Studies on biological reduction of chromate by Streptomyces griseus

Poopal, Ashwini C.; Laxman, R. Seeta

doi:10.1016/j.jhazmat.2009.03.126

Cited by 60 publications

(39 citation statements)

References 27 publications

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“…Cr(VI) reduction efficiency decreased as Cr(VI) was increased from 2 to 12 mg/L but increased with an increase in biomass concentration. However, increasing the flow rate from 2 to 8 ml/h did not significantly affect Cr(VI) reduction (Poopal and Laxman 2009b). Such immobilized S. griseus cells could be applied for large-scale bioremediation of chromate-containing wastewaters.…”

Section: Bacterial Cr(vi) Resistancementioning

confidence: 96%

Remediation of chromium contaminants using bacteria

Kanmani¹,

Aravind²,

Preston

2011

Int. J. Environ. Sci. Technol.

123

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Chromium contaminants emanating from industrial activities pose a significant threat to human's wellbeing. Chromium (III) and Chromium (VI) are the forms in which they are commonly encountered, of which the trivalent form is relatively benign. Hence, biological reduction of hexavalent chromium has been widely explored by researchers, yielding fruitful outcomes, opening up exciting avenues and also throwing up new challenges. This article attempts to review this area of research. Microbes, especially bacteria capable of Chromium (VI) reduction, belonging to a heterogeneous group have been isolated from contaminated sites. They exhibit plasmid-mediated chromate resistance and the reduction is enzymatically mediated. Reduction studies have been carried out with free and immobilized enzymes as well as whole cells. Experiments have been carried out in specifically designed bioreactors operated in batch and continuous modes. Although significant progress has been made, much needs to be done for its successful in situ application as the organism may not withstand the Chromium concentration or may be impeded by the presence of other toxicants. With molecular engineering, it may be possible to derive strains with improved performance even under stressful field conditions.

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Section: Bacterial Cr(vi) Resistancementioning

confidence: 96%

Remediation of chromium contaminants using bacteria

Kanmani¹,

Aravind²,

Preston

2011

Int. J. Environ. Sci. Technol.

123

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“…Actinomycetes act as a major component of the microbial population in most of the soil. About 90% of the total actinomycetes population consists of Streptomyces species [4]. Soil actinomycetes can produce a wide range of secondary metabolites and about 70% of the naturally derived antibiotics that are currently in clinical use are produced by them [5].…”

Section: Introductionmentioning

confidence: 99%

Isolation and Characterization of Actinomycetes From Soil of Ad-Dawadmi, Saudi Arabia and Screening Their Antibacterial Activities

Sheik

Maqbul

Shankar

et al. 2017

Int J Pharm Pharm Sci

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Objective: To isolate and characterize novel actinomycetes and to evaluate their antibacterial activity against drug-resistant pathogenic bacteria Methods: In the present study, 19 soil samples were collected from different localities of Ad-Dawadmi, Saudi Arabia. Actinomycetes were isolated from these samples using serial dilution and plating method on Actinomycetes isolation agar supplemented with nalidixic acid and actidione to inhibit bacteria and fungi. Crude extracts of potential actinomycetes were produced by submerged fermentation. The antimicrobial activity of crude extracts of actinomycetes was tested against different bacteria using the agar well diffusion method. Characterization of the isolates was done by morphological, physiological and biochemical methods.Results: A total of 9 (47%) isolates of actinomycetes were isolated from 19 different soil samples tested. Among them, 4 (44%) isolates confirmed as Streptomyces sp. showed potential antimicrobial activity against one or more test organisms. Crude extracts were made from these 4 actinomycetes isolates(DOM1, DOM3, DP3, DP4)and tested for their antibacterial activities against 4 different clinical bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus). Crude extract from DP3 isolate showed highest antibacterial activity against all the four test organisms (28 mm, 21 mm, 20 mm and 18 mm) respectively and DP4 showed lowest antibacterial activity against all the four test organisms (14 mm, 12 mm, 0 mm, 6 mm) respectively. The highest zone of inhibition was shown by DP3 against Staphylococcus aureus (28 mm) and Escherichia coli was resistant for DP4. Most of the Inhibition zones produced by crude extracts showed significant differences when compared with control, tested against test organisms (P<0.05). Inhibition zones produced by DP3 and DOM1 against Staphylococcus aureus were 28 mm and 23 mm, respectively which were strong active when compared with control Ciprofloxacin (18 mm). Conclusion:Further studies for purification of bioactive metabolites and molecular characterization analysis of isolated Streptomyces sp. are in progress which would be helpful in discovering novel compounds of commercial value.

