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1.
Heavy-metal chromium [Cr(VI)] is a ubiquitous environmental pollutant. Comparing with chemical reduction, microbiological
reduction is considered to be a friendly and cheaper way to decrease the damage caused by chromate. A bacterial strain, CR-07,
which is resistant to and capable of reducing chromate was isolated from a mud sample of iron ore and identified as a Microbacterium sp. The bacterium had a high degree of tolerance to chromate, and could grow in LB medium containing 4.08 mM of K 2Cr 2O 7. It also had a degree of resistance to other heavy metals, e.g. Cd 2+, Pb 2+, Zn 2+, Cu 2+, Co 2+, Hg 2+ and Ag +. The bacterium could remove 1.02 mM of Cr(VI) from LB medium within 36 h of incubation. Chromate removal was achieved in
the supernatant from the bacterial cultures, and corresponded to chromate reduction. The activity of chromate reduction by
the bacterium was not related to enzymes or reducing sugars, while fluorometric assay suggested that glutathione, a chromate-reducing
substance which was produced by the bacterium, was one of the factors that contributed to the reduction of Cr(VI). 相似文献
2.
The purpose of the present study was to investigate the in vitro and the in vivo effects of cadmium, zinc, mercury and lead on -aminolevulinic acid dehydratase (ALA-D) activity from radish leaves. The in vivo effect of these metals on growth, DNA and protein content was also evaluated. The results demonstrated that among the elements studied Cd 2+ presented the highest toxicity for radish. 50% inhibition of ALA-D activity (IC 50) in vitro was at 0.39, 2.39, 2.29, and 1.38 mM Cd 2+, Zn 2+, Hg 2+ and Pb 2+, respectively. After in vivo exposure Cd 2+, Zn 2+, Hg 2+ and Pb 2+ inhibited ALA-D by about 40, 26, 34 and 15%, respectively. Growth was inhibited by about 40, 10, 25, and 5% by Cd 2+, Zn 2+, Hg 2+, and Pb 2+, respectively. DNA content was reduced about 35, 30, 20, and 10% for Cd 2+, Zn 2+, Hg 2+, and Pb 2+, respectively. The metal concentration in radish leaves exposed to Cd 2+, Zn 2+, Hg 2+, and Pb 2+ was 18, 13, 6, and 7 mol g –1, respectively. The marked ability of radish to accumulate Cd 2+ and Zn 2+ raises the possibility of using this vegetable as a biomonitor of environmental contamination by these metals. 相似文献
3.
Bacillus species producing a thermostable phytase was isolated from soil, boiled rice, and mezu (Korean traditinal koji). The activity of phytase increased markedly at the late stationary phase. An extracellular phytase from Bacillus sp. KHU-10 was purified to homogeneity by acetone precipitation and DEAE-Sepharose and phenyl-Sepharose column chromatographies. Its molecular weight was estimated to be 46 kDa on gel filtration and 44 kDa on SDS-polyacrylamide gel elctrophoresis. Its optimum pH and temperature for phytase activity were pH 6.5-8.5 and 40°C without 10 mM CaCl 2 and pH 6.0-9.5 and 60°C with 10 mM CaCl 2. About 50% of its original activity remained after incubation at 80°C or 10 min in the presence of 10 mM CaCl 2. The enzyme activity was fairly stable from pH 6.5 to 10.0. The enzyme had an isoelectric point of 6.8. As for substrate specificity, it was very specific for sodium phytate and showed no activity on other phosphate esters. The K
m value for sodium phytate was 50 M. Its activity was inhibited by EDTA and metal ions such as Ba 2+, Cd 2+, Co 2+, Cr 3+, Cu 2+, Hg 2+, and Mn 2+ ions. 相似文献
4.
