Metal recovery by aged beads prepared using cell-suspension from the waste of beer fermentation broth

Lead, copper, and cadmium were adsorbed onto aged calcium alginate beads containing cell-suspension from the waste of beer fermentation broth. Beads prepared by adding 0.6% (w/v) sodium alginate into the cell suspension from the waste of beer fermentation broth and making the cell suspension drop into the 1% (w/v) calcium alginate solution were stored in the 1% (w/v) calcium chloride solution for 1 year. The specific metal uptake of the aged cell-suspension immobilized bead was 312 mg Pb²⁺, 158 mg Cu²⁺, and 112 mg Cd²⁺/g bead dry weight at pH 7.5 of the metal solution, respectively. The relation between the specific metal uptake by the aged cell-suspension immobilized beads and the equilibrium metal concentration was nonlinearly regressed and well described by the Freundlich isotherm. The specific cadmium uptake capacity of aged cell-suspension immobilized beads was between the specific cadmium uptake capacities of commercial beads Duolite GT-73 and Amberite IRA-400 and higher than those of the fresh Saccharomyces cerevisiae ATCC 834 and Saccharomyces cerevisiae ATCC 24858 immobilized beads.     

Encapsulation of Rhodopseudomonas palustris KTSSR54 using beads from alginate/starch blends

Alginate beads are a promising carrier for biofertilizer delivery, but still possess drawbacks of low mechanical strength and bead shrinkage that result in poor appearance and inadequate cell protection. Blending alginate with starch was proposed as a solution to these problems, and here alginate hydrogels were prepared using a 2% (w/v) alginate dispersion blended with varying contents of gelatinized starch (0–5% w/v). The interaction produced a viscosity synergism that increased the complexity of the matrix network in the alginate/starch blends, producing a more suitable matrix for cell entrapment. Hydrogen bonding between alginate and starch influenced the viscosity of the various solutions in a way that was consistent with the FTIR spectra. The starch content also helped beads retain their spherical shape after drying. The starch supported the entrapment of bacterial cells (plant growth-promoting bacterium Rhodopseudomonas palustris KTSSR54 as biofertilizer) in the matrix, which reduced cell loss. The highest entrapment efficiency of 70.83% was obtained at 4% (w/v) starch, while the entrapment efficiency of control beads was 50.56%. Overall, the appropriate content of starch mixed with alginate is conducive to changes in the morphology of microcapsules and increases in the amount of biological encapsulation.     

Evaluation of lipase from Burkholderia cepacia immobilized in alginate beads and application in the synthesis of banana flavor (isoamyl acetate)

The alginate in bead forms was used to immobilize Burkholderia cepacia lipase. The microencapsulation technique for lipase entrapment was a 2% (w/v) of sodium alginate concentration prepared by ionic gelation using calcium chloride as the cross-linking agent in a gelling solution. The beads were tested in different solvents as acetone, chloroform, toluene, n-hexane, and n-heptane. Over a 5-day period (120?h), the n-heptane maintained the reasonable (excellent) residual activity of the immobilized lipase. Morphological studies on reused beads and new beads were performed. All beads for isoamyl acetate yield were tested. The reused bead leaches substantially, with a maximum ester yield of 92%. With modifications in the molar ratios, the synthesis of banana flavor (isoamyl acetate) was performed in both the alcohol per acid and acid per alcohol excesses.     

