• Environmental Engineering Research
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• v.15 no.3
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• pp.149-156
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• 2010

The objective of this study was to investigate microbial removal using layered double hydroxides (LDHs) and iron (hydr)oxides (IHs) immobilized onto granular media. Column experiments were performed using calcium alginate beads (CA beads), LDHs entrapped in CA beads (LDH beads), quartz sand (QS), iron hydroxide-coated sand (IHCS) and hematite-coated sand (HCS). Microbial breakthrough curves were obtained by monitoring the effluent, with the percentage of microbial removal and collector efficiency then quantified from these curves. The results showed that the LDH beads were ineffective for the removal of the negatively-charged microbes (27.7% at 1 mM solution), even though the positively-charged LDHs were contained on the beads. The above could be related to the immobilization method, where LDH powders were immobilized inside CA beads with nano-sized pores (about 10 nm); therefore, micro-sized microbes (E. coli = 1.21 ${\mu}m$) could not diffuse through the pores to come into contact with the LDHs in the beads, but adhere only to the exterior surface of the beads via polymeric interaction. IHCS was the most effective in the microbial removal (86.0% at 1 mM solution), which could be attributed to the iron hydroxide coated onto the exterior surface of QS had a positive surface charge and, therefore, effectively attracted the negatively-charged microbes via electrostatic interactions. Meanwhile, HCS was far less effective (35.6% at 1 mM solution) than IHCS because the hematite coated onto the external surface of QS is a crystallized iron oxide with a negative surface charge. This study has helped to improve our knowledge on the potential application of functional granular media for microbial removal.

• Food Science and Preservation
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• v.6 no.2
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• pp.221-227
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• 1999

The immobilized culture system of Saccharomyces cerevisiae was examined to improve the efficiency of vinegar production from persimmon juice. Optimum concentration of Na-alginate for the immobilization was 2%. When the 1eakage of yeast from get beads was checked by turbidity of culture medium with varying concentration of Na-alginate from 1 to 4%, turbidity of culture medium increased from 8 hrs of cultivation with 1% Na-alginate concentration showing optical density of 0.82 at 20 hrs. However, the increase in turbidity of culture medium was slow with 2-4% Na-alginate showing optical density of 0.55-0.58 at 20 hrs. Microscopical analysis of gel matrix showed that the immobilized yeast was grown well regardless of Na-alginate concentration. Optimum size of gel bead and amount of inoculation were 2-3 m and 33mg, respectively. For ethanol production aerobic cultivation for 121hrs using cohen plug followed by anaerobic cultivation using silicon plug equipped with a check valve was the most effective.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.36-40
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• 2004

It is now widely accepted that immobilized microbial cells can overcome some of the problems associated with microbial survival stability, efficacy, storage, transportation and ease of application in agricultural environments. Pantoea agglomerans, a phosphate solubilizing bacterium, was immobilized in alginate, agar and gelatin carriers. All the three immobilfized carriers with bacterial cells of P. agglomerans were compared for solubilization of tricalcium phosphate in pure liquid cultures. While alginate beads were tested for phosphate solubilization on alternate days up to five days, agar beads and gelatin cubes were subjected for one time phosphate solubilization analysis after seven days. Both alginate and agar immobilized cells of P. agglomerans exhibited higher efficiency in increasing the solubilizaliun of tricalcium phosphate than gelatin immobilized cells. The culture filtrate of alginate bead inoculation treatment registered a rapid increase in soluble phosphate concentration upon incubation. A corresponding decrease in the pH of the medium was also observed in all the treatments.

• Culinary science and hospitality research
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• v.18 no.4
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• pp.209-221
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• 2012

The purpose of this study is to apply molecular gastronomy and its spherification methodology to persimmon desserts. We prepared persimmon calcium alginate beads and investigated physical and sensory characteristics of beads according to the different concentration of calcium chloride(0.5, 0.75, 1.0%) and reaction time(2, 4, 6, 8, 10 min). Lightness and yellowness were decreased significantly as both calcium chloride concentration and reaction time increased. However, redness was increased significantly as the concentration of calcium chloride and reaction time increased. Hardness, springiness, chewiness, cohesiveness, and resilience except for adhesiveness tended to increase as the concentration of calcium chloride and reaction time increased. The thickness of beads also increased as the concentration of calcium chloride and reaction time increased. Quantitative descriptive analysis showed that voluminosity, springiness, hardness, chewiness, and residue tended to increase as the concentration of calcium chloride increased. Overall acceptability reached a peak at the persimmon bead containing 0.5% calcium chloride. The result of this study showed that the concentration of calcium chloride and reaction time influenced the overall characteristics of calcium alginate beads.