The effects of fourteen metal ions (As 3+, As 5+, Cd 2+, Co 2+, Cr 3+, Cr 6+, Hg 2+, Li +, Mg 2+, Mn 2+, Ni 2+, Se 4+, V 5+, VO 2+) on the proliferation and differentiation in mouse B16 melanoma cells cultivated in vitro were analyzed. Cell number assays,
melanin, and protein measurements, a 3(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide reduction test (MTT survival
test), and a clonal growth assay were performed. At 10 −4
M, metal ions such as As 3+, As 5+, Cd 2+, Cr 6+, Se 4+, V 5+, VO 2+, and, to a minor extent, Li +, Hg 2+, and Co 2+ significantly reduced the number of the B16 melanoma cells. For the same molar concentration, the order of the levels of
cell toxicity of the metal compounds to B16 cells as measured by the MTT test was as follows: Hg 2+>Cr 6+=Cd 2+>As 3+, As 5+>V 5+, VO 2+>Se 4+=Ni 2+=Co 2+=Li +. An increased synthesis of melanin in B16 cells was noted after incubation with Co 2+, Ni 2+, Cd 2+, and Li +, whereas Se 4+ had, on the contrary, an inhibiting effect on melanogenesis. 相似文献
5.
A water‐soluble, high‐output fluorescent sensor, based on a lumazine ligand with a thiophene substituent for Cd 2+, Hg 2+ and Ag + metal ions, is reported. The sensor displays fluorescence enhancement upon Cd 2+ binding (log β = 2.79 ± 0.08) and fluorescence quenching by chelating with Ag + and Hg 2+ (log β = 4.31 ± 0.15 and 5.42 ± 0.1, respectively). The mechanism of quenching is static and occurs by formation of a ground‐state non‐fluorescent complex followed by rapid intersystem crossing. The value of the Stern–Volmer quenching rate constant ( kq) by Ag + ions is close to 6.71 × 10 12 mol/L/s at 298 K. The thermodynamic parameters ( ΔG, ΔH and ΔS) were also evaluated and indicated that the complexation process is spontaneous, exothermic and entropically favourable. The quantitative linear relationship between the softness values of Klopman ( σK) or Ahrland ( σA) and the experimental binding constants ( β) being in the order of Hg 2+ > Ag + > Cd 2+ suggests that soft–soft interactions are the key for the observed sensitivity and selectivity in the presence of other metal ions, such as: Pb 2+, Ni 2+, Mn 2+, Cu 2+, Co 2+, Zn 2+ and Mg 2+ ions. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
Abscisic acid (ABA), a widely known phytohormone involved in the plant response to abiotic stress, plays a vital role in mitigating Cd2+ toxicity in herbaceous species. However, the role of ABA in ameliorating Cd2+ toxicity in woody species is largely unknown. In the present study, we investigated ABA restriction on Cd2+ uptake and the relevance to Cd2+ stress alleviation in Cd2+-hypersensitive Populus euphratica. ABA (5 μM) markedly improved cell viability and growth but reduced membrane permeability in CdCl2 (100 μM)-stressed P. euphratica cells. Moreover, ABA significantly increased the activity of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX), contributing to the scavenging of Cd2+-elicited H2O2 within P. euphratica cells during the period of CdCl2 exposure (100 μM, 24–72 h). ABA alleviation of Cd2+ toxicity was mainly the result of ABA restriction of Cd2+ uptake under Cd2+ stress. Steady-state and transient flux recordings showed that ABA inhibited Cd2+ entry into Cd2+-shocked (100 μM, 30 min) and short-term-stressed P. euphratica cells (100 μM, 24–72 h). Non-invasive micro-test technique data showed that H2O2 (3 mM) stimulated the Cd2+-elicited Cd2+ influx but that the plasma membrane (PM) Ca2+ channel inhibitor LaCl3 blocked it, suggesting that the Cd2+ influx was through PM Ca2+-permeable channels. These results suggested that ABA up-regulated antioxidant enzyme activity in Cd2+-stressed P. euphratica and that these enzymes scavenged the Cd2+-elicited H2O2 within cells. The entry of Cd2+ through the H2O2-mediated Ca2+-permeable channels was subsequently restricted; thus, Cd2+ buildup and toxicity were reduced in the Cd2+-hypersensitive species, P. euphratica. 相似文献
7.
The heavy metal resistant ciliate, Stylonychia mytilus, isolated from industrial wastewater has been shown to be potential bioremediator of contaminated wastewater. The ciliate
showed tolerance against Zn 2+ (30 μg/mL), Hg 2+ (16 μg/mL) and Ni 2+ (16 μg/mL). The metal ions slowed down the growth of the ciliate as compared with the culture grown without metal stress.