Zirconium mesostructures immobilized in calcium alginate for phosphate removal

Eutrophication caused by the excessive supply of phosphate to water bodies has been considered as one of the most important environmental problems. In this study, the powder of zirconium mesostructure (ZM), which was prepared with the template of surfactant, was immobilized in calcium alginate for practical application and the resulting material was tested to evaluate the phosphate removal efficiency. Sorption isotherms and kinetic parameters were obtained by using the entrapped ZM beads with 30 to 60% of ZM. The maximum sorption capacity increased with the higher ZM content. Q _max in Langmuir isotherm was 51.74 mg/g for 60% of ZM with 7 mm of size. The smaller the particle size of the ZM beads, the faster the rate of phosphate removal, because the phosphate ions had less distance to reach the internal pores of the immobilized ZM beads. Chemical and electrochemical regeneration techniques were compared. Phosphates adsorbed on the ZM beads were effectively desorbed with NaCl, NaOH, and Na₂SO₄ solutions. An electrochemical regeneration system consisting of an anion exchange membrane between two platinum-coated titanium electrodes was successfully used to desorb and regenerate the phosphate-saturated ZM beads. Complete regeneration was reached under optimal experimental conditions. Chemical and electrochemical regeneration proved the reusability of the bead form of the entrapped ZM, and will enhance the economical performance of the phosphate treatment process.     

Optimization of lactic acid production from whey by L casei NRRL B‐441 immobilized in chitosan stabilized Ca‐alginate beads

The production of lactic acid from whey by Lactobacillus casei NRRL B‐441 immobilized in chitosan‐stabilized Ca‐alginate beads was investigated. Higher lactic acid production and lower cell leakage were observed with alginate–chitosan beads compared with Ca‐alginate beads. The highest lactic acid concentration (131.2 g dm^?3) was obtained with cells entrapped in 1.3–1.7 mm alginate–chitosan beads prepared from 2% (w/v) Na‐alginate. The gel beads produced lactic acid for five consecutive batch fermentations without marked activity loss and deformation. Response surface methodology was used to investigate the effects of three fermentation parameters (initial sugar, yeast extract and calcium carbonate concentrations) on the concentration of lactic acid. Results of the statistical analysis showed that the fit of the model was good in all cases. Initial sugar, yeast extract and calcium carbonate concentrations had a strong linear effect on lactic acid production. The maximum lactic acid concentration of 136.3 g dm^?3 was obtained at the optimum concentrations of process variables (initial sugar 147.35 g dm^?3, yeast extract 28.81 g dm^?3, CaCO₃ 97.55 g dm^?3). These values were obtained by fitting of the experimental data to the model equation. The response surface methodology was found to be useful in optimizing and determining the interactions among process variables in lactic acid production using alginate–chitosan‐immobilized cells. Copyright © 2005 Society of Chemical Industry     

Immobilization of malto‐oligosaccharide forming α‐amylase from Bacillus subtilis KCC103: properties and application in starch hydrolysis

BACKGROUND: A malto‐oligosaccharide forming α‐amylase from Bacillus subtilis KCC103 immobilized in calcium alginate beads was repeatedly used in batch processes of starch hydrolysis. The degree of starch degradation and operational stability of the immobilized system were optimized by varying the physical characteristics and composition of the beads. The products formed from hydrolysis of various starches by α‐amylase immobilized in different supports were analyzed. RESULTS: Immobilized beads prepared from 3% (w/v) alginate and 4% (w/v) CaCl₂ were suitable for up to 10 repeated uses, losing only 25% of their efficiency. On addition of 1% silica gel to alginate prior to gelation, the operational stability of the immobilized enzyme was enhanced to 20 cycles of operation, retaining > 90% of the initial efficiency. Distribution of malto‐oligosaccharides in the starch hydrolyzate depended on the type of starch, reaction time and mode of immobilization. Soluble starch and potato starch formed a wide range of malto‐oligosaccharides (G1–G5). Starches from wheat, rice and corn formed a narrow range of smaller oligosaccharides (G1–G3) as the major products. CONCLUSION: The immobilized beads of α‐amylase from KCC103 prepared from alginate plus silica gel showed high efficiency and operational stability for hydrolysis of starch. This immobilized system is useful for production of malto‐oligosaccharides applied in the food and pharmaceutical industries. Since this KCC103 amylase can be produced at low cost utilizing agro‐residues in a short time and immobilized enzyme can be recycled, the overall cost of malto‐oligosaccharide production would be economical for industrial application. Copyright © 2008 Society of Chemical Industry     

