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Biodegradation of the metallic carcinogen hexavalent chromium Cr(VI) by an indigenously isolated bacterial strain.

Das AP, Mishra S - J Carcinog (2010)

Bottom Line: At about 50 mg/L initial Cr(VI) concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation.The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei.Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI).

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre of Biotechnology, Siksha 'O' Anusandhan University, Bhubaneswar, India.

ABSTRACT

Background: Hexavalent chromium [Cr(VI)], a potential mutagen and carcinogen, is regularly introduced into the environment through diverse anthropogenic activities, including electroplating, leather tanning, and pigment manufacturing. Human exposure to this toxic metal ion not only causes potential human health hazards but also affects other life forms. The World Health Organization, the International Agency for Research on Cancer, and the Environmental Protection Agency have determined that Cr(VI) compounds are known human carcinogens. The Sukinda valley in Jajpur District, Orissa, is known for its deposit of chromite ore, producing nearly 98% of the chromite ore in India and one of the prime open cast chromite ore mines in the world (CES, Orissa Newsletter).

Materials and methods: Our investigation involved microbial remediation of Cr(VI) without producing any byproduct. Bacterial cultures tolerating high concentrations of Cr were isolated from the soil sample collected from the chromite-contaminated sites of Sukinda, and their bioaccumulation properties were investigated. Strains capable of growing at 250 mg/L Cr(VI) were considered as Cr resistant.

Results: The experimental investigation showed the maximum specific Cr uptake at pH 7 and temperature 30°C. At about 50 mg/L initial Cr(VI) concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation. The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei.

Conclusion: Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI).

No MeSH data available.


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Phylogenetic tree made in MEGA 3.1 software using neighbor joining method—optimum parameters for Cr(VI) bioreduction
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Figure 0003: Phylogenetic tree made in MEGA 3.1 software using neighbor joining method—optimum parameters for Cr(VI) bioreduction

Mentions: The isolates were tested for their chromate tolerance at different concentrations (20–200μL/mL) in solid agar medium. Three bacteria showed resistance to 100 mg/L of Cr(VI) in nutrient agar media among which Brevibacterium sp. was able to grow to a concentration of 250 mg/L of Cr(VI) as illustrated in Figure 3. Two isolated species, such as Arthrobacter sp. and a Bacillus sp., from tannery waste contaminated soil that showed similar resistance to Cr(VI) and had the ability to reduce Cr(VI) to Cr(III).[10] Both the bacterial strains tolerated for Cr(VI) at 100 mg/mL on a minimal salt agar medium supplemented with 0.5% glucose, but only Arthrobacter could grow in liquid medium at this concentration. Arthrobacter sp. could reduce Cr(VI) up to 50 μg/mL, whereas Bacillus sp. was not able to reduce Cr(VI) beyond 20 μg/mL. Arthrobacter sp. was distinctly superior to the Bacillus sp. in terms of their Cr(VI)-reducing ability and resistance to Cr(VI).


Biodegradation of the metallic carcinogen hexavalent chromium Cr(VI) by an indigenously isolated bacterial strain.

Das AP, Mishra S - J Carcinog (2010)

Phylogenetic tree made in MEGA 3.1 software using neighbor joining method—optimum parameters for Cr(VI) bioreduction
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2957624&req=5

Figure 0003: Phylogenetic tree made in MEGA 3.1 software using neighbor joining method—optimum parameters for Cr(VI) bioreduction
Mentions: The isolates were tested for their chromate tolerance at different concentrations (20–200μL/mL) in solid agar medium. Three bacteria showed resistance to 100 mg/L of Cr(VI) in nutrient agar media among which Brevibacterium sp. was able to grow to a concentration of 250 mg/L of Cr(VI) as illustrated in Figure 3. Two isolated species, such as Arthrobacter sp. and a Bacillus sp., from tannery waste contaminated soil that showed similar resistance to Cr(VI) and had the ability to reduce Cr(VI) to Cr(III).[10] Both the bacterial strains tolerated for Cr(VI) at 100 mg/mL on a minimal salt agar medium supplemented with 0.5% glucose, but only Arthrobacter could grow in liquid medium at this concentration. Arthrobacter sp. could reduce Cr(VI) up to 50 μg/mL, whereas Bacillus sp. was not able to reduce Cr(VI) beyond 20 μg/mL. Arthrobacter sp. was distinctly superior to the Bacillus sp. in terms of their Cr(VI)-reducing ability and resistance to Cr(VI).

Bottom Line: At about 50 mg/L initial Cr(VI) concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation.The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei.Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI).

View Article: PubMed Central - HTML - PubMed

Affiliation: Centre of Biotechnology, Siksha 'O' Anusandhan University, Bhubaneswar, India.

ABSTRACT

Background: Hexavalent chromium [Cr(VI)], a potential mutagen and carcinogen, is regularly introduced into the environment through diverse anthropogenic activities, including electroplating, leather tanning, and pigment manufacturing. Human exposure to this toxic metal ion not only causes potential human health hazards but also affects other life forms. The World Health Organization, the International Agency for Research on Cancer, and the Environmental Protection Agency have determined that Cr(VI) compounds are known human carcinogens. The Sukinda valley in Jajpur District, Orissa, is known for its deposit of chromite ore, producing nearly 98% of the chromite ore in India and one of the prime open cast chromite ore mines in the world (CES, Orissa Newsletter).

Materials and methods: Our investigation involved microbial remediation of Cr(VI) without producing any byproduct. Bacterial cultures tolerating high concentrations of Cr were isolated from the soil sample collected from the chromite-contaminated sites of Sukinda, and their bioaccumulation properties were investigated. Strains capable of growing at 250 mg/L Cr(VI) were considered as Cr resistant.

Results: The experimental investigation showed the maximum specific Cr uptake at pH 7 and temperature 30°C. At about 50 mg/L initial Cr(VI) concentrations, uptake of the selected potential strain exceeded 98% within 12 h of incubation. The bacterial isolate was identified by 16S rRNA sequencing as Brevebacterium casei.

Conclusion: Results indicated promising approach for microbial remediation of effluents containing elevated levels of Cr(VI).

No MeSH data available.


Related in: MedlinePlus