The reduction in cell population was 46% for Cd 2+, 38% for Hg 2+, 23% for Zn 2+, 39% for Cu 2+ and 51% for Ni 2+ after 8 days of metal stress. S. mytilus reduced 91% of Cd 2+, 90% of Hg 2+ and 98% of Zn 2+ from the medium after 96 h of incubation in a culture medium containing 10 μg/mL of the respective metal ions. Besides this,
the ciliate could also remove 88% of Cu 2+ and 73% Ni 2+ from the medium containing 5 μg/mL of each metal after 96 h. The ability of Stylonychia to take up variety of heavy metals from the medium could be exploited for metal detoxification and environmental clean-up
operations. 相似文献
8.
To determine the onset of the Cd 2+-hyperaccumulating phenotype in Euglena gracilis, induced by Hg 2+ pretreatment (Avilés et al. in Arch Microbiol 180:1–10, 2003), the changes in cellular growth, Cd 2+ uptake, and intracellular contents of sulfide, cysteine, γ-glutamylcysteine, glutathione and phytochelatins during the progress
of the culture were analyzed. In cells exposed to 0.2 mM CdCl 2, the Cd 2+-hyperaccumulating phenotype was apparent only after 48 h of culture, as indicated by the significant increase in cell growth
and higher internal contents of sulfide and thiol-compounds, along with a higher γ-glutamylcysteine synthetase activity. However,
the stiochiometry of thiol-compounds/Cd 2+ accumulated was similar for both control and Hg 2+-pretreated cells. Moreover, the value for this ratio was 2.1 or lower after 48-h culture, which does not suffice to fully
inactivate Cd 2+. It is concluded that, although the glutathione and phytochelatin synthesis pathway is involved in the development of the
Cd 2+-hyperaccumulating phenotype in E. gracilis, apparently other pathways and sub-cellular mechanisms are also involved. These may be an increase in other Cd 2+ chelating molecules such as di- and tricarboxylic acids, phosphate and polyphosphates, as well as Cd 2+ compartmentation into organelles.
César Avilés: In memoriam. 相似文献
9.
Summary The alga, Distigma proteus, isolated from industrial wastewater showed tolerance against Cd 2+ (8.0 μg/ml), Cr 6+ (12 μg/ml), Pb 2+ (15 μg/ml) and Cu 2+ (10 μg/ml). The metal ions slowed down the growth of the organism after 4–5 days of exposure. The reduction in cell population
was 90% for Cu 2+, 84% for Cd 2+, 71% for Cr 6+, and 63% for Pb 2+ after 8 days of metal stress. The order of resistance to heavy metal, in terms of reduction in the cellular population, was
Cu 2+ > Cd 2+ > Cr 6+ > Pb 2+. Chromium- and cadmium-processing capabilities of the alga were worked out for its potential use as a bioremediator of wastewater.
The reduction in the amount of Cr 6+ after 2, 4, 6 and 8 days of algal culture containing 5.0 μg Cr 6+ ml −1 of culture medium was 77, 85, 92 and 97%, respectively. Distigma could also remove 48% Cd 2+after 2 days, 68% after 4 days, 80% after 6 days and 90% after 8 days from the medium. The heavy metal uptake ability of Distigma can be exploited for metal detoxification and environmental clean-up operations. 相似文献
10.
The chromate resistant Gram-positive Bacillus cereus strain b-525k was isolated from tannery effluents, demonstrating optimal propagation at 37 °C and pH 8. The minimum inhibitory concentration (MIC) test showed that B. cereus b-525k can tolerate up to 32 mM Cr 6+, and also exhibit the ability to resist other toxic metal ions including Pb 2+ (23 mM), As 3+ (21 mM), Zn 2+ (17 mM), Cd 2+ (5 mM), Cu 2+ (2 mM), and Ni 2+ (3 mM) with the resistance order as Cr 6+ > Pb 2+ > As 3+ >Zn 2+ >Cd 2+ >Ni 2+ >Cu 2+. B. cereus b-525k showed maximum biosorption efficiency ( q) of 51 mM Cr 6+/g after 6 days. Chromate stress elicited pronounced production of antioxidant enzymes such as catalase (CAT) 191%, glutathione transferase (GST) 192%, superoxide dismutase (SOD) 161%, peroxidase (POX) 199%, and ascorbate peroxidase (APOX) (154%). Within B. cereus b-525k, the influence of Cr 6+ stress (2 mM) did stimulate rise in levels of GSH (907%) and non-protein thiols (541%) was measured as compared to the control (without any Cr 6+ stress) which markedly nullifies Cr 6+ generated oxidative stress. The pilot scale experiments utilizing original tannery effluent showed that B. cereus b-525k could remove 99% Cr 6+ in 6 days, thus, it could be a potential candidate to reclaim the chromate contaminated sites. 相似文献
11.
