Hexavalent chromium reduction by whole cells and cell free extract of the moderate halophilic bacterial strain Halomonas sp. TA-04

Focardi, S.; Pepi, Milva; Landi, Giulia; Gasperini, Simone; Ruta, Marcella; Biasio, Pamela Di; Focardi, Silvano

doi:10.1016/j.ibiod.2011.11.003

Cited by 83 publications

(31 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Figure 6 also shows that chromate reductase activity was increased with supplementation of glucose or NADH. It has been reported that NADH and NADPH serve as electron donors and promote bacterial Cr(VI) reduction (Focardi et al 2012;Sau et al 2010). …”

Section: Cr(vi) Reduction By Cfementioning

confidence: 99%

“…Some microorganisms, mainly including the sulfate-reducing bacteria and dissimilatory Fe(III)-reducing strains, reduce Cr(VI) to Cr(III) indirectly by byproducts such as S(II) (Cheung and Gu 2003;Pagnanelli et al 2012) and Fe(II) ( Xu et al 2005;Cummings et al 2007). Most of reported Cr(VI)-reducing strains directly enzymatically reduce Cr(VI) to Cr(III) (Camargo et al 2003;Thacker et al 2007;Mistry et al 2010;Chen et al 2012;Focardi et al 2012). Chromate reductase activity is associated with the soluble cell fraction (Pal et al 2005;Sultan and Hasnain 2012) or membrane cell fraction (Wang et al 1990;Mangaiyarkarasi et al 2011).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Bioreduction of Chromate by an Isolated Bacillus anthracis Cr-4 with Soluble Cr(III) Product

Jian

Liu

et al. 2015

Water Air Soil Pollut

View full text Add to dashboard Cite

Microbial Cr(VI) reduction is a significant process in detoxification of Cr(VI) pollution. In this study, a new Cr(VI)-reducing bacterial strain, Cr-4, was isolated from soil around the chromiumcontaining slag. The analysis of the 16S ribosomal RNA (rRNA) gene sequence revealed that the newly isolated strain was closely related to Bacillus anthracis. The response to Cr(VI) stress and reduction capacity of the isolate were investigated. Cell growth decreased with the increase of Cr(VI) concentration. Cell morphology varied and cell growth was inhibited remarkably in the presence of 125 mg/L Cr(VI). The strain grew well and removed Cr(VI) effectively at a Cr(VI) concentration lower than 50 mg/L. Cr(VI)-reducing activity was inhibited by Zn 2+ , while significantly stimulated by Cu 2+ . The activity of Cr(VI) reduction by cell-free extract was demonstrated. Total chromium analysis and the energy-dispersive X-ray analysis (EDAX) spectrum revealed that Cr(VI) removal was caused mainly by microbial reduction rather than by biosorption and the main part of the reduced Cr(III) existed as soluble form in solutions.

show abstract

Section: Cr(vi) Reduction By Cfementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bioreduction of Chromate by an Isolated Bacillus anthracis Cr-4 with Soluble Cr(III) Product

Jian

Liu

et al. 2015

Water Air Soil Pollut

View full text Add to dashboard Cite

show abstract

“…[27] ; pH 6.3 for Thermus scotoductus SA-01 [21] ; pH 6.5 for Halomonas sp. TA-04 [28] ; and pH 8.6 for Pseudomonas ambigua G-1. [14] The optimum pH for chromate reductase correlates well with optimal growth pH for Cr-B4, which was found to be 8.4.…”

Section: Effect Of Phmentioning

confidence: 99%

Partial Purification and Characterization of Chromate Reductase of a NovelOchrobactrumsp. Strain Cr-B4

