Iron Sulfide Enhanced the Dechlorination of Trichloroethene by Dehalococcoides mccartyi Strain 195

Abstract

Iron sulfide (FeS) nanoparticles have great potential in environmental remediation. Using the representative species Dehalococcoides mccartyi strain 195 (Dhc 195), the effect of FeS on trichloroethene (TCE) dechlorination was studied with hydrogen and acetate as the electron donor and carbon source, respectively. With the addition of 0.2 mM Fe2+ and S2–, the dechlorination rate of TCE was enhanced from 25.46 ± 1.15 to 37.84 ± 1.89 μmol⋅L–1⋅day–1 by the in situ formed FeS nanoparticles, as revealed through X-ray diffraction. Comparing the tceA gene copy numbers between with FeS and without FeS, real-time polymerase chain reaction (PCR) indicated that the abundance of the tceA gene increased from (2.83 ± 0.13) × 107 to (4.27 ± 0.21) × 108 copies/ml on day 12. The transcriptional activity of key genes involved in the electron transport chain was upregulated after the addition of FeS, including those responsible for the iron–sulfur cluster assembly protein gene (DET1632) and transmembrane transport of iron (DET1503, DET0685), cobalamin (DET0685, DET1139), and molybdenum (DET1161) genes. Meanwhile, the reverse transcription of tceA was increased approximately five times on the 12th day. These upregulations together suggested that the electron transport of D. mccartyi strain 195 was enhanced by FeS for apparent TCE dechlorination. Overall, the present study provided an eco-friendly and effective method to achieve high remediation efficiency for organohalide-polluted groundwater and soil.

Recent advances and trends of trichloroethylene biodegradation: A critical review

“…Many researches have been devoted to investigate the synergetic effects of ZVI, mZVI, nZVI, nZVI-CMC, FeS and functional microorganisms in promoting TCE removal ( Figure 5A ; Wang and Tseng, 2009 ; Kocur et al, 2016 ; Wang et al, 2016 , 2020 ; Yang et al, 2018 ; Tian and Yu, 2020 ; Wu et al, 2020 ; Li et al, 2021 ; Yuan et al, 2022 ). The ZVI-bacteria combined system is not only a cost-effective technology, but also can greatly improve the TCE removal rate ( Wang and Tseng, 2009 ).…”

“…Moreover, co-encapsulated nZVI and Dehalococcoides species BAV1 system can degrade 10 mg/L of TCE within 3 h ( Shanbhogue et al, 2017 ). Additionally, FeS has been demonstrated can enhance electron transfer for TCE dechlorination by Dehalococcoides mccartyi strain 195 ( Li et al, 2021 ).…”

Interspecific Electron Transfer-Driven Oxytetracycline Degradation by Autotrophic Coculture of Sulfur-Oxidizing and Sulfate-Reducing Bacteria

“…At the same time, a SRB-mediated process has great potential for high antibiotic resistance and antibiotic removal. During the metabolism of SRB, sulfates need to be activated by ATP sulfurylase and then reduced by adenosine-5′-phosphosulphate reductase (APSR); the reductive capability of APSR was reported to play an important role in the biodegradation of many antibiotics such as PhAs, tetracyclines, quinolones, and sulfonamides. , More importantly, SRB anaerobically produced free sulfides, which would react with ferrous compounds (widely present in environments) to biosynthesize FeS. , With similar structures to iron–sulfur clusters (responsible for the transfer of electrons to metalloproteins), biosynthetic FeS could directly connect the discrete environment of space to accelerate intra/extracellular electron transport, promoting cell growth and upregulating gene expression related to intracellular and extracellular electron transport . As the key microorganisms affecting the global sulfur cycle, sulfur-oxidizing bacteria (SOB) and SRB often coexist in the natural environment and jointly participate in the degradation of antibiotics. , The metabolic pathways of antibiotics and the mechanisms of MIET and DIET remain unknown in their coculture systems under autotrophic conditions.…”