Living organisms are subject to stress, and among these stressors, heavy metals exposure triggers accumulation of sulfur metabolites.
Among these metabolites, glutathione and phytochelatins are found in several organisms, such as Euglena gracilis. Pre-exposing E. gracilis to low concentrations of Hg 2+ generates a population with resistance to even 0.2 mM Cd 2+, and this resistance relies partly on phytochelatins. p38 MAPK is stimulated by stress and is involved in apoptotic as well
as survival mechanisms. In this study, we explored its participation in heavy metal-induced stress and its possible role in
sulfur metabolite accumulation. We found that about 51% of the E. gracilis pretreated with Hg 2+ becomes resistant to Cd 2+ and proliferates despite the presence of this metal. The accumulation of the sulfur metabolites γ-glu-cys, glutathione and
phytochelatin 2 displayed cyclic patterns that were disturbed by a challenge with Cd 2+. We observed a p38 MAPK-like activity that was stimulated by acute or chronic heavy metal exposure, and its inhibition by
SB203580 slightly diminished the accumulation of sulfur compounds. p38 MAPK inhibition also affected basal levels of glutathione
in either pretreated or control cells. Thus, it appears that p38 MAPK mediates redox stress component of the signal pathway
induced by heavy metals. 相似文献
12.
Seed is a developmental stage that is highly protective against external stresses in the plant life cycle. In this study, we analyzed toxicity of essential (Cu 2+ and Zn 2+) and non-essential heavy metals (Hg 2+, Pb 2+ and Cd 2+) on seed germination and seedling growth in the model species Arabidopsis. Our results show that seedling growth is more sensitive to heavy metals (Hg 2+, Pb 2+, Cu 2+ and Zn 2+) in comparison to seed germination, while Cd 2+ is the exception that inhibited both of these processes at similar concentrations. To examine if toxicity of heavy metals is altered developmentally during germination, we incubated seeds with Hg 2+ or Cd 2+ only for a restricted period during germination. Hg 2+ displayed relatively strong toxicity at period II (12–24 h after imbibition), while Cd 2+ was more effective to inhibit germination at period I (0–12 h after imbibition) rather than at period II. The observed differences are likely to be due in part to selective uptake of different ions by the intact seed, because isolated embryos (without seed coat and endosperm) are more sensitive to both Hg 2+ and Cd 2+ at period I. We assessed interactive toxicity between heavy metals and non-toxic cations, and found that Ca 2+ was able to partially restore the inhibition of seedling growth by Pb 2+ and Zn 2+. 相似文献
13.
In the present investigation, five novel Cr(VI) reducing bacteria were isolated from tannery effluents and solid wastes and identified as Kosakonia cowanii MKPF2, Klebsiella pneumonia MKPF5, Acinetobacter gerneri MKPF7, Klebsiella variicola MKPF8 and Serratia marcescens MKPF12 by 16S rDNA gene sequence analysis. The maximum tolerance concentration of Cr(VI) as K 2Cr 2O 7 of the bacterial isolates was varying up to 2000 mg/L. Among the investigated bacterial isolates, A. gerneri MKPF7 was best in terms of reduction rate. The optimum temperatures for growth and Cr(VI) reduction by the bacterial isolates were 35 and 40 °C, respectively except A. gerneri MKPF7 which grew and reduced Cr(VI) optimally at 40 °C. The optimum pH for growth and Cr(VI) reduction by K. cowanii MKPF2, A. gerneri MKPF7 and S. marcescens MKPF12 was 7.0 whereas the optimum pH for growth and Cr(VI) reduction by K. pneumoniae MKPF5 and K. variicola MKPF8 were 7.0, 8.0 and 6.0, 7.0, respectively. All the bacterial isolates showed maximum tolerance against Ni 2+ and Zn 2+ whereas minimum tolerance was observed against Hg 2+ and Cd 2+. The bacteria isolated in the present study thus can be used as eco-friendly biological expedients for the remediation and detoxification of Cr(VI) from the contaminated environments. 相似文献
14.