Effects of Acylation and Crosslinking on the Material Properties and Cadmium Ion Adsorption Capacity of Porous Chitosan Beads

Abstract

Chitosan is a novel glucosamine biopolymer derived from the shells of marine organisms. This biopolymer is very attractive for heavy metal ion separations from wastewater because it is selective for toxic transition metal ions over less toxic alkali or alkane earth metal ions. Highly porous, 3-mm chitosan beads were prepared by an aqueous phase-inversion technique for casting gel beads followed by freeze drying. In the attempt to simultaneously improve material properties and adsorption capacity, chitosan was chemically modified by 1) homogeneous acylation of amine groups with nonanoyl chloride before bead casting, and 2) heterogeneous crosslinking of linear chitosan chains with the bifunctional reagent glutaric dialdehyde (GA) after bead casting but before freeze drying. The random addition of C₈ hydrocarbon side chains to about 7% of the amine groups on uncrosslinked chitosan beads via N-acylation improved the saturation adsorption capacity from 169 to 216 mg Cd²⁺/g-bead at saturation (pH 6.5, 25°C) but only slightly reduced solubility in acid solution. Crosslinking of the N-acylated chitosan beads with 0.125 to 2.5 wt% GA in the crosslinking bath increased the internal surface area from 40 to 224 m²/g and rendered the beads insoluble in 1 M acetic acid (pH 2.36). However, crosslinking of the N-acylated chitosan beads reduced the saturation adsorption capacity to 136 mg Cd²⁺/g-bead at 0.75 wt% GA and 86 mg Cd²⁺/g-bead at 2.5 wt% GA. Crosslinking also significantly reduced the compression strength. There was no clear relationship between internal surface area and adsorption capacity, suggesting that the adsorbed cadmium was not uniformly loaded into the bead.     

Copper and cadmium extraction from highly concentrated phosphoric acid solutions using calcium alginate gels enclosing bis(2,4,4‐trimethylpentyl)thiophosphinic acid

The availability of alginate gels enclosing Cyanex 302 [bis(2,4,4‐trimethylpentyl)thiophosphinic acid] for the uptake of cadmium and copper from highly concentrated solutions of industrial phosphoric acid wet process phosphoric acid (WPA)] was studied. For this purpose, beads of alginate gels enclosing microdrops of kerosene solutions of the industrial extractant Cyanex 302 at different concentrations were prepared. The experimental procedure gives rise to a composite bead in which alginate is the continuous phase and the organic extractant forms the discrete homogeneously distributed phase within the bead. The equilibrium in this three‐phase system (phosphoric acid–extractant solution–alginate gel) was modelled in terms of the corresponding distribution factors, the main chemical reactions and their equilibrium constants. Retention isotherms of both metal ions were obtained experimentally at four concentrations (1.0, 2.5, 5.0 and 7.5 mol L^?1) of pure phosphoric acid. High metal removal efficiency, due to liquid–liquid extraction processes, was observed even in the most acidic conditions. High values of the extraction constants were estimated, with the distribution coefficients between aqueous and alginate phase being near unity. Finally, the results obtained with industrial WPA are in close agreement with those predicted by the physicochemical model developed in synthetic media. Copyright © 2006 Society of Chemical Industry     

Cadmium Recovery from HCl Solutions Using Cyanex 301 and Cyanex 302 Immobilized in Alginate Capsules (Matrix-Type vs. Mononuclear-Type Mode of Encapsulation)

Cyanex 301 and Cyanex 302 have been immobilized in alginate capsules by two methods: the matrix-type process immobilizes the extractant as homogeneous-dispersed vesicles while the mononuclear mode consists of encapsulation of the extractant drop by an alginate layer. The influence of HCl concentration on Cd(II) removal is discussed as a function of acid concentration and extractant. The sorption isotherms are fitted by the Langmuir model; maximum sorption capacities reach up to 42 mg Cd g^?1 in 0.1 M HCl. Uptake kinetics are controlled by resistance to intraparticle diffusion. Cadmium is desorbed using either 1 M HNO₃ or 1 M thiourea/1 M HCl solutions.     

