Interrelations of the yeast Candida utilis and Cr(VI): metal reduction and its distribution in the cell and medium

Muter, Olga; Patmalnieks, Aloizijs; Rapoport, Alexander

doi:10.1016/s0032-9592(01)00136-4

Cited by 70 publications

(48 citation statements)

References 20 publications

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“…1997) and yeasts (Muter et al 2001;Ramirez-Ramirez et al 2004). One such study was the Cr(VI) reduction by Trichoderma viride in stirred tank and concentric tube airlift bioreactors.…”

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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“…1997) and yeasts (Muter et al 2001;Ramirez-Ramirez et al 2004). One such study was the Cr(VI) reduction by Trichoderma viride in stirred tank and concentric tube airlift bioreactors.…”

Section: Bacterial Cr(vi) Resistancementioning

confidence: 99%

Remediation of chromium contaminants using bacteria

Kanmani¹,

Aravind²,

Preston

2011

Int. J. Environ. Sci. Technol.

125

View full text Add to dashboard Cite

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“…NADH-dependent chromate reductase was found in a chromate-resistant strain of Candida maltosa [19]. Chromate reduction and distribution of the metal in the cells and medium was studied for the yeast Candida utilis [20].…”

Section: Introductionmentioning

confidence: 99%

Extra-cellular chromate-reducing activity of the yeast cultures

et al. 2006

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This paper reports on the experimental data supporting an essential role of extracellular reduction in chromate detoxification by baker's and non-conventional yeasts. A decrease of chromate content in the yeast culture coincides with an increase of Cr(III) content in extracellular liquid. At these conditions, cell-bound chromium level was insignificant and a dominant part of extra-cellular Cr(III) species was detected in the reaction with chromazurol S only after mineralization of the cell-free samples. This phenomenon of chromium "disappearance" can be explained by the formation of Cr(III) stable complexes with extra-cellular yeast-secreted components which are "inaccessible" in the reaction with chromazurol S without mineralization. It was shown that increasing sucrose concentration in a growth medium resulted in an increase of chromate reduction. A strong inhibition of chromate reduction by 0.25 mM sodium azide, a respiration inhibitor and a protonophore, testifies that extra-cellular chromate detoxification depends on energetic status of the yeast cells. It was shown that Cr(III)-biochelates produced in extra-cellular medium are of a different chemical nature and can be separated into at least two components by ion-exchange chromatography on anionit Dowex 1x10. A total yield of the isolated Cr(III)-biocomplexes is approximately 65 % (from initial level of chromate) with a relative molar ratio 8:5.

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“…Cr (VI) reducing capability has been described in some reports in the literature (Smith et. al., 2002;Sahin and A. Öztürk, 2005;Muter et. al., 2001;Ramírez-Ramírez et.…”

Section: Time Course Of Cr (Vi) Decrease and Cr (Iii) Productionmentioning

confidence: 99%