• Molecules and Cells
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• v.41 no.12
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• pp.1016-1023
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• 2018

Regenerative orthopedics needs significant devices to transplant human stem cells into damaged tissue and encourage automatic growth into replacements suitable for the human skeleton. Soft biomaterials have similarities in mechanical, structural and architectural properties to natural extracellular matrix (ECM), but often lack essential ECM molecules and signals. Here we engineer mineralized polysaccharide beads to transform MSCs into osteogenic cells and osteoid tissue for transplantation. Bone morphogenic proteins (BMP-2) and indispensable ECM proteins both directed differentiation inside alginate beads. Laminin and collagen IV basement membrane matrix proteins fixed and organized MSCs onto the alginate matrix, and BMP-2 drove differentiation, osteoid tissue self-assembly, and small-scale mineralization. Augmentation of alginate is necessary, and we showed that a few rationally selected small proteins from the basement membrane (BM) compartment of the ECM were sufficient to up-regulate cell expression of Runx-2 and osteocalcin for osteoid formation, resulting in Alizarin red-positive mineral nodules. More significantly, nested BMP-2 and BM beads added to a non-union skull defect, self-generated osteoid expressing osteopontin (OPN) and osteocalcin (OCN) in a chain along the defect, at only four weeks, establishing a framework for complete regeneration expected in 6 and 12 weeks. Alginate beads are beneficial surgical devices for transplanting therapeutic cells in programmed (by the ECM components and alginate-chitosan properties) reaction environments ideal for promoting bone tissue.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.390-397
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• 1991

Ethanol production by calcium alginate-immobilized baker's yeast (Saccharor/tyces cereviszae) was studied in the batch fermentation using glucose medium as a feed. Immobilied cells were stable between $30^{\circ}C$ and $40^{\circ}C$ whereas free cells were stable between $30^{\circ}C$ and $37^{\circ}C$ The beads were showed constant ethanol productivity during 720 hours (30 days) over. Fermentation characteristics of immobilized baker's yeast were examined changing the initial glucose concentration of broth in fermentation. Initial glucose concentrations employed were 50, 100, 150 and 200 g/l, respectively. In 15% gucose medium, maximum specific growth rate, maximum ethanol yield and ethanol concentration were observed as 0.092 $h^{-1}$, 0.45, 67.5 g/l, respectively.

• KSBB Journal
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• v.4 no.2
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• pp.110-117
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• 1989

The fiffusion characteristics of substrate of varing biomass concentrations into and from Ca- alginate gel beads in well-stirred solutions were investigated. Ca-alginate gel beads were immobilized by Zymomonas mobilis or free from cells. The values of the diffusion coefficient of substrate were calculated by means of the method of Least squares and Random pore model. Reaction rates are expressed by the Michaelis-Menten type equation, and the results are compared with experimental data. Intraparticle effective diffusivity of substrate resistance on reaction by using immobilized Z.mobilis entrapped by Ca-alginated gel seemed to be restricted by cell density. The experimental data also indicated relationship between the effective diffusivity and the cell concentration used in the gel preparation.

• Journal of Korean Society on Water Environment
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• v.38 no.4
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• pp.171-176
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• 2022

Recently, an autotrophic single-stage nitrogen removal (ASSNR) process based on the anaerobic ammonium oxidation (ANAMMOX) reaction has been proven as an economical ammonia treatment. It is highly evident that double-layered gel beads are a promising alternative to the natural biofilm for ASSNR because of the high mechanical strength of poly(vinyl alcohol) (PVA)/alginate structure and efficient protection of ANAMMOX bacteria from dissolved oxygen (DO) due to the thick outer layer. However, the thick outer layer results in severe mass transport limitation and consequent lowered bacterial activity. Therefore, the effects of the thickness of the outer layer on the overall reaction rate were tested in the biofilm model using AQUASIM for ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB) and ANAMMOX bacteria. A thickness of 0.5~1.0 mm is preferred for the maximum total nitrogen (TN) removal. In addition, a DO of 0.5 mg/L resulted in the best total nitrogen removal. A higher DO induces NOB activity and consequent lower TN removal efficiency. The optimal density of AO B and NO B density was 1~10% for a 10% ANAMMOX bacterial in the double-layered PVA/alginate gel beads. The real effects of operating parameters of the thickness of the outer layer, DO and concentrations of biomass balance should be intensively investigated in the controlled experiments in batch and continuous modes.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.132-139
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• 1999

A cell-entrapment technique using compressed air was applied to Bifidobacterium longum KCTC 3128 for the improvement of bifidobacteria viability. The main cell-entrapment matrix used was alginate, and viability improvement of the B. longum entrapped in alginate lattices was monitored along with the effects of other additional biopolymers. A prerequisite for acquiring consistent results was the uniformity of bead size and cell distribution which was achieved by using compressed air and mixing the cell suspension with sterilized alginate powder, respectively. The viability losses of the B. longum entrapped in alginate beads in the presence of three different substances logarithmically increased in relation to the reaction time, and proportionately decreased with an increased alginate concentration and bead diameter. The strongest improvement in B. longum viability was exhibited with a bead containing 3％ alginate and 0.15％ xanthan gum.

• Carbon letters
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• v.11 no.2
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• pp.117-121
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• 2010

The composites of alginate, carbon nanotube, and iron(III) oxide were prepared for the removal of heavy metal in aqueous pollutant. Both alginate and carbon nanotube were used as an adsorbent material and iron oxide was introduced for the easy recovery after removal of heavy metal to eliminate the secondary pollution. The morphology of composites was investigated by FE-SEM showing the carbon nanotubes coated with alginate and the iron oxide dispersed in the alginate matrix. The ferromagnetic properties of composites were shown by including iron(III) oxide additive. The copper ion removal was investigated with ICP AES. The copper ion removal efficiency increased greatly over 60% by using alginate-carbon nanotube composites.