Preparation of lactic acid bacteria-enclosing alginate beads in emulsion system: effect of preparation parameters on bead characteristics

The immobilization of plant growth-promoting bacteria in biodegradable polymeric supports is effective in providing them with a suitable microenvironment for increased survival, compared to free bacteria, in agricultural land. In this study, we optimized the preparation parameters for bacteria-enclosing calcium alginate gel beads with a view to large-scale production. An emulsion system was used and the optimization was based on alginate bead recovery and entrapment efficiency of viable bacteria. Lactic acid bacteria were used as a plant growth-promoting bacteria. The optimized conditions were as follows: the concentration of calcium chloride in the aqueous phases was 1.1% (w/v), the volume ratio of alginate solution to total aqueous phases was 0.93, and the agitation time was 0.5–1.0 h. The mean diameter of the beads could be controlled (approximately from 100 to 300 μm) by varying the agitation rate.     

Palladium Recovery from Dilute Effluents using Biopolymer‐Immobilized Extractant

Abstract

Cyanex 301‐immobilized material (prepared by immobilization into an alginate matrix) was tested for Pd sorption in 1 M HCl solutions with a special attention to sorption isotherms and uptake kinetics. This immobilized extractant had great affinity for Pd, as shown by the initial slope of the sorption isotherms. Sorption capacities as high as 150 mg Pd g^?1 were obtained in 1 M HCl solutions. However, kinetics was slow, compared to conventional resins. The main limiting step in the process is the diffusion of metal ions into the matrix. The influence of parameters such as HCl concentration, NaCl addition, presence of Pt (as a competitor metal) has been checked. It appeared that sorption performance of Cyanex 301‐immobilized material was hardly influenced by the addition of NaCl and by HCl concentration (below 2.5 M). The resin was remarkably selective for Pd, versus Pt, especially at 1 M HCl concentration. Loaded resins can be desorbed using thiourea solutions.     

Novel composite biopolymers of sodium alginate/natural rubber/coconut waste for adsorption of Pb(II) ions

A novel composite adsorbent in the form of beads for removal of Pb²⁺ from wastewater was prepared by blending a sodium alginate (NaAlg) solution, natural rubber (NR) latex, and coconut waste (cofiber). After being crosslinked by calcium chloride, the beads were highly stable, flexible, and easily used in the environment. The optimum composition of the beads with an average size of 1.1–1.2 mm was 4% NaAlg:NR latex (60% dry rubber content):cofiber at 50:1:0.72 and a 2%w/w CaCl₂ solution used for cross linking. The physico‐chemical properties of the beads were examined by the swelling ratio measurement, ATR‐FTIR, and SEM. The effects of the amount of cofiber, NR, and initial Pb²⁺ ions, the pH of the medium, the bead content, and the contact time, on the adsorption of Pb²⁺ were investigated. NR improved the water resistance and, hence, the stability of the beads. The cofiber increased the porosity and contact area and, hence, the efficiency of the composite beads to adsorb the Pb²⁺ up to 99.6%. The prepared beads are promising material to use for the effective and economical removal of Pb²⁺ from water. POLYM. COMPOS., 35:1013–1021, 2014. © 2013 Society of Plastics Engineers     

Characteristics of selective adsorption using D-phenylalanine imprinted terpolymer beads

A D-Phenylalanine (Phe) imprinted terpolymer, Polyacrylonitrile-Poly(acrylic acid)-Poly(acryl amide) (Poly(AN-AA-AAm)) bead was prepared by the wet-phase inversion method. Acrylamide (AAm) and acrylic acid (AA) were used as the functional monomer and acrylonitrile (AN) was used as a physical cross linker. The characteristics of selective adsorption by the D-Phe imprinted terpolymer beads were investigated at high concentrations of Phe racemate solution, 1 g Phe/L, and 10 g Phe/L. The adsorption selectivity of the D-Phe imprinted terpolymer beads prepared by anin-situ implanting method reached 0.82 and 0.8 at 1.0 g and 10 g Phe/L racemate solution, respectively, and almost all of the adsorbed D-Phe and about 43% of the adsorbed L-Phe were desorbed by 4% acetic acid. The uptake capacities of the terpolymer beads were maintained for several repeated batches.     

