Chromate reduction by PVA-alginate immobilized Streptomyces griseus in a bioreactor

Poopal, Ashwini C.; Laxman, R. Seeta

doi:10.1007/s10529-008-9829-8

Cited by 23 publications

(5 citation statements)

References 19 publications

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“…Biologically available adsorbents, biosorbents, have proved to be a good alternative for the treatment of various toxic metal ions and Cr(VI), because of their low cost and significant uptake capacity. − Whether living or nonliving, their immobilization on the appropriate matrix surface leads to an enhancement of their adsorption capacity because of the improved physical and mechanical properties, for example, mechanical strength, larger pore volumes, and rigidity on the solid. − One of the suitable porous solid supports for the biosorbents is silica that has been used extensively for the removal of toxic metal ions. − Both living and nonliving materials are employed in the preparation of silica-based biosorbents for the removal of Cr(VI).…”

Section: Biologically Modified Silica Materialsmentioning

confidence: 99%

Recent Advances in Silica-Based Materials for the Removal of Hexavalent Chromium: A Review

2015

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Hexavalent chromium [Cr(VI)], one of the most toxic contaminants, is released in the environment due to various anthropogenic activities. Exposure of Cr(VI) can pose a serious threat to the public health as well as flora and fauna. Effective treatment of Cr(VI) is, therefore, very essential from safety, health, and environment points of view. The present review focuses on the development of silica-based materials for the adsorption of Cr(VI) from wastewater. After discussing toxicity issues and general removal methods of Cr(VI), the importance of silica materials are highlighted. The silica has different shapes, sizes, surface areas, and pore diameters and, hence, can play a vital role in designing the adsorbent. They can be modified into organic, inorganic, polymeric, biological, and ionic liquid based materials. Therefore, they are broadly classified into these five categories. The adsorption isotherms and kinetics of these materials for Cr(VI) are discussed and compared with each other. Future prospects based on the findings of the review article are summarized in the end which mainly emphasizes the importance of biosorbents and ionic liquid immobilized silica materials for the treatment of Cr(VI).

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Section: Biologically Modified Silica Materialsmentioning

confidence: 99%

Recent Advances in Silica-Based Materials for the Removal of Hexavalent Chromium: A Review

2015

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“…Sonication was the best method to release the chromate reductase expressed constitutively. The enzyme showed optimum activity at 28°C and pH 7 (Poopal and Laxman 2009a). Different matrices were tested for whole cell immobilization of this chromate-reducing organism and PVA-alginate was found to be the most effective and was used in a bioreactor.…”

Section: Bacterial Cr(vi) Resistancementioning

confidence: 99%

Remediation of chromium contaminants using bacteria

Kanmani¹,

Aravind²,

Preston

2011

Int. J. Environ. Sci. Technol.

125

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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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“…The capability to reduce Cr(VI) to Cr(III) was evidenced in both the bacterial strains isolated in this study. It is known that different bacterial strains were isolated from polluted sites, as a strain of Streptomyces griseus able to reduce Cr(VI) both in virtue of the activity of free cells and of the immobilized ones [111]. Autochthonous bacteria resistant to high levels of Cr(VI) were isolated from polluted sediments.…”

Section: Resultsmentioning

confidence: 99%

Microbial Reduction of Hexavalent Chromium as a Mechanism of Detoxification and Possible Bioremediation Applications

Focardi¹,

Pepi²,

Focardi³

2013

Biodegradation - Life of Science

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that Cr III is involved in the tertiary structure of proteins and in the conformation of cell RNA and DNA [ , ]. . . Toxicity of chromiumCr VI exposure in humans can induce allergies, irritations, eczema, ulceration, nasal and skin irritations, perforation of eardrum, respiratory track disorders and lung carcinoma [ , , ]. Moreover, Cr VI evidences the capability to accumulate in the placenta, damaging fetal development [ ]. Cr VI pollution in the environment alters the structure of soil microbial communities [ ], reducing microbial growth and related enzymatic activities, with a consequent persistence of organic matter in soils and accumulation of Cr VI [ ].The toxic action of Cr VI is due to its capability to easily penetrate cellular membranes, and cell membrane damages caused by oxidative stress induced by Cr VI have been extensively reported, both in eukaryotic and prokaryotic cells, with effects such as loss of membrane integrity or inhibition of the electron transport chain [ , ]. Moreover, Cr VI enters cells using the sulfate transport system of the membrane in cells of organisms that are able to use sulfate [ , , , , , ].Once Cr VI entered into cells, spontaneous reactions occur with the intracellular reductants as ascorbate and glutathione, generating the short-lived intermediates Cr V and/or Cr IV , free radicals and the end-product Cr III [ , , ]. In the cytoplasm, Cr V is oxidized to Cr VI and the process produces a reactive oxygen species, referred as ROS, that easily combines with DNA-protein complexes. On the other hand, Cr IV is able to bind to cellular materials, altering their normal physiological functions [ , ]. It is known that Cr VI species and hydroxyl radicals cause DNA lesions in vivo [ ]. The intermediates that originated from the action of Cr VI are dangerous to cell organelles, proteins and nucleic acids [ , , ]. Cr VI is a very dangerous chemical form on biological systems as it can induce mutagenic, carcinogenic and teratogenic effects. Moreover, Cr VI is able to induce oxidative stress in cells, damaging its DNA [ ]. Inside of cells, the Cr III -DNA adducts and related hydroxyl radical oxidative DNA damages have a central role in originating the genotoxic and mutagenic effects [ ]. Moreover, the formation of Cr III -DNA binary adducts and L-cysteine-Cr III -DNA and ascorbateCr III -DNA ternary adducts likely increase both genotoxicity and mutagenicity in human cells [ , ]. Again the formation of DNA protein cross-linking, a process favoured by Cr VI , induces a significant promutagenic effect [ ].Considering the dangerous effects Cr VI can cause to human health, Cr VI has been comprised among priority pollutants and listed as a class A human carcinogen by the US Environmental Protection Agency USEPA [ ].The cell membrane is nearly impermeable to Cr III , Cr III has thus only about one thousandth of the toxicity of Cr VI [ , ]. Taking into account these considerations, it is possible to conclude that, depending on its oxidation state, chromium can have different biological effects,...

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Chromate reduction by PVA-alginate immobilized Streptomyces griseus in a bioreactor

Cited by 23 publications

References 19 publications

Recent Advances in Silica-Based Materials for the Removal of Hexavalent Chromium: A Review

Recent Advances in Silica-Based Materials for the Removal of Hexavalent Chromium: A Review

Remediation of chromium contaminants using bacteria

Microbial Reduction of Hexavalent Chromium as a Mechanism of Detoxification and Possible Bioremediation Applications

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