Biosorption of methylene blue from aqueous solution using free and polysulfone-immobilized Corynebacterium glutamicum: batch and column studies

The amino acid fermentation industry waste, Corynebacterium glutamicum, has been found to possess excellent biosorption capacity towards methylene blue (MB). Due to practical difficulties in solid-liquid separation and biomass regeneration, C. glutamicum was immobilized in a polysulfone matrix. The pH edge experiments revealed that neutral or alkaline pH values favored MB biosorption. Isotherm experiments indicated that C. glutamicum, when in immobilized state, exhibited slightly inferior dye uptake compared to free biomass. Also considering the two forms, immobilized biomass took a long time to attain equilibrium. An attempt to identify the diffusion limitations in immobilized beads was successful, with the Weber-Morris model clearly indicating intraparticle as the rate controlling step. Regeneration of the free biomass was not possible as it tended to become damaged under strong acidic conditions. On the other hand, immobilized biomass performed well with 99% desorption of MB from the biosorbent with the aid of 0.1 mol/l HCl. The immobilized biomass was also successfully regenerated and reused for three cycles without significant loss in sorption capacity. An up-flow packed column loaded with immobilized biomass was employed for the removal of MB. The column performed well in the biosorption of MB, exhibiting a delayed and favorable breakthrough curve with MB uptake and % removal of 124 mg/g biomass and 70.1%, respectively.     

Biosorption of reactive dye by waste biomass of Nostoc linckia

Potential of spent biomass of a cyanobacterium, Nostoc linckia HA 46, from a hydrogen bioreactor was studied for biosorption of a textile dye, reactive red 198. The waste biomass was immobilized in calcium alginate and used for biosorption of the dye from aqueous solution using response surface methodology (RSM). Kinetics of the dye in aqueous solution was studied in batch mode. Interactive effects of initial dye concentration (100-500 mg/L), pH (2-6) and temperature (25-45 °C) on dye removal were examined using Box-Behnken design. Maximum adsorption capacity of the immobilized biomass was 93.5 mg/g at pH 2.0, initial concentration of 100 mg/L and 35 °C temperature, when 94% of the dye was removed. Fourier transform infrared (FT-IR) studies revealed that biosorption was mainly mediated by functional groups like hydroxyl, amide, carboxylate, methyl and methylene groups present on the cell surface.     

Kinetic and equilibrium studies on the biosorption of reactive black 5 dye by Aspergillus foetidus

An isolated fungus, Aspergillus foetidus had the ability to decolourize growth unsupportive medium containing 100 mg L(-1) of reactive black 5 (RB5) dye with >99% efficiency at acidic pH (2-3). Pre-treatment of fungal biomass by autoclaving or exposure to 0.1M sodium hydroxide facilitated more efficient uptake of dye as compared to untreated fungal biomass. Pre-equilibrium biosorption of RB5 dye onto fungus under different temperatures followed pseudo-second-order kinetic model with high degree of correlation coefficients (R(2)>0.99). Biosorption isotherm data fitted better into Freundlich model for lower concentrations of dye probably suggesting the heterogeneous nature of sorption process. Based on the Langmuir isotherm plots the maximum biosorption capacity (Q(0)) value was calculated to be 106 mg g(-1) at 50 degrees C for fungal biomass pre-treated with 0.1M NaOH. Thermodynamic studies revealed that the biosorption process was favourable, spontaneous and endothermic in nature. Recovery of both adsorbate (dye) and adsorbent (fungal biomass) was possible using sodium hydroxide. Recovered fungal biomass could be recycled number of times following desorption of dye using 0.1M NaOH. Fungal biomass pre-treated with NaOH was efficient in decolourizing solution containing mixture of dyes as well as composite raw industrial effluent generated from leather, pharmaceutical and dye manufacturing company.     

