• Journal of Environmental Health Sciences
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• v.17 no.1
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• pp.120-128
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• 1991

Saccharomyces cerevisiae was immobilized by incubating iron oxides with calcium alginate, and by polyacrylamide entrapment to use repeatedly for the conversion of glucose to ethanol. Magnetic and non-magnetic immobilized yeast and polyacrylamide immobilized yeast were compared with the native yeast a batch-fermentation of ethanol from glucose. Three kinds of immobilized yeast tended almost identically, having ethanol productivity as well as the final yield about the same to what was found for the native yeast. The long-term operational stability of three kinds of immobilized yeast were significant difference according as immobilized yeast activation or non-activation before ethanol fermentation. In the non-activation they lost their activity of fermentation rapidly in the beginning stage an slower at a later stage. On the other hand, in the activation with nutrient media, their activities were increased to some extent and stable in the later stage. The cell count of three kinds of immobilized yeast after activiation by incubating nutrient media, increased by a factor of about 45 to 48, whereas the fermenting capacity increased by a factor of 174 to 178. In the prearation of immobilized biocatalysts, magnetic matter does not seem to have any adverse affect on the properties of the microorganism. The immobilized biocatalysts by utilizing magnetic matter have some advantages, especially in application of viscous media or insoluble particle-containing media, for this work was linked with microbial utilization of environmental wastes and elimination of envirnmental pollutant.

• Journal of Soil and Groundwater Environment
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• v.20 no.3
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• pp.83-91
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• 2015

Mine soil contamination by high levels of metal ions that prevents the successful vegetation poses a serious problem. In the study presented here, we used the microbial biocatalyst of urease producing bacterium Sporosarcina pasteurii or plant extract based BioNeutro-GEM (BNG) agent. The ability of the biocatalysts to bioremediate contaminated soil from abandoned mine was examined by solid-state composting vegetation under field conditions. Treatment of mine soil with the 2 biocatalysts for 5 months resulted in pH increase and electric conductivity reduction compared to untreated control. Further analyses revealed that the microbial catalysts also promoted the root and shoot growth to the untreated control during the vegetation treatments. After the Sporosarcina pasteurii or plant extract based BNG treatment, the microbial community change was monitored by culture-independent pyrosequencing. These results demonstrate that the microbial biocatalysts could potentially be used in the soil bioremediation from mine-impacted area.

• Proceedings of the Microbiological Society of Korea Conference
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• 2003.05a
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• pp.134-135
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• 2003

• 한국전기화학회:학술대회논문집
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• 2004.04a
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• pp.28-28
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• 2004

• KSBB Journal
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• v.8 no.5
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• pp.417-423
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• 1993

The effect of moisture content of biocatalyst on the performance of a gas phase continuous bioreactor was investigated along with study on the mass transfer limitation. The biocatalysts whose moisture contents are 46.2% and 37.2%, respectively were prepared by immobilization of alcohol oxidase on Amberlite IRA-400, following by slow dehydration method, and packed into a column. Relative production rate (RPR), acetaldehyde composition ($X_p$) and conversion (X) of biocatalysts (37.2%) are better than those of biocatalysls (46.2%), and it was considered that these are attributed to the mass transfer enhancement in the gas phase compared with the aqueous phase.

• BMB Reports
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• v.44 no.2
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• pp.77-86
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• 2011

Over the years, nanostructures have been developed to enable to support enzyme usability to obtain highly selective and efficient biocatalysts for catalyzing processes under various conditions. This review summarizes recent developments in the nanostructures for enzyme supporters, typically those formed with various inorganic materials. To improve enzyme attachment, the surface of nanomaterials is properly modified to express specific functional groups. Various materials and nanostructures can be applied to improve both enzyme activity and stability. The merits of the incorporation of enzymes in inorganic nanomaterials and unprecedented opportunities for enhanced enzyme properties are discussed. Finally, the limitations encountered with nanomaterial-based enzyme immobilization are discussed together with the future prospects of such systems.

• Journal of Microbiology
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• v.43 no.2
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• pp.196-203
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• 2005

Here, we attempted to evaluate the activity of artificially transconjugated multiple plasmids in 'designer biocatalysts' for the bioremediation of cocontaminated sites under nonselective conditions. We observed profound losses in the percent survivals of artificially transconjugated plasmid activity ($66 - 78\%$ loss immediately after freeze-drying, $99.45 - 99.88\%$ loss by the end of 6 months storage) in reconstituted Pseudomonas sp. KM12TC. Such unpredictable high losses of this particular plasmid appeared to clearly be a deleterious effect. However, even after 6 months of storage, the cells remained able to degrade $95\%$ of phenol within 9 days, and the full effiux of$^%${73} As, as compared to that of the non-freeze-dried cells, was successfully achieved 4 to 9 days later. These results indicate that 'stable designer biocatalysts' can remain viable, even after freeze-drying and 6 months of storage.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2004.06a
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• pp.203-208
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• 2004

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.207-210
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• 2000

As a typical example of the screening for a microbial biocatalyst from nature, isolation of nitrilesynthesizing microorganisms, characterization of a new enzyme aldoxime dehydratase, and its function in the aldoxime-nitrile pathway are introduced. Catalytic properties of some of our enzymes were improved through a direct evolutionary approach.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1257-1263
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• 2011

This paper is dedicated to the study on the external and internal mass transfers of glucose for succinic acid fermentation under substrate and product inhibitions using a bioreactor with stirred bed of immobilized Actinobacillus succinogenes cells. By means of the substrate mass balance for a single particle of biocatalysts, considering the kinetic model adapted for both inhibitory effects, specific mathematical models were developed for describing the profiles of the substrate concentration in the outer and inner regions of biocatalysts and for estimating the substrate mass flows in the liquid boundary layer surrounding the particle and inside the particle. The values of the mass flows were significantly influenced by the internal diffusion velocity and rate of the biochemical reaction of substrate consumption. These cumulated influences led to the appearance of a biological inactive region near the particle center, its magnitude varying from 0 to 5.3% of the overall volume of particles.