Hora

Shetty

2014

Preparative Biochemistry and Biotechnology

View full text Add to dashboard Cite

Hexavalent chromium contamination is a serious problem due to its high toxicity and carcinogenic effects on the biological systems. The enzymatic reduction of toxic Cr(VI) to the less toxic Cr(III) is an efficient technology for detoxification of Cr(VI)-contaminated industrial effluents. In this regard, a chromate reductase enzyme from a novel Ochrobactrum sp. strain Cr-B4, having the ability to detoxify Cr(VI) contaminated sites, has been partially purified and characterized. The molecular mass of this chromate reductase was found to be 31.53 kD, with a specific activity 14.26 U/mg without any addition of electron donors. The temperature and pH optima for chromate reductase activity were 40°C and 8.0, respectively. The activation energy (Ea) for the chromate reductase was found to be 34.7 kJ/mol up to 40°C and the activation energy for its deactivation (Ed) was found to be 79.6 kJ/mol over a temperature range of 50-80°C. The frequency factor for activation of chromate reductase was found to be 566.79 s(-1), and for deactivation of chromate reductase it was found to be 265.66 × 10(3) s(-1). The reductase activity of this enzyme was affected by the presence of various heavy metals and complexing agents, some of which (ethylenediamine tetraacetic acid [EDTA], mercaptoethanol, NaN3, Pb(2+), Ni(2+), Zn(2+), and Cd(2+)) inhibited the enzyme activity, while metals like Cu(2+) and Fe(3+) significantly enhanced the reductase activity. The enzyme followed Michaelis-Menten kinetics with Km of 104.29 µM and a Vmax of 4.64 µM/min/mg.

show abstract

“…Focardi et al. also reported the optimum pH of Cr(VI) reduction at 6.5, but other studies indicated pH optima of 6 , , and . This phenomenon suggested that pH has a significant influence on various level in different cultures.…”

Section: Resultsmentioning

confidence: 95%

“…Compared with the conventional physical and chemical treatment processes, microbial Cr(VI) reduction has been considered an economical, effective, and safe method that can reduce relatively lower concentrations of Cr(VI). A wide range of bacteria, such as Halomonas , Halomonas aquamarina , Bacillus subtilis , Lysinibacillus fusiformis , Bacillus cereus , Staphylococcus aureus , Ochrobactrum , and Hypocrea tawa , are reported to be able to reduce Cr(VI) to Cr(III). However, these reduction processes generally take several days or even weeks in practice, so isolating high‐efficiency bacteria of Cr(VI) reduction has become a topic of focus.…”

Section: Introductionmentioning

confidence: 99%

Isolation and Cr(VI) reduction characteristics of quinone respiration in Mangrovibacter plantisponsor strain CR1

Lian

et al. 2015

Biotech and App Biochem

View full text Add to dashboard Cite

A Cr(VI)-reducing Mangrovibacter plantisponsor strain, CR1, was isolated from tannery effluent sludge and had quinone respiration characteristics. Its chromate (CrO4 (2-) ) resistance, quinone respiration characteristics, and Cr(VI) reduction efficiencies were evaluated in detail. Strain CR1 exhibited a high Cr(VI) resistance with a minimal inhibitory concentration (MIC) of 32 mM in LB medium, and its quinone respiration could occur when an electron donor and strain CR1 both existed in the reaction system. Cr(VI) reduction by strain CR1 was significantly enhanced by a factor of 0.4-4.3 with five different quinone compounds: anthraquinone-2,7-disulfonate, anthraquinone-1-sulfonate, anthraquinone-2-sulfonate (AQS), anthraquinone-2,6-disulfonate, and anthraquinone-1,5-disulfonate. AQS was the best electron shuttle among them, and the greatest enhancement to the Cr(VI) bio-reduction was achieved with 0.96 mM AQS. The correlation between the reaction constant k (mg Cr(VI) g(-1) dry cell weight H(-1) ) and thermodynamic temperature T (K) was expressed as an Arrhenius equation lnk=-7662.9/T+27.931(R2=0.9486); the activation energy Ea was 63.71 kJ mol(-1) , and the pre-exponential factor A was 1.35 × 10(12) mg Cr(VI) g(-1) dry cell weight H(-1) . During the Cr(VI) reduction process, the pH tended to become neutral, and the oxidation-reduction potential decreased to -440 mV. The efficient reduction of Cr(VI) mediated by a quinone respiration strain shows potential for the rapid anaerobic removal of Cr(VI).

show abstract

Hexavalent chromium reduction by whole cells and cell free extract of the moderate halophilic bacterial strain Halomonas sp. TA-04

Cited by 83 publications

References 42 publications

Bioreduction of Chromate by an Isolated Bacillus anthracis Cr-4 with Soluble Cr(III) Product

Bioreduction of Chromate by an Isolated Bacillus anthracis Cr-4 with Soluble Cr(III) Product

Partial Purification and Characterization of Chromate Reductase of a NovelOchrobactrumsp. Strain Cr-B4

Isolation and Cr(VI) reduction characteristics of quinone respiration in Mangrovibacter plantisponsor strain CR1

Contact Info

Product

Resources

About