Enhancement of anaerobic carbon tetrachloride biotransformation in methanogenic sludge with redox active vitamins

Guerrero–Barajas, Claudia; Field, Jim A.

doi:10.1007/s10532-004-0638-z

Cited by 20 publications

(18 citation statements)

References 41 publications

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“…The highest DCM levels in the other treatments ranged from 2 to 26 lM. Perchloroethylene (PCE) was also observed at low concentrations as a CT-degradation side product in agreement with earlier observations (Cervantes et al 2004;Guerrero-Barajas & Field 2005a). Concentrations of PCE ranged from 0.05 to 2.53 lM on day 18.…”

Section: Screening Of Vitamin B 12 Precursorssupporting

confidence: 91%

“…The first order rate constants and the residual concentration of CT on day 8 and day 18 are shown in Table 2. The Table illustrates that CT degradation occurred slowly in the negative control; while the rate was 11.5-fold faster in the positive control in accordance with the previous study (Guerrero-Barajas & Field 2005a). Of all the precursors tested, the best response was obtained with PB, providing a rate constant that was 3-fold greater than that of the negative control with cobalt (Table 2, Figure 1).…”

Section: Screening Of Vitamin B 12 Precursorssupporting

confidence: 88%

“…Radiolabeled [ 14 C]CT was shown to be converted to 14 CO 2 as a major product in an unadapted methanogenic consortium (Van Eekert et al 1998). In our previous work, we have demonstrated that vitamin B 12 additions to a methanogenic consortium dramatically increased the mineralization of CT accounting for an increased molar recovery of inorganic chloride per CT converted (Guerrero-Barajas & Field 2005a). The increased molar recovery of chloride would indicate that vitamin B 12 promotes the reductive hydrolysis reactions.…”

Section: Effect Of Pb On the Mineralization Of Ctmentioning

confidence: 93%

“…Molar ratios as low as 0.005 CNB 12 :CT had very significant effects on the CT degradation rate (Guerrero-Barajas & Field 2005a). The substoichiometric ratios would suggest redox cycling of vitamin B 12 between oxidized and reduced forms.…”

Section: Introductionmentioning

confidence: 95%

“…1995). CNB 12 and HOB 12 , supplied at a molar ratio of 0.1 vitamin:CT, increased CT bioconversion rates by 13.3-and 13.6-fold; respectively, in an unadapted methanogenic consortium (Guerrero-Barajas & Field 2005a). Vitamin B 12 also stimulated the chloroform (CF) dechlorination rates in an anaerobic DCMdegrading enrichment culture (Becker & Freedman 1994) as well as in an unadapted methanogenic consortium (Guerrero-Barajas & Field 2005b).…”

Section: Introductionmentioning

confidence: 99%

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Enhanced anaerobic biotransformation of carbon tetrachloride with precursors of vitamin B12 biosynthesis

Guerrero–Barajas

Field

2006

Biodegradation

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Relatively low concentrations of Vitamin B(12) are known to accelerate the anaerobic biotransformation of carbon tetrachloride (CT) and chloroform (CF). However, the addition of vitamin B(12) for field-scale bioremediation is expected to be costly. The present study considered a strategy to generate vitamin B(12) by addition of biosynthetic precursors. One of the precursors, porphobilinogen (PB) involved in the formation of the corrin ring, significantly increased the CT biotransformation rates by 2.7-, 8.8- and 10.9-fold when supplemented at 160, 500 and 900 microM, respectively. A positive control with 10 microM of vitamin B(12) resulted in a 5.9-fold increase in the CT-bioconversion rate. PB additions provided high molar yields of inorganic chloride (57% of CT organochlorine), comparable to that obtained with vitamin B(12) supplemented cultures. The primary substrate, methanol, known to induce vitamin B(12) production in methanogens and acetogens, was required for PB to have a significant impact on CT conversion. The observation suggests that PB's role was due to stimulating vitamin B(12) biosynthesis. The present study therefore provides insights on how to achieve vitamin B(12) enhanced rates of CT bioremediation through the use of less complex compounds that are precursors of vitamin B(12). Although PB is a costly chemical, its large impact points to corrin ring formation as the rate-limiting step.

