results suggest that culture GEO12CF may overcome chloroform inhibition by upregulation. The chloroform-adapted culture GEO12CF provides insights into the metabolic flexibility of and could be used to fight chloroethene contamination where chloroform is a cocontaminant.
三氯乙烷在氯仿中的共污染常常使生物修复工作复杂化。在这里，我们描述了一株能够将三氯乙烯脱氯为乙烯的 GEO12 菌株，其在 14 μM（1.6 mg·L）氯仿中的脱氯率为 14 μM（1.6 mg·L）。相同的氯仿浓度有效地抑制了菌株 ANAS2、11a 和 BAV1 的脱氯作用。将 GEO12 菌株连续传代到氯仿浓度增加的情况下，导致培养物 GEO12CF 能够耐受 83 μM（10 mg·L）的氯仿。GEO12 菌株的基因组显示了七个还原脱卤酶同源基因（），包括和。转录分析表明，培养物 GEO12CF 中的氯仿（45 μM；5.3 mg·L）在统计学上显著增强了的转录（中位数增加了 55.4 个转录物/10 个 16S rRNA，CI=[12.9，125]）。在培养物 GEO12CF 中存在氯仿（45 μM；5.3 mg·L）时，转录物的增加并不显著，因为 CI 范围跨越了 0（中位数增加了 109 个转录物/10 个 16S rRNA，CI=[-13.6，246]）。氯仿对脱卤作用的抑制在属中很常见，但机制尚不清楚。我们的结果表明，培养物 GEO12CF 可能通过上调来克服氯仿的抑制作用。适应氯仿的培养物 GEO12CF 为属的代谢灵活性提供了新的认识，并可用于对抗氯仿作为共污染物的氯代烯烃污染。