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“…The isolates were first grown at 28°C with shaking at 200 rpm in Nutrient Broth (NB) for 48h. Then a fixed amount of this vegetative inoculum (10% v/v) (Poopal and Laxman, 2009) was used to inoculate nutrient broth medium supplemented with appropriate amount (1-5 mM) of Cr(VI). The cultures were incubated at 28°C with shaking at 200 rpm.…”

Section: Screening Of Isolates For Chromium (Vi)mentioning

confidence: 99%

“…However, oxidized form of chromium [Cr(VI)] is extremely toxic and exhibits mutagenic, carcinogenic and teratogenic effects on biological systems (Poopal and Laxman, 2009). Cr(VI) is highly water soluble and more mobile, thus spreads easily beyond the site of initial contamination, while Cr(III) is relatively inert, less mobile, less bioavailable and easily adsorbed on mineral surfaces.…”

Section: Introductionmentioning

confidence: 99%

Antibiotic Resistance and Chromium Reduction Pattern Among Actinomycetes

Ali¹

2012

American Journal of Biochemistry and Biotechnology

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Actinomycetes, one of the most important groups of microbes, exhibit many interesting activities such as degradation and transformation of organic and metal substrates together with production of antibiotics. With these bioactivities, actinomycetes would play an important role in the webs of the marine environment. The present study was designed to evaluate the antibiotic resistance pattern, antibiotic producing potential and chromium resistance as well as chromium reduction potential of a range of actinomycetes isolated from marine environments. Actinomycetes were isolated from marine sediment samples obtained from St. Martin's Island in Bangladesh. Antibiotic resistance among the selected isolates was studied against 10 different antibiotics by disc diffusion method and antibiotic producing potential was assessed by the perpendicular streak method. The isolates were screened for resistance towards heavy metal Cr(VI) on culture plates supplemented with Cr(VI) at concentrations ranging from 1-5 mM of Cr(VI). Highly resistant isolates were subjected to screening for Cr(VI) reduction activity, which was estimated using the Cr(VI) specific colorimetric reagent 1, 5-diphenylcarbazide. Out of the total 30 different selected isolates, 25 (83.33%) showed resistance against more than three antibiotics and 6 (20%) showed resistance to more than six antibiotics. Ninety three percent of the isolates showed MAR index greater than 0.2 and tolerance to Cr(VI) at 1mM of initial Cr(VI). None of the isolates displayed antimicrobial activity against the organisms tested. Among the isolates tested for chromate reduction, two were most efficient showing complete reduction of 1mM Cr(VI) within 24 h. These two isolates were capable of reducing chromate even at high initial Cr(VI) concentrations. Remarkably, the isolate SM-11 was found to reduce 82.67%, 44.34% of Cr(VI) at 2.5mM, 5mM of initial Cr(VI) concentrations respectively, within 72h of incubation. The majority of the actinomycetes isolates displayed resistance to both antibiotics and heavy metal chromium which indicates the possible acquisition of resistance factors due to environmental or human activities. The study also demonstrates possible correlation between antibiotic resistance and metal tolerance. Two of the isolates which showed considerable chromium reduction activity even at high chromium concentrations, may find potential application in bioremediation approaches.

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Studies on biological reduction of chromate by Streptomyces griseus

Cited by 60 publications

References 27 publications

Remediation of chromium contaminants using bacteria

Remediation of chromium contaminants using bacteria

Isolation and Characterization of Actinomycetes From Soil of Ad-Dawadmi, Saudi Arabia and Screening Their Antibacterial Activities

Antibiotic Resistance and Chromium Reduction Pattern Among Actinomycetes

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