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Section: Screening Of Vitamin B 12 Precursorssupporting

confidence: 91%

Section: Screening Of Vitamin B 12 Precursorssupporting

confidence: 88%

Section: Effect Of Pb On the Mineralization Of Ctmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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Enhanced anaerobic biotransformation of carbon tetrachloride with precursors of vitamin B12 biosynthesis

Guerrero–Barajas

Field

2006

Biodegradation

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Microbial reductive dechlorination of trichloroethene to ethene with electrodes serving as electron donors without the external addition of redox mediators

Aulenta

Canosa

Reale

et al. 2009

Biotech & Bioengineering

145

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In situ bioremediation of industrial chlorinated solvents, such as trichloroethene (TCE), is typically accomplished by providing an organic electron donor to naturally occurring dechlorinating populations. In the present study, we show that TCE dechlorinating bacteria can access the electrons required for TCE dechlorination directly from a negatively polarized (-450 mV vs. SHE) carbon paper electrode. In replicated batch experiments, a mixed dechlorinating culture, also containing Dehalococcoides spp., dechlorinated TCE to cis-dichloroethene (cis-DCE) and lower amounts of vinyl chloride (VC) and ethene using the polarized electrode as the sole electron donor. Conversely, neither VC nor ethene formation occurred when a pure culture of the electro-active microorganism Geobacter lovleyi was used, under identical experimental conditions. Cyclic voltammetry tests, carried out on the filter-sterilized supernatant of the mixed culture revealed the presence of a self-produced redox mediator, exhibiting a midpoint potential of around -400 mV (vs. SHE). This yet unidentified redox-active molecule appeared to be involved in the extracellular electron transfer from the electrode to the dechlorinating bacteria. The ability of dechlorinating bacteria to use electrodes as electron donors opens new perspectives for the development of clean, versatile, and efficient bioremediation systems based on a controlled subsurface delivery of electrons in support of biodegradative metabolisms and provides further evidence on the possibility of using conductive materials to manipulate and control a range of microbial bioprocesses.

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Enhanced nitrobenzene biotransformation by graphene‐anaerobic sludge composite

Wang

Liu

et al. 2013

J of Chemical Tech & Biotech

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BACKGROUND Traditional anaerobic bioprocesses have failed to achieve the efficient biotransformation of nitrobenzene. Thus, graphene‐anaerobic sludge composite as a novel biocatalyst was proposed for the enhancement of nitrobenzene biotransformation. RESULTS Reduced graphene oxide/anaerobic sludge (RGO/AS) composite presented good settling performance when graphene oxide (GO) was added into an AS system for 24 h cultivation. The presence of RGO resulted in enhanced nitrobenzene biotransformation by AS, and the highest removal efficiency of nitrobenzene was observed with initial GO (3–5 µm) vs sludge ratio of 0.075 (w/w). Dehydrogenase activity in the RGO/AS system increased approximately 2‐fold over that in the AS system and redox active species appeared in supernatant from the RGO/AS system. The ratio of acetate to propionate increased in the RGO/AS system during glucose fermentation, and nitrobenzene biotransformation by both AS and RGO/AS systems was independent of methanogenesis, but dependent on acetogenesis. Moreover, bound and free extracellular polymeric substances (EPS) from RGO/AS composite were involved in direct biotransformation of nitrobenzene, and bound EPS might interact with secreted redox active species to accelerate nitrobenzene biotransformation by extracellular electron transfer. CONCLUSION RGO/AS composite was efficient for the treatment of nitrobenzene wastewater. © 2013 Society of Chemical Industry

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Enhancement of anaerobic carbon tetrachloride biotransformation in methanogenic sludge with redox active vitamins

Cited by 20 publications

References 41 publications

Enhanced anaerobic biotransformation of carbon tetrachloride with precursors of vitamin B12 biosynthesis

Enhanced anaerobic biotransformation of carbon tetrachloride with precursors of vitamin B12 biosynthesis

Microbial reductive dechlorination of trichloroethene to ethene with electrodes serving as electron donors without the external addition of redox mediators

Enhanced nitrobenzene biotransformation by graphene‐anaerobic sludge composite

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