• Environmental Engineering Research
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• v.24 no.1
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• pp.31-37
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• 2019

In this paper the results of the biosorption of lead(II) and cadmium(II) with sugarcane bagasse in fixed bed columns are presented. Experimental data were fitted to several models describing the rupture curve for single-component and two-component systems. The percentages of removal of lead and cadmium in single-component systems are 91% and 90%, respectively. In lead-cadmium bicomponent systems the percentage of elimination of lead was 90% and cadmium 92%. In single-component systems, Yoon-Nelson and Thomas models successfully reproduce the rupture curves. In two-component system, the Dose-Response model was the best one reproducing the experimental rupture curves in the entire measured range.

• Environmental Engineering Research
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• v.20 no.1
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• pp.41-50
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• 2015

The cyanobacterium Anabaena doliolum Ind1 isolated from a coal mining site was tested for removal of cadmium at optimum pH 7.0 and temperature $25^{\circ}C$. The organism recorded high percentage of metal removal (92-69%) within seven days of exposure to 0.5-2.0 ppm cadmium. Biosorption onto the cell surface was the primary mode of metal removal. Fourier transform infrared spectroscopy (FTIR) established hydroxyl, amides, carboxyl, sulphate and carbonyl groups to be the major functional groups on the cell surface involved in cadmium binding. Cellular ultrastructure and a range of vital physiological processes (i.e., photosynthetic pigments, respiration, photosynthesis, heterocyst frequency and nitrogenase activity) remained unaffected upon 0.5 ppm treatment; higher concentrations of cadmium exerted visible adverse effects. Amongst the five photosynthetic pigments tested, phycocyanin was the most targeted pigment (inhibition was 15-89%). Both respiration and photosynthetic activities were inhibited by cadmium with more severe effect seen on respiration. 2.0 ppm cadmium exposure also had drastic negative effect on nitrogenase activity (87% decreased).

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.846-853
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• 2016

We displayed four types of Solanum nigrum metallothionein (SMT) for the first time on the surface of Saccharomyces cerevisiae using an α-agglutinin-based display system. The SMT genes were amplified by RT-PCR. The plasmid pYES2 was used to construct the expression vector. Transformed yeast strains were confirmed by PCR amplification and custom sequencing. Surface-expressed metallothioneins were indirectly indicated by the enhanced cadmium sorption capacity. Flame atomic absorption spectrophotometry was used to examine the concentration of Cd²⁺ in this study. The transformed yeast strains showed much higher resistance ability to Cd²⁺ compared with the control. Strikingly, their Cd²⁺ accumulation was almost twice as much as that of the wild-type yeast cells. Furthermore, surface-engineered yeast strains could effectively adsorb ultra-trace cadmium and accumulate Cd²⁺ under a wide range of pH levels, from 3 to 7, without disturbing the Cu²⁺ and Hg²⁺. Four types of surfaceengineered Saccharomyces cerevisiae strains were constructed and they could be used to purify Cd²⁺-contaminated water and adsorb ultra-trace cadmium effectively. The surface-engineered Saccharomyces cerevisiae strains would be useful tools for the bioremediation and biosorption of environmental cadmium contaminants.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.249-254
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• 1999

The biosorption and desorption of Cd were carried out using brown marine algae, known as the good biosorbent of heavy metals. The content of alginate bound to light metals could be changed by the physical and the chemical pretreatment of Sargassum fluitans biomass. The Cd uptake was independent of the alginate content. In case of protonated biomass, Cd uptake was the lowest because the alginic acid of biomass was dissolved to cadmium solution during the biosorption. The maximum Cd uptake of Sargassum biomass was ranged from 79 mg/g to 139 mg/g. In case of raw biomass, the higher the alginate content of biomass, the higher was the Cd uptake. 100% of Cd and light metals sorbed in the biomass were eluted at 0.1N HCI(pH 1.1). However, the elution efficiency in $CaCl_2$ and $Ca{(NO_3)}_2$solution was varied by the concentration, the solid to liquid ratio and the pH of calcium solution. The distribution coefficient between Cd and protons in the desorption solution at pH ranged from 1.6 to 2.9 was observed on the constant stoichometric coefficient(1.3).

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.67-71
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• 2006

This paper compares regression and neural network modeling approaches to predict competitive biosorption equilibrium data. The regression approach is based on the fitting of modified Langmuir-type isotherm models to experimental data. Neural networks, on the other hand, are non-parametric statistical estimators capable of identifying patterns in data and correlations between input and output. Our results show that the neural network approach outperforms traditional regression-based modeling in correlating and predicting the simultaneous uptake of copper and cadmium by a microbial biosorbent. The neural network is capable of accurately predicting unseen data when provided with limited amounts of data for training. Because neural networks are purely data-driven models, they are more suitable for obtaining accurate predictions than for probing the physical nature of the biosorption process.