Biosorption of uranium by cross-linked and alginate immobilized residual biomass from distillery spent wash

Residual biomass from a whiskey distillery was examined for its ability to function as a biosorbent for uranium. Biomass recovered and lyophilised exhibited a maximum biosorption capacity of 165–170?mg uranium/g dry weight biomass at 15?°C. With a view towards the development of continuous or semi-continuous flow biosorption processes it was decided to immobilize the material by (1) cross-linking with formaldehyde and (2) introducing that material into alginate matrices. Cross-linking the recovered biomass resulted in the formation of a biosorbent preparation with a maximum biosorption capacity of 185–190?mg/g dry weight biomass at 15?°C. Following immobilization of biomass in alginate matrices it was found that the total amount of uranium bound to the matrix did not change with increasing amounts of biomass immobilized. It was found however, that the proportion of uranium bound to the biomass within the alginate-biomass matrix increased with increasing biomass concentration. Further analysis of these preparations demonstrated that the alginate-biomass matrix had a maximum biosorption capacity of 220?mg uranium/g dry weight of the matrix, even at low concentrations of biomass.     

Waste biomass of Nostoc linckia as adsorbent of crystal violet dye: Optimization based on statistical model

The potential of spent biomass of a hydrogen producing cyanobacterial strain Nostoc linckia from a hydrogen fermentor was studied for decolorization of a tri-phenylmethane dye, crystal violet. The waste cyanobacterial biomass immobilized in calcium alginate was used as a biosorbent and the process variables were optimized for maximum dye removal using the statistical response surface methodology (RSM). Batch mode experiments were performed to determine the kinetic behavior of the dye in aqueous solution allowing the computation of kinetic parameters. Influence of interacting parameters like temperature (25-35 °C), pH (4-8), initial dye concentration (100-200 mg/L) and cyanobacterial dose (0.2-0.4 g) on dye removal were examined using central composite design (CCD) which included two additional levels for each parameter. Second-order polynomial regression model, was applied which was statistically validated using analysis of variance. Ability of the immobilized biomass to decolorize the dye was maximum (72%) at pH 8.0, temperature 35 °C, 200 mg/L initial dye concentration and 0.2 g cyanobacterial dose. Adsorption of the dye on cell surface was further confirmed by scanning electron micrographs of the biomass before and after dye loading. FT-IR studies revealed that decolorization was due to biosorption mediated mainly by functional groups like hydroxyl, amide, carboxylate, methyl and methylene groups present on the cell surface.     

Preparation of PEI-coated bacterial biosorbent in water solution: optimization of manufacturing conditions using response surface methodology

The aim of this study is to optimize preparation method of polyethyleneimine (PEI)-coated bacterial biosorbent in water as reaction media using fermentation waste biomass of Corynebacterium glutamicum as a raw material. The fermentation waste biomass of C. glutamicum and Reactive Red 4 were used as model raw bacterium and pollutant. Major factors affecting the performance of PEI-coated biosorbent were the amounts of polymer (PEI) and cross-linker glutaraldehyde (GA). These factors were optimized through response surface methodology (RSM) with two-level-two-factor (2(2)) full factorial central composite design. As a result, the optimum conditions were found to be 4.29 g of PEI and 0.15 mL of GA, with 10 g of the biomass, where the sorption capacity was enhanced 4.52-fold compared to that of the raw biomass. Therefore, this simple, cost-effective, and water-based method could be a useful modification tool for the development of a high performance biosorbent for removing anionic pollutants.     

Biosorption of anionic textile dyes by nonviable biomass of fungi and yeast

The nonviable biomass of Aspergillus niger, Aspergillus japonica, Rhizopus nigricans, Rhizopus arrhizus, and Saccharomyces cerevisiae were screened for biosorption of textile dyes. The selected anionic reactive dyes were C.I. Reactive Black 8, C.I. Reactive Brown 9, C.I. Reactive Green 19, C.I. Reactive Blue 38, and C.I. Reactive Blue 3. Experiments were conducted at initial dye concentration of 50, 100, 150 and 200mg/L. The effect of initial dye concentration, dose of biosorbent loading, temperature, and pH on adsorption kinetics was studied. S. cerevisiae and R. nigricans were good biosorbents at initial dye concentration of 50mg/L, 1g% (w/v) biomass loading and 29+/-1 degrees C. R. nigricans adsorbed 90-96% dye in 15min, at 20 degrees C and pH 6.0. The data showed an optimal fit to the Langmuir and Freundlich isotherms. The maximum uptake capacity (Q(o)) for the selected dyes was in the range 112-204mg/g biomass.     