Background Klebsiella variicola was very recently described as a new bacterial species and is very closely related to Klebsiella pneumoniae; in fact, K. variicola isolates were first identified as K. pneumoniae. Therefore, it might be the case that some isolates, which were initially classified as K. pneumoniae, are actually K. variicola. The aim of this study was to devise a multiplex-PCR probe that can differentiate isolates from these sister species.ResultThis work describes the development of a multiplex-PCR method to identify K. variicola. This development was based on sequencing a K. variicola clinical isolate (801) and comparing it to other K. variicola and K. pneumoniae genomes. The phylogenetic analysis showed that K. variicola isolates form a monophyletic group that is well differentiated from K. pneumoniae. Notably, the isolate K. pneumoniae 342 and K. pneumoniae KP5-1 might have been misclassified because in our analysis, both clustered with K. variicola isolates rather than with K. pneumoniae. The multiplex-PCR (M-PCR-1 to 3) probe system could identify K. variicola with high accuracy using the shared unique genes of K. variicola and K. pneumoniae genomes, respectively. M-PCR-1 was used to assay a collection of multidrug-resistant (503) and antimicrobial-sensitive (557) K. pneumoniae clinical isolates. We found K. variicola with a prevalence of 2.1% (23/1,060), of them a 56.5% (13/23) of the isolates were multidrug resistant, and 43.5% (10/23) of the isolates were antimicrobial sensitive. The phylogenetic analysis of rpoB of K. variicola-positive isolates identified by multiplex-PCR support the correct identification and differentiation of K. variicola from K. pneumoniae clinical isolates.ConclusionsThis multiplex-PCR provides the means to reliably identify and genotype K. variicola. This tool could be very helpful for clinical, epidemiological, and population genetics studies of this species. A low but significant prevalence of K. variicola isolates was found, implying that misclassification had occurred previously. We believe that our multiplex-PCR assay could be of paramount importance to understand the population dynamics of K. variicola in both clinical and environmental settings. 相似文献
15.
Complexes formed by reduced glutathione (GSH) with metal cations (Cr 2+, Mn 2+,Fe 2+,Co 2+,Ni 2+,Cu 2+,Zn 2+,Cd 2+,Hg 2+) were systematically investigated by the density functional theory (DFT). The results showed that the interactions of the metal cations with GSH resulted in nine different stable complexes and many factors had an effect on the binding energy. Generally, for the same period of metal ions, the binding energies ranked in the order of Cu 2+>Ni 2+>Co 2+>Fe 2+>Cr 2+>Zn 2+>Mn 2+; and for the same group of metal ions, the general trend of binding energies was Zn 2+>Hg 2+>Cd 2+. Moreover, the amounts of charge transferred from S or N to transition metal cations are greater than that of O atoms. For Fe 2+,Co 2+,Ni 2+,Cu 2+,Zn 2+,Cd 2+ and Hg 2+ complexes, the values of the Wiberg bond indices (WBIs) of M-S (M denotes metal cations) were larger than that of M-N and M-O; for Cr 2+ complexes, most of the WBIs of M-O in complexes were higher than that of M-S and M-N. Furthermore, the changes in the electron configuration of the metal cations before and after chelate reaction revealed that Cu 2+, Ni 2+,Co 2+ and Hg 2+ had obvious tendencies to be reduced to Cu +,Ni +,Co + and Hg + during the coordination process. 相似文献
17.
An alkaline protease from marine Engyodontium album was characterized for its physicochemical properties towards evaluation of its suitability for potential industrial applications.