Optimization of L-Asparaginase Immobilization onto Calcium Alginate Beads

In this study, anti-leukemic enzyme L-asparaginase (E.C.3.5.1.1) from Escherichia coli ATCC 11303 was modified by the microencapsulation technique onto calcium alginate beads. Using response surface methodology (RSM), a three-level full factorial design, the values of concentration of sodium alginate, concentration of calcium chloride, and enzyme loading were investigated to obtain the highest residual L-asparaginase (L-ASNase) activity % (immobilized enzyme activity/free enzyme activity). The effects of the studied factors on immobilization were evaluated The predicted values by the model were close to the experimental values, indicating suitability of the model. The results presented that an increase in sodium alginate concentration increased the percent of residual activity of L-ASNase at any given calcium chloride concentration and the moderate amount of enzyme loading increased the percent residual activity. The optimal immobilization conditions were as follows: sodium alginate 1.98% (w/v), calcium chloride concentration 3.70% (w/v), and enzyme load 46.91% (v/v). The highest residual L-ASNase activity % obtained was 34.49%.     

Biodegradation of Phenol from Wastewater by Microorganism Immobilized in Bentonite and Carboxymethyl Cellulose Gel

This study presents a microbial process for phenol degradation in coking wastewater. The optimum immobilized condition of the strain for degrading phenol was determined through orthogonal experiment. The free and immobilized microorganisms were examined for their capabilities on degrading phenol. Results indicated that the optimum immobilized conditions were 20% microorganism suspension, 5% bentonite, 3% sodium carboxymethyl cellulose content, and 1 h of crosslinking time. The biodegradation rate was optimized at 35°C and 0.23 gmL^?1 of immobilized microorganism bead. The degrading rate for the immobilized microorganism bead was up to 95.96% at an initial phenol concentration of 100 mgL^?1; however, the immobilized microorganism considerably took more time (288 h) to reach 94.6% removal efficiency at a much higher concentration of 1000 mgL^?1. The batch experiment demonstrated that 94.50% of phenol was removed using the beads with the immobilized microorganism at an initial concentration of 500 mgL^?1. By contrast, only 24.60% and 33.88% of phenol were degraded using the gel beads without and with free microorganisms, respectively. The immobilized microorganism beads can used reused for up to nine cycles at the same initial phenol concentration (50 mgL^?1) and can be stored up to 40 d without loss of its degradation capacity.     

Immobilization of hybridoma cells in chitosan alginate beads

A new method for immobilizing hybridoma cells using chitosan-stabilized calcium alginate beads was developed. The ionotropic gelation of chitosan and calcium with alginate resulted in the formation of highly cross-linked, porous beads that were mechanically and chemically stable in phosphate buffered medium. Hybridomas entrapped in these beads were cultured semi-continuously using periodic medium exchange. Viable population densities in the order of 5 × I0⁷ cells/mL were attained within the beads and up to two-fold increases in volumetric monoclonal antibody (MAb) productivity over batch suspension cultures were observed. Oxygen mass transfer limitations within the chitosan-alginate beads were evaluated by considering biokinetics and diffusive transport. Model equations were developed and used to evaluate the effect of bead diameter on the contained cells. The predictions were consistent with experimental observations of maximum viable population densities attained in beads of various size.     