Lead biosorption by waste biomass of Corynebacterium glutamicum generated from lysine fermentation process

Biomass waste, mainly Corynebacterium glutamicum, is generated from large-scale lysine fermentation process. In this study, protonated C. glutamicum biomass was evaluated as a biosorbent for the removal of lead from synthetic wastewater. As Pb2+ were bound to the biomass, the solution pH deceased, indicating that protons in the biomass were exchanged with lead ions. The Corynebacterium biomass bound Pb2+ at up to 2.74 mmol g(-1) at pH 5, where lead does not precipitate. Compared with other biosorbents and conventional sorbents, such as natural zeolite, activated carbon and synthetic ion exchange resin, the protonated C. glutamicum biomass was considered to be a useful biomaterial for lead biosorption.     

Reuse of waste beer yeast sludge for biosorptive decolorization of reactive blue 49 from aqueous solution

Reactive blue 49 was removed from aqueous solution by biosorption using powder waste sludge composed of Saccharomyces cerevisiae from the beer-brewing industry. The effect of initial pH, temperature and the biosorption thermodynamics, equilibrium, kinetics was investigated in this study. It was found that the biosorption capacity was at maximum at initial pH 3, that the effect of temperature on biosorption of reactive blue 49 was only slight in relation to the large biosorption capacity (25°C, 361 mg g⁻¹) according as the biosorption capacity decreased only 43 mg g⁻¹ at the temperature increased from 25 to 50°C. The biosorption was spontaneous, exothermic in nature and the dye molecules movements decreased slightly in random at the solid/liquid interface during the biosorption of dye on biosorbents. The biosorption equilibrium data could be described by Freundich isotherm model. The biosorption rates were found to be consistent with a pseudo-second-order kinetics model. The functional group interaction analysis between waste beer yeast sludge and reactive blue 49 by the aid of Fourier transform infrared (abbr. FTIR) spectroscopy indicated that amino components involved in protein participated in the biosorption process, which may be achieved by the mutual electrostatic adsorption process between the positively charged amino groups in waste beer yeast sludge with negatively charged sulfonic groups in reactive blue 49.     

Studies on the biosorption of uranium by Talaromyces emersonii CBS 814.70 biomass

Residual biomass, produced by the thermophilic fungus, Talaromyces emersonii CBS 814.70, following growth on glucose-containing media, was examined for its ability to take up uranium from aqueous solution. It was found that the biomass had a relatively high observed biosorption capacity for the uranium (280 mg/g dry weight biomass). The calculated maximum biosorption capacity obtained by fitting the data to a Langmuir model was calculated to be 323 mg uranium/g dry weight biomass. Pretreatment of the biomass with either dilute HCl or NaOH brought about a significant decrease in biosorptive capacity for uranium. Studies on the effects of variation in temperature on the biosorptive capacity demonstrated no significant change in binding between 20°C and 60°C. However, a significant decrease in biosorptive capacity was observed at 5°C. Binding of uranium to the biomass at all temperatures reached equilibrium within 2 min. While the routine binding assays were performed at pH 5.0, adjustment of the pH to 3.0 gave rise to a significant decrease in biosorption capacity by the biomass. The biosorptive capacity of the biomass for uranium was increased when extraction from solution in sea-water was examined.     

