• Applied Biological Chemistry
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• v.30 no.1
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• pp.77-87
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• 1987

The mutant with high productivity, X. malvacearum SNUF 560-6, was acquired from the X. malvacearum SNUF 560 with low productivity by UV-light irradiation. It was preserved is lyophilized stock culture and it was transferred to PDA slant to maintain viability fortnightly. Fermentations were started by retransfering to MY agar slant from PDA stok culture. The experiments for optimal xanthan gum production were studied in a chemically defined medium. Of the carbon and nitrogen sources tested, 0.4% sucrose medium and 10mM glutamic acid medium yielded the highest xanthan gun production respectively. The addition of 10g/l succinic acid stimulated xanthan gum production. Also 65mM $PO_4\;^{-3}\;(12.6g/l\;KH_2PO_4)$ was effective on xanthan gum production. Finally, medium 1 and medium 2 which have high xanthan gum production potencies were achieved in this stud. The components of medium 1 and medium 2 were as follows: Medium 1 : sucrose 40g/l glutamate 10mM $PO_4\;^{-3}\;54mM\;(KH_2PO_4\;12.65g/l)$ Citrate 2g/l $MgSO_4{\cdot}7H_2O\;0.2g/l$ $H_3BO_3\;0.005/l$ ZnO 0.006/l $FeCl_2{\cdot}6H_2O\;0.0024g/l$ $CaCO_3\;0.02g/l$ Medium 2 : $Sucrose\;40g/l\;(NH_4)_2SO_4\;2g/l$ $PO_4\;^{-3}\;65mM\;(KH_2PO_4\;12.65g/l)$ Succinate 10g/l $MgSO_4{\cdot}7H_2O\;0.02g/l$ $H_3BO_3\;0.06g/l$ ZnO 0.006g/l $FeCl_2{\cdot}6H_2O\;0.0024g/l$ $CaCO_3\;0.02g/l$.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.939-943
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• 1999

Recently there has been an explosion of interest in the topic of biodegradable polymers for medical applications. In this study, films were prepared by solution casting method using natural polymers (xanthan, locust bean, guar gum, chitosan and algin) as biomaterials. Biocompatibility of films prepared from natural polymer as a skin implant was evaluated. These biodegradable films were subcutaneously implanted in the back of rats and their biodegradability was investigated by the evaluation of changes in structure, film weight and hematology as a function of time for the biotransformation. The result of rats test showed that locust bean and guar gum induced some suspects of non-biocompatibility in the tissue by foreign body reaction 24 and 48 hrs after implantation. These results showed the potential of partial biodegradable films prepared from natural polymer for ideal skin biomaterials at short period.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.153-153
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• 2005

• The Microorganisms and Industry
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• v.18 no.1
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• pp.23-27
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• 1992

전분이 함유된 플ㄹ스틱 및 광분해성 플라스틱은 제외하고 순수하게 생분해되는 생분해성 고분자의 시장은 세계적으로 년간 140만톤으로 추정되고 있다. 이 중에서 생물공학과 직접적으로 관계가 있는 것은 polylactide계 polymer의 원료가 되는 lactic acid, pullulan과 같은 polysaccharide 그리고 PHA와 같은 polyester등으로서 본고에서는 PHA(polyhydroxyalkanoate)를 중심으로 생산공정이 어떻게 개발되어 오고 있는가 간단히 고찰하고자 한다. 이러한 생산공정의 원리는 pullulan 및 xanthan gum과 같은 타 생물고분자의 경우에도 유사하게 적용될 수 있다.

• Proceedings of the Korean Society of Rheology Conference
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• 2006.06a
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• pp.95-99
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• 2006

• Proceedings of the Korean Society of Rheology Conference
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• 2006.06a
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• pp.119-122
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• 2006

• Proceedings of the Korean Society of Rheology Conference
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• 2006.06a
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• pp.123-126
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• 2006

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.09a
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• pp.40-40
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• 2019

• Proceedings of the Korean Society of Crop Science Conference
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• 2020.11a
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• pp.94-94
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• 2020

• Journal of Korean Society on Water Environment
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• v.36 no.3
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• pp.185-193
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• 2020

Bimodal flocculation describes the aggregation and breakage processes of the flocculi (or primary particles) and the flocs in the water environment. Bimodal flocculation causes bimodal size distribution with the two separate peaks of the flocculi and the flocs. Extracellular polymeric substances and ionic species common in the water environment increase the occurrence of bimodal flocculation and flocculi-floc size distribution, under the flocculation mechanisms of electrostatic attraction and polymeric bridging. This study investigated bimodal flocculation and flocculi-floc size distribution, with respect to the extracellular polymeric substance concentration and ionic strength in the kaolinite-containing suspension. The batch flocculation tests comprising 0.12 g/L of kaolinite showed that the highest flocculation potential occurred at the lowest xanthan gum (as extracellular polymeric substances) concentration, under all the ionic strengths of 0.001, 0.01, and 0.1 M NaCl. Also, it was important to note that the higher ionic strength resulted in the higher flocculation potential, at all the xanthan gum concentrations. The bimodal flocculation and flocculi-floc size distribution became apparent in the experimental conditions, which had low and intermediate flocculation potential. Besides the polymeric bridging flocculation, steric stabilization increased the flocculi mass fraction against the floc mass fraction, thereby developing the bimodal size distribution.