Spectral characterization of lysozyme adsorption on dye-affinity beads

Cibacron Blue F3GA-attached magnetic poly(2-hydroxyethyl methacrylate) [mPHEMA] beads were prepared by suspension polymerization of HEMA in the presence of magnetite (Fe₃O₄) nanopowder. Average diameter size of the mPHEMA beads was 150–200 μm. The characteristic functional groups of Cibacron Blue F3GA-attached mPHEMA beads were analyzed by Fourier transform infrared spectrometer (FTIR) and Raman scattering spectrometer. The lysozyme adsorption and desorption characteristics of Cibacron Blue F3GA-attached mPHEMA beads were also investigated using FTIR and Raman spectroscopic techniques. When the Raman spectrum of lysozyme adsorbed mPHEMA is evaluated characteristic Amide-I band appears at 1657 cm⁻¹. The intensity of this band decreases in the spectrum of lysozyme desorbed mPHEMA sample. When the characteristic bands of lysozyme adsorbed and desorbed mPHEMA samples are compared, the band intensities of desorbed sample are lower than those of lysozyme adsorbed sample except for the band appearing at 656 cm⁻¹ (Tyr vC S). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of interpenetrating polymer network gel beads for dye absorption

Preparation of interpenetrating polymer network (IPN) gel beads for dye absorption was carried out by using simultaneous crosslinking method. First, sodium alginate (SA), 3‐(methacrylamido) propyl trimethyl ammonium chloride (MAPTAC), and/or acrylamide (AM), K₂S₂O₈, and N,N′‐methylenebisacrylamide (MBAM) were mixed in aqueous solution. The beads were prepared using K₂S₂O₈ and MBAM as the initiator and crosslinking agent, respectively. Then, the solution was dropped into CaCl₂ solution mixed with N,N,N′,N′‐tetramethylethylenediamine (TMEDA). The former was used as the crosslinking agent of alginate and the latter was used as the accelerator for the polymerization of monomer in the alginate solution. The gel bead composed of only alginate was also prepared to compare the properties with IPN gel bead. The components in IPN gel bead were examined by FTIR analysis. The factors effecting the particle size of alginate and IPN gel beads were investigated. In alginate gel bead, the concentration of solution affected the particle size, whereas type of monomer affected the particle size of IPN gel bead. The IPN gel bead had smooth surface (from SEM results), different from the alginate bead. Alginate content caused the swelling behavior of dried IPN beads. Cationic dye was absorbed by crosslinked alginate gel bead. The absorption of reactive dye by IPN gel bead was a result of its cationic charge. The absorption density of IPN gel beads was the reciprocal of the absorbent dosage. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1585–1591, 2006     

Preparation of uniform calcium alginate gel beads by membrane emulsification coupled with internal gelation

With the objective of making calcium alginate gel beads with small and uniform size, membrane emulsification coupled with internal gelation was proposed. Spherical gel beads with mean size of about 50 μm, and even smaller ones in water, and with narrow size distribution were successfully obtained. Experimental studies focusing mainly on the effect of process parameters on bead properties were performed. The size of the beads was mainly dependent on the diameter of the membrane pores. High transmembrane pressure made for large gel beads with wide size distribution. Low sodium alginate concentration produced nonspherical beads, whereas a high concentration was unsuitable for the production of small beads with narrow distribution. Thus 1.5% w/v was enough. A high surfactant concentration favored the formation of small beads, but the adverse effect on mass transfer should be considered in this novel process. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 848–852, 2003     

固定化啤酒废酵母对Cd^2＋生物吸附性能的研究

选取啤酒废酵母作生物吸附剂，研究了啤酒酵母在固定化条件下，对重金属离子Cd^2＋的生物吸附性能。灭活的啤酒废酵母在适当的条件下，对Cd^2＋有较强的吸附作用，其吸附能力受酵母添加浓度、Cd^2＋浓度、pH值以及吸附时间的影响。结果表明，啤酒废酵母对Cd^2＋的最高吸附率达到79．82％、最高吸附量达到16．16mg·g^-1；吸附后，用1mol·L^-1的盐酸等进行解吸，解吸率最高达到了89．14％。