Molecular mass of the enzyme by matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) analysis was calculated
as 28.6 kDa. Isoelectric focusing yielded pI of 3–4. Enzyme inhibition by phenylmethylsulfonyl fluoride (PMSF) and aprotinin
confirmed the serine protease nature of the enzyme. K
m, V
max, and K
cat of the enzyme were 4.727 × 10 −2 mg/ml, 394.68 U, and 4.2175 × 10 −2 s −1, respectively. Enzyme was noted to be active over a broad range of pH (6–12) and temperature (15–65°C), with maximum activity
at pH 11 and 60°C. CaCl 2 (1 mM), starch (1%), and sucrose (1%) imparted thermal stability at 65°C. Hg 2+, Cu 2+, Fe 3+, Zn 2+, Cd +, and Al 3+ inhibited enzyme activity, while 1 mM Co 2+ enhanced enzyme activity. Reducing agents enhanced enzyme activity at lower concentrations. The enzyme showed considerable
storage stability, and retained its activity in the presence of hydrocarbons, natural oils, surfactants, and most of the organic
solvents tested. Results indicate that the marine protease holds potential for use in the detergent industry and for varied
applications. 相似文献
18.
This paper reports the synthesis of azomethine-modified gold nanoparticles with azomethine (azomethine-AuNPs) in aqueous media, which were characterized by FT-IR spectroscopy, ultraviolet–visible spectroscopy (UV-Vis), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The azomethine-AuNPs were employed as colorimetric for Cr3+ and Co2+ ions at pH 6.2–7.5 and 8.1–9.1, at room temperature in aqueous solution. In the presence of Cr3+ and Co2+, the azomethine-AuNPs induce aggregation of the nanoparticles. Upon aggregation, the surface plasmon absorption band red-shifts so that the nanoparticle solution appears a blue color. The sensitivity of azomethine-AuNPs towards other metal ions, Mg2+, Mn2+, Cr6+, Na+, Ni2+, Ag+, Al3+, Ca2+, Cd2+, Cu2+, Fe2+, Fe3+, Hg2+, Cd2+, K+, Co3+, Ni2+, Pb2+, and Zn2+ are negligible. This highly selective sensor allows a direct quantitative assay of Co2+ and Cr3+ with colorimetric detection limits of 83.22 and 108 nM, respectively. 相似文献
19.
In order to characterize the potentially deleterious effects of toxic Hg 2+ and Cd 2+ on lipid membranes, we have studied their binding to liposomes whose composition mimicked erythrocyte membranes. Fluorescence
spectroscopy utilizing the concentration dependent quenching of Phen Green™ SK by Hg 2+ and Cd 2+ was found to be a sensitive tool to probe these interactions at metal concentrations ≤1 μM. We have systematically developed
a metal binding affinity assay to screen for the interactions of Hg 2+ or Cd 2+ with certain lipid classes. A biomimetic liposome system was developed that contained four major lipid classes of erythrocyte
membranes (zwitterionic lipids: phosphatidylcholine and phosphatidylethanolamine; negatively charged: phosphatidylserine and
neutral: cholesterol). In contrast to Hg 2+, which preferentially bound to the negatively charged phosphatidylserine compared to the zwitterionic components, Cd 2+ bound stronger to the two zwitterionic lipids. Thus, the observed distinct differences in the binding affinity of Hg 2+ and Cd 2+ for certain lipid classes together with their known effects on membrane properties represent an important first step toward
a better understanding the role of these interactions in the chronic toxicity of these metals. 相似文献
20.
The chromium (Cr III and Cr VI) removal capability of Rhizobium leguminosarum was checked by estimating the amount of chromium in the medium before and after inoculation. To determine the efficiency
of R. leguminosarum in removal of chromium, the influence of physical and chemical parameters such as temperature, pH and different concentrations
(0.1–1.0 mM) of trivalent (Cr III) and hexavalent (Cr VI) chromium were studied. The chromium removal in aqueous solution by different size of active and inactivated biomass and
immobilized cells of R. leguminosarum in a packed-bed column was also carried out. Results showed that in a medium containing up to 0.5 mM concentration of both
Cr III and Cr VI, R. leguminosarum showed optimal growth. The maximum chromium removal was at pH 7.0 and 35°C. Active biomass removed 84.4 ± 3.6% of Cr III and 77.3 ± 4.3% of Cr VI in 24 h of incubation time. However, inactivated biomass removed maximum chromium after 36 h of incubation. Immobilized bacterial
cells in a packed-bed column removed 86.4 ± 1.7% of Cr III and 83.8 ± 2.2% of Cr VI in 16 and 20 h of incubation time, respectively. 相似文献
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