• The Korean Journal of Ecology
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• v.22 no.1
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• pp.39-43
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• 1999

Serratia marcescens, an enterobacterium of gram-negative bacteria, is characterized by resistance of the admium. Cadmium sensitive PM strain did not grow in the medium at cadmium concentration of 50 ppm. PA strain was induced to accommodate to cadmium by cultivating the mother strain (PC strain) in the medium with 50 ppm cadmium. As compared with PC and PM strains, PA strain revealed the excellent growth in cadmium media and accumulated four to five times higher cadmium concentration in cell than other strains. PA strain accumulated 23% of cadmium in cells when cultured in medium treated with 100 ppm cadmium and this cadmium was more accumulated in cytosol fractions than membrane fractions. Analysis by TEM indicated that cadmium was concentrated as a form of granule in cytosol. In protein patterns of cell after the treatment of cadmium, two inducible proteins (28 KDa and 64 KDa) and one reducible protein (45 KDa) were detected by SDS-PAGE. By Atomic Absorption Spectrophotometer, the amounts of cadmium attached to inducible proteins of 28 KDa and 64 KDa were 318.28 ㎍ and 325.37 ㎍ per gram of protein, respectively. It is assumed that these inducible proteins play an important role in the mechanism of cadmium accumulation in cells. A plasmid of 23Kbp was found in S. marcescens. The ability of resistance to cadmium in plasmid was confirmed by curing experiments.

• Environmental Engineering Research
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• v.17 no.3
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• pp.125-132
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• 2012

The removal of Cd(II) and Cu(II) from aqueous solution by an agricultural solid waste biomass prepared from Moringa oleifera bark (MOB) was investigated. The biosorbent was characterized by Fourier transform infrared spectroscopy and elemental analysis. Furthermore, the effect of initial pH, contact time, biosorbent dosage, initial metal ion concentration and temperature on the biosorption of Cd(II) and Cu(II) were studied using the batch sorption technique. Kinetic studies indicated that the biosorption process of the metal ions followed the pseudo-second order model. The biosorption data was analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models. Based on the Langmuir isotherm, the maximum biosorption capacities for Cd(II) and Cu(II) onto MOB were 39.41 and 36.59 mg/g at 323 K, respectively. The thermodynamic parameters, Gibbs free energy (${\Delta}G^o$), enthalpy (${\Delta}H^o$), and entropy (${\Delta}S^o$) changes, were also calculated, and the values indicated that the biosorption process was endothermic, spontaneous and feasible in the temperature range of 303-323 K. It was concluded that MOB powder can be used as an effective, low cost, and environmentally friendly biosorbent for the removal of Cd(II) and Cu(II) ions from aqueous solution.

• Journal of Life Science
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• v.16 no.6
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• pp.877-883
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• 2006

An alternative method to remove and recover heavy metals is biosorption based on metal-sequestering properties of natural or biological origin. In this study, the effects of factors such as temperature, pH, initial concentration of lead, and initial amount of biomass on biosorption of lead using Aureobasdium pullulans were investigated. A. pullulans has an excellent selectivity to remove lead than other heavy metals such as cadmium, chromium, nickel in pure and mixed solution. The optimum temperature of biosorption with A. pullulans was $40^{\circ}C$ and the amount of removal increased at high pH. The higher initial lead concentration or the lower cell dry weight, the higher amount of lead was adsorbed. The adsorption isotherm of lead was accorded with Freundlich model. The adsorption capacity and initial adsorption rate of living A. pullulans were about twice higher than that of dead one.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.431-435
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• 2000

The goal of this research is to compare the metal binding characteristics of an anoxic selector activated sludge system and a conventional activated sludge system. Metal biosorption by biomass harvested from experimental systems was determined by a series of batch experiments. Heavy metals studied in this research were zinc, cadmium, and nickel. The sorption isotherm showed that the selector sludge had significantly higher sorption capacity than did the control sludge. Metal biosorption behavior closely followed a Freundlich isotherm model for equilibrium concentrations. ECP contents of biomass estimated by alkali extraction technique showed that ECP levels in the selector sludge significantly higher than that in the sludge harvested from the conventional system, indicating that the higher metal sorption capacity of selector sludge may be due to the selection of the ECP-producing bacteria (i.e., Zoogloea sp.) by the selector system.

• Journal of Microbiology
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• v.40 no.1
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• pp.51-54
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• 2002

Heavy metal adsorptions of four streptomycetes were compared with each other, Among the test strains, Streptomyces viridochromogenes showed the most efficient metal binding activity, which was carried out by cell wall as well as freeze-dried mycelium. An order of adsorption potential (zinc > copper > lead > cadmium) was observed in single metal reactions, whereas this adsorption order was disturbed in mixed-metal reactions. The metal adsorption reactions were very fast, pH dependent and culture age-independen, suggestive of a physico-chemical reaction between cell wall components and heavy metal ions. The metal tolerant stains presented the weakest adsorbing activity, indicating that the metal biosorption was not the basis of the metal tolerance.