在完全混合流反应器中，对 TCE 脱氯群落中的 Dehalococcoides mccartyi 进行结构动力学和转录组学分析。
Structural dynamics and transcriptomic analysis of Dehalococcoides mccartyi within a TCE-Dechlorinating community in a completely mixed flow reactor.
机构信息
Department of Civil and Environmental Engineering, University of California, Berkeley, CA, 94720-1710, USA.
DOE Joint Genome Institute, Walnut Creek, CA, USA.
出版信息
Water Res. 2019 Jul 1;158:146-156. doi: 10.1016/j.watres.2019.04.038. Epub 2019 Apr 19.
A trichloroethene (TCE)-dechlorinating community (CANAS) maintained in a completely mixed flow reactor was established from a semi-batch enrichment culture (ANAS) and was monitored for 400 days at a low solids retention time (SRT) under electron acceptor limitation. Around 85% of TCE supplied to CANAS (0.13 mmol d) was converted to ethene at a rate of 0.1 mmol d, with detection of low production rates of vinyl chloride (6.8 × 10 mmol d) and cis-dichloroethene (2.3 × 10 mmol d). Two distinct Dehalococcoides mccartyi strains (ANAS1 and ANAS2) were stably maintained at 6.2 ± 2.8 × 10 cells mL and 5.8 ± 1.2 × 10 cells mL, respectively. Electron balance analysis showed 107% electron recovery, in which 6.1% were involved in dechlorination. 16 S rRNA amplicon sequencing revealed a structural regime shift between ANAS and CANAS while maintaining robust TCE dechlorination due to similar relative abundances of D. mccartyi and functional redundancy among each functional guild supporting D. mccartyi activity. D. mccartyi transcriptomic analysis identified the genes encoding for ribosomal RNA and the reductive dehalogenases tceA and vcrA as the most expressed genes in CANAS, while hup and vhu were the most critical hydrogenases utilized by D. mccartyi in the community.
采用电子受体限制条件下低固体停留时间（SRT），从半分批富集培养物（ANAS）中建立了可连续完全混合流反应器中的三氯乙烯（TCE）脱氯群落（CANAS），并对其进行了 400 天的监测。在向 CANAS 中添加的约 85%的 TCE（0.13mmol d）以 0.1mmol d 的速率转化为乙烯，同时检测到氯乙烯（6.8×10 mmol d）和顺式二氯乙烯（2.3×10 mmol d）的低生成速率。两种不同的 Dehalococcoides mccartyi 菌株（ANAS1 和 ANAS2）分别稳定维持在 6.2±2.8×10 个细胞 mL 和 5.8±1.2×10 个细胞 mL。电子平衡分析表明，有 107%的电子得到回收，其中 6.1%参与了脱氯反应。16S rRNA 扩增子测序显示，尽管保持了强大的 TCE 脱氯作用，但 ANAS 和 CANAS 之间发生了结构状态转变，这是由于 D. mccartyi 的相对丰度相似，以及每个功能组之间的功能冗余支持 D. mccartyi 活性。D. mccartyi 转录组分析确定了编码核糖体 RNA 和还原脱卤酶 tceA 和 vcrA 的基因是 CANAS 中表达最多的基因，而 hup 和 vhu 是 D. mccartyi 在群落中利用的最重要的氢化酶。
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