Cobalamin-enhanced anaerobic biotransformation of carbon tetrachloride

Hashsham, Syed A.; Scholze, Richard J; Feedman, David L.

doi:10.1021/es00011a023

Cited by 45 publications

(50 citation statements)

References 31 publications

(62 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Addition of vitamin B 12 also shifts the pathway away from reductive dechlorination and toward hydrolytic and substitutive reactions, forming CO, CO 2 , and organic acids as the major products (8,23,24). With low levels of B 12 added (3 to 5% molar ratios of CF), an enrichment culture grown on dichloromethane (DCM) as the sole substrate (8) and a lactate-grown sulfate-reducing enrichment culture (18) were able to biotransform up to 260 mg/liter and 270 mg/liter CF, respectively.…”

mentioning

confidence: 99%

Anaerobic Biotransformation of High Concentrations of Chloroform by an Enrichment Culture and Two Bacterial Isolates

Shan¹,

Kurtz

Mykytczuk

et al. 2010

Appl Environ Microbiol

View full text Add to dashboard Cite

A fermentative enrichment culture (designated DHM-1) was developed that is capable of cometabolically biotransforming high concentrations of chloroform (CF) to nontoxic end products. Two Pantoea spp. were isolated from DHM-1 that also possess this dechlorination capability. Following acclimation to increasing levels of CF, corn syrup-grown DHM-1 was able to transform over 500 mg/liter CF in the presence of vitamin B 12 (approximately 3% of CF on a molar basis) at a rate as high as 22 mg/liter/day in a mineral salts medium. CO, CO 2 , and organic acids were the predominant biodegradation products, suggesting that hydrolytic reactions predominate during CF transformation. DHM-1 was capable of growing on corn syrup in the presence of high concentrations of CF (as may be present near contaminant source zones in groundwater), which makes it a promising culture for bioaugmentation. Strains DHM-1B and DHM-1T transform CF at rates similar to that of the DHM-1 enrichment culture. The ability of these strains to grow in the presence of high concentrations of CF appears to be related to alteration of membrane fluidity or homeoviscous and homeophasic adaptation.Chloroform (CF) is a toxic organic compound that is frequently detected in groundwater. In the 2007 "CERCLA Priority List of Hazardous Substances," CF ranks eleventh overall and is the third highest among chlorinated organics after vinyl chloride and polychlorinated biphenyls (4). When present at hazardous waste sites, CF is often a focal point for evaluating the feasibility of bioremediation, since it is toxic to many obligate anaerobic prokaryotes (44). For example, 1 mg/liter of CF completely inhibited dechlorination of tetrachloroethene (PCE) by a chlororespiring anaerobic isolate (32). Inhibition of reductive dechlorination of chloroethenes by CF is a general problem for sites cocontaminated with CF, which can only be overcome by first removing the CF (6).In spite of major recent advances in bioremediation of chlorinated organic compounds, treatment of CF, especially at high concentrations (e.g., Ͼ100 mg/liter), remains challenging. Although aerobic biotransformation of CF is possible (e.g., cometabolism by a butane-grown strain) (14), CF is more difficult to cometabolize than trichloroethene (42). Biotransformation of CF by mixed or pure cultures under methanogenic (5, 21) and sulfate-reducing (20) conditions has been reported, however, only at low-mg/liter CF concentrations.Corrinoids such as vitamin B 12 (i.e., cyanocobalamin) are effective catalysts for increasing the rate of halomethane biotransformation under anaerobic conditions. Addition of vitamin B 12 also shifts the pathway away from reductive dechlorination and toward hydrolytic and substitutive reactions, forming CO, CO 2 , and organic acids as the major products (8,23,24). With low levels of B 12 added (3 to 5% molar ratios of CF), an enrichment culture grown on dichloromethane (DCM) as the sole substrate (8) and a lactate-grown sulfate-reducing enrichment culture (18) were able to biotransform up ...

show abstract

mentioning

confidence: 99%

Anaerobic Biotransformation of High Concentrations of Chloroform by an Enrichment Culture and Two Bacterial Isolates

Shan¹,

Kurtz

Mykytczuk

et al. 2010

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…Transformation of CT to CO 2 via HCOOH or CO are also energetically very favorable reactions with an overall G 0 of -619.7 kJ/reaction. Both biotic transformation of CT to HCOOH and CT transformation to CO have been demonstrated (Hashsham et al 1995, Dybas et al 1995, Stromeyer et al 1992. The mechanism of this conversion is not yet clear, but Egli et al (1988Egli et al ( , 1990 proposed that CT transformation may involve the acetyl-CoA pathway and that cobamides could play a role.…”

Section: Discussionmentioning

confidence: 99%

“…The mechanism of this conversion is not yet clear, but Egli et al (1988Egli et al ( , 1990 proposed that CT transformation may involve the acetyl-CoA pathway and that cobamides could play a role. There are several reports about the stimulation of CT transformation in the presence of cobamides (Chiu and Reinhard 1996, Hashsham et al 1995, Stromeyer et al 1992). It is not clear whether CT was degraded via HCOOH or CO in our reactor.…”

Section: Discussionmentioning

confidence: 99%

Untitled

Best¹,

Hunneman²,

Doddema³

et al. 1999

Biodegradation

View full text Add to dashboard Cite

“…The level of such DOC is approximately 1 mg/l in marine waters and is commonly less than 5 mg/l in oligotrophic fresh waters. Moreover, if significant decomposition of this organic matter were occurring, the concentration should fall at increasing distances away from the water's surface, where the organic matter is being generated photosynthetically by the phytoplankton [94,[225][226][227][228][229][230]. Because no such marked decline is evident with depth, it was hypothesized that biodegradation must be slow.…”

Section: Explanationsmentioning

confidence: 99%

“…Studies of the fate of PAHs have shown that their microbial mineralization, especially PAHs with four or more benzene rings, decreases with increasing contaminant residence time in soils [150,230,350]. Decreased microbial mineralization is often attributed to PAHs association with the soil organic matrix (SOM) [282,230].…”

Section: Bioavailabilitymentioning

confidence: 99%

Microbial Transformations at Aqueous-Solid Phase Interfaces: A Bioremediation Approach

Aboul-Kassim

Simoneit

The Handbook of Environmental Chemistry

View full text Add to dashboard Cite

Cobalamin-enhanced anaerobic biotransformation of carbon tetrachloride

Cited by 45 publications

References 31 publications

Anaerobic Biotransformation of High Concentrations of Chloroform by an Enrichment Culture and Two Bacterial Isolates

Anaerobic Biotransformation of High Concentrations of Chloroform by an Enrichment Culture and Two Bacterial Isolates

Untitled

Microbial Transformations at Aqueous-Solid Phase Interfaces: A Bioremediation Approach

Contact Info

Product

Resources

About