Enhancing the biological reductive dechlorination of trichloroethylene with PHA from mixed microbial cultures (MMC)

Ensuring the continued success of a mulch biowall at a trichloroethylene‐contaminated superfund site: Lessons learned

“…In addition to testing for the presence of DHC, the functional genes encoding for the enzymes responsible for the dechlorination of TCE and VC were also tested to ensure other bacteria with the potential to conduct each of the dechlorination steps were considered. The tceA (encoding the dechlorination of TCE to ethene), vcrA (encoding dechlorination of TCE to ethene), and bvcA (encoding the dechlorination of VC to ethene) genes were present in the site, although in small concentrations (Amanat et al, 2022;Hug & Edwards, 2013;Molenda et al, 2016;Rossi et al, 2022). Lu et al (2006) proposed a criterion of 10,000 DHC cells/mL for potential field-based biological reductive dechlorination.…”

Synthetic and Natural Surfactants for Potential Application in Mobilization of Organic Contaminants: Characterization and Batch Study

“…A series of isothermal batch experiments with PWB/contaminant/surfactant were conducted at room temperature (23 ± 2 • C) and pressure in 20 mL batch reactors (VWR International glass vials, Milan, Italy), using different amounts of sorbent material (10, 20, 50, 80, 100, and 200 mg), and 50 mg L -1 of contaminant solution. The contaminated solutions were prepared in distilled water and stored in gas-tight collapsible Tedral bags ® (Supelco, Bellefonte, PA, USA), which prevent the formation of headspace and ensure constant maintenance of the concentration of the solution containing volatile compounds [50].…”

Degradation of 1,2-dichloroethane in real polluted groundwater by using enriched bacterial consortia in aerobic and anaerobic laboratory-scale conditions

“…Generally, low-chlorinated compounds are degraded through a oxidative direct pathway; in contrast, polychlorinated compounds can be effectively degraded via biological reductive dechlorination (Furukawa et al, 2002), provided that specific microorganisms and available electron donors are present (which is usually the limiting factor in natural reductive biodegradation processes) (Baric et al, 2012(Baric et al, , 2014. The biological reductive dechlorination (BRD) is a natural process where indigenous microorganisms present in the groundwater ecosystem through an anaerobic multi-step reaction convert highly chlorinated parent compounds to less chlorinated daughter products and finally to non-toxic end products, like as ethene and ethane (Xiao et al, 2020;Lin et al, 2021;Amanat et al, 2022). In this anaerobic respiratory process, called dehalorespiration, organohalide respiring bacteria (OHRB) utilize the chlorinated compounds as terminal electron acceptors (Hug et al, 2013).…”

“…In this anaerobic respiratory process, called dehalorespiration, organohalide respiring bacteria (OHRB) utilize the chlorinated compounds as terminal electron acceptors (Hug et al, 2013). BRD is an electron consuming process and it is often limited by the lack of suitable electron donors that results in an incomplete process and leads to the accumulation of undesired by-products (Li et al, 2021;Yan et al, 2021;Amanat et al, 2022). Therefore, it is possible to enhance and sustain BRD through the addition of fermentable substrates by supplying the microorganisms with sources of electron donors (e.g., hydrogen, butyrate, lactate).…”

“…To date, poly-β-hydroxybutyrate (PHB) derived both from pure and mixed microbial culture has proven to be effective as a slow-release electron donor for the reductive dechlorination process (Aulenta et al, 2008;Pierro et al, 2017;Amanat et al, 2020Amanat et al, , 2021Amanat et al, , 2022 and various studies (Baric et al, 2012(Baric et al, , 2014Matturro et al, 2018;Amanat et al, 2021Amanat et al, , 2022 confirmed the feasibility to use it as a reactive medium in a PRB. Heretofore, the most common way to produce PHB is to use pure bacterial cultures and selected substrates; however, this involves high costs and makes the production process economically unsustainable (Ivanov et al, 2014;Villano et al, 2014).…”