Biosorption of an Azo Dye by <Emphasis Type="Italic">Aspergillus niger</Emphasis> and <Emphasis Type="Italic">Trichoderma</Emphasis> sp. Fungal Biomasses

Biosorption is an eco-friendly and cost-effective method for treating the dye house effluents. Aspergillus niger and Trichoderma sp. were cultivated in bulk and biomasses used as biosorbents for the biosorption of an azo dye Orange G. Batch biosorption studies were performed for the removal of Orange G from aqueous solutions by varying the parameters like initial aqueous phase pH, biomass dosage, and initial dye concentration. It was found that the maximum biosorption was occurred at pH 2. Experimental data were analyzed by model equations such as Langmuir and Freundlich isotherms, and it was found that both the isotherm models best fitted the adsorption data. The monolayer saturation capacity was 0.48 mg/g for Aspergillus niger and 0.45 mg/g for Trichoderma sp. biomasses. The biosorption kinetic data were tested with pseudo first-order and pseudo second-order rate equations, and it was found that the pseudo second-order model fitted the data well for both the biomasses. The rate constant for the pseudo second-order model was found to be 10–0.8 (g/mg min⁻¹) for Aspergillus niger and 8–0.4 (g/mg min⁻¹) for Trichoderma sp. by varying the initial dye concentrations from 5 to 25 mg/l. It was found that the biomass obtained from Aspergillus niger was a better biosorbent for the biosorption of Orange G dye when compared to Trichoderma sp.     

Reinforcement of carboxyl groups in the surface of Corynebacterium glutamicum biomass for effective removal of basic dyes

The biomass of Corynebacterium glutamicum was treated with poly(amic acid) to improve the biosorption of Basic Blue 3 (BB3) from aqueous solution. The grafting of poly(amic acid) onto the biomass surface increased the density of the carboxyl groups. The UV-spectrum revealed that strong acidic (pH  2) and basic conditions (pH  11) resulted in the precipitation of BB3. Therefore, pH edge experiments were conducted only within the range 3–10; these results indicated that electrostatic attraction between carboxyl groups of C. glutamicum and BB3 dye cations was favored under alkaline conditions. From the Langmuir model, poly(amic acid)-modified biomass gave a maximum uptake of 173.6 mg/g at pH 9, compared to 52.8 mg/g by the raw biomass. The biosorption kinetics was found to be fast; with equilibrium attained within 10 min. The increase in the ionic strength strongly affected the uptake of BB3 for both forms of C. glutamicum.     

Biosorption of a textile dye (Acid Blue 40) by cone biomass of Thuja orientalis: estimation of equilibrium, thermodynamic and kinetic parameters

Biosorption of Acid Blue 40 (AB40) onto cone biomass of Thuja orientalis was studied with variation in the parameters of pH, contact time, biosorbent and dye concentration and temperature to estimate the equilibrium, thermodynamic and kinetic parameters. The AB40 biosorption was fast and the equilibrium was attained within 50 min. Equilibrium data fitted well to the Langmuir isotherm model in the studied concentration range of AB40 and at various temperatures. Maximum biosorption capacity (q(max)) for AB40 was 2.05 x 10(-4)mol g(-1) or 97.06 mg g(-1) at 20 degrees C. The changes of Gibbs free energy, enthalpy and entropy of biosorption were also evaluated for the biosorption of AB40 onto T. orientalis. The results indicate that the biosorption was spontaneous and exothermic. Kinetics of biosorption of AB40 was analyzed and rate constants were also derived and the results show that the pseudo-second-order kinetic model agrees very well with the experimental data.     

Studies on the biosorption of uranium by a thermotolerant, ethanol-producing strain of Kluyveromyces marxianus

The ability of residual biomass from the thermotolerant ethanol-producing yeast strain Kluyveromyces marxianus IMB3 to function as a biosorbent for uranium has been examined. It was found that the biomass had an observed maximum biosorption capacity of 120?mg U/g dry weight of biomass. The calculated value for the biosorption maximum, obtained by fitting the data to the Langmuir model was found to be 130?mg U/g dry weight biomass. Maximum biosorption capacities were examined at a number of temperatures and both the observed and calculated values obtained for those capacities increased with increasing temperature. Decreasing the pH of the biosorbate solution resulted in a decrease in uptake capacity. When biosorption reactions were carried out using sea-water as the diluent it was found that the maximum biosorption capacity of the biomass increased significantly. Using transmission electron microscopy, uranium crystals were shown to be concentrated on the outer surface of the cell wall, although uranium deposition was also observed in the interior of the cell.     

橘子皮对水中亚甲蓝的吸附性能

用低值廉价的橘子皮作为吸附剂对亚甲蓝染料废水进行吸附研究,考察了吸附平衡时间、溶液pH、染料浓度等因素对亚甲蓝吸附的影响,橘子皮主要含有羧基、氨基和磺酸基,橘子皮生物吸附剂对MB的吸附所需平衡时间为1小时,在pH=10的条件下,生物吸附剂对MB的最大吸附量(qm)为370.3±31.0 mg/g,等温吸附线符合Langmuir和Freundlich模式,研究结果表明：橘子皮对染料废水的吸附只需很短的时间则可达到吸附饱和,且吸附量大,具有很好的应用前景。     

Biosorption of reactive and basic dyes using fermentation waste <Emphasis Type="Italic">Corynebacterium glutamicum</Emphasis>: the effects of pH and salt concentration and characterization of the binding sites

A low cost biosorbent, Corynebacterium glutamicum, was studied for the sorption of Reactive Red 4 (RR 4) and Methylene Blue (MB). The equilibrium isotherm data were well described by the Langmuir model. pH edge experiments showed that pH of the solution was an important controlling parameter in the sorption process. In the case of RR 4, with increases in the pH from 2 to 10, the uptake decreased from 52 to 1 mg/g; conversely, the uptake of MB increased and the maximum MB uptake was obtained at pH ≥ 9. An increase in the salt concentration strongly influenced the uptake of MB, but had no effect on that of RR 4. In order to identify the binding sites for the dye molecules, the biosorbent was potentiometrically titrated, the results of which showed the presents of four major functional group types on the biomass surface, which were confirmed by FTIR analysis. It was found that positively charged amine groups (Biomass-NH₃ ⁺) were the likely binding sites for anionic RR 4, and negatively charged carboxyl (Biomass-COO⁻) and phosphate groups (Biomass-HPO₄ ⁻) played a role in the electrostatic attraction of cationic MB.     

Co2+, Cu2+, and Zn2+ accumulation by cyanobacterium Spirulina platensis

The Spirulina platensis biomass was characterized for its metal accumulation as a function of pH, external metal concentration, equilibrium isotherms, kinetics, effect of co-ions under free (living cells, lyophilized, and oven-dried) and immobilized (Ca-alginate and polyacrylamide gel) conditions. The maximum metal biosorption by S. platensis biomass was observed at pH 6.0 with free and immobilized biomass. The studies on equilibrium isotherm experiments showed highest maximum metal loading by living cells (181.0 +/- 13.1 mg Co(2+)/g, 272.1 +/- 29.4 mg Cu(2+)/g and 250.3 +/- 26.4 mg Zn(2+)/g) followed by lyophilized (79.7 +/- 9.6 mg Co(2+)/g, 250.0 +/- 22.4 mg Cu(2+)/g and 111.2 +/- 9.8 mg Zn(2+)/g) and oven-dried (25.9 +/- 1.9 mg Co(2+)/g, 160.0 +/- 14.2 mg Cu(2+)/g and 35.1 +/- 2.7 mg Zn(2+)/g) biomass of S. platensis on a dry weight basis. The polyacrylamide gel (PAG) immobilization of lyophilized biomass found to be superior over Ca-alginate (Ca-Alg) and did not interfere with the S. platensis biomass biosorption capacity, yielding 25% of metal loading after PAG entrapment. The time-dependent metal biosorption in both the free and immobilized form revealed existence of two phases involving an initial rapid phase (which lasted for 1-2 min) contributing 63-77% of total biosorption, followed by a slower phase that continued for 2 h. The metal elution studies conducted using various reagents showed more than 90% elution with mineral acids, calcium salts, and Na(2)EDTA with free (lyophilized or oven-dried) as well as immobilized biomass. The experiments conducted to examine the suitability of PAG-immobilized S. platensis biomass over multiple cycles of Co(2+), Cu(2+), and Zn(2+) sorption and elution showed that the same PAG cubes can be reused for at least seven cycles with high efficiency.