• The Korean Journal of Malacology
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• v.26 no.1
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• pp.1-18
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• 2010

Biological organisms produce organic-inorganic nanocomposite composites that are hierarchically organized in composition and microstructure, containing both inorganic and organic components in complicated mixtures. The process related to the generation and regeneration of organic-inorganic complex in nature is called biomineralization process. Understanding how the process operates in a biological environment is a valuable guide to the synthesis of novel advanced material and developing important industrial processes. Like the mechanism of organisms, mollusks were also synthesized from interaction between organic matrices and minerals and their morphology was designed through biomineralization. In this study, shell formation has been studied as a bio-model and the application of biomimetics based on biomineralization is focused.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.598-606
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• 2013

This study was performed to determine whether biomineralization microbes were actively present underneath landfill cover soil producing biocalcification. From this, various types of microbes were observed. Among them, two species were dominantly found; Bacillus megaterium and Alkaliphilus metalliredigens that were known as biominerlization bacteria. With those microbes, $CO_2$ was more highly consumed than without bacteria. In response, the calcium carbonate mineral was produced at 30% (wt) greater than that of the control. At the same time, TG-DTA was successfully used for quantification of $CO_2$ consumed forming calcium carbonate minerals resulting from biocalcification. It was decided that the presence of solidified sewage sludge cake utilized as a cover soil in the landfill could efficiently contribute to possible media adaptably and naturally sequestering $CO_2$ producing from the landfill.

• Journal of the Mineralogical Society of Korea
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• v.16 no.2
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• pp.171-180
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• 2003

The objective of this study is to investigate biogeochemical processes to sequester $CO_2$and metals utilizing metal-rich fly ash (MRFA). Microbial conversion of $CO_2$into sparingly soluble carbonate minerals has been studied using MRFA under different $pCO_2$and different bicarbonate concentrations. Scaling from test tube to fermentation vessels (up to 4-L) using metal-reducing bacteria and MRFA has proved successful at sequestering carbon dioxide and metals. $CO_2$sequestration via precipitation processes using MRFA may complement the process of $CO_2$capture from fossil fuel plants while potentially stabilizing fly ash wastes.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.812-820
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• 2011

This study was conducted to characterize $CO_2$ biomineralization on several minerals (i.e., CaO, MgO, $SiO_2$) by bottle test in an aqueous solution and solidified sludge using different aerobic bacterial strains like Bacillus megaterium and Bacillus pasteurii by batch test. These bacteria promote the formation of microenvironments that facilitate the precipitation of mineral phases that were unsaturated in the bulk solution. For one type of mineral solely amended, the $CO_2$ was reduced at the highest of 4.0 mmol for MgO while it was not that much lower for CaO and $SiO_2$ showing 1.1 and 0.3 mmol $CO_2$2, respectively. For two types of minerals simultaneously amended, the $CO_2$ was reduced at the greater extent for both Ca + Mg and Mg + Si showing 2.7 and 2.3 mmol, respectively whereas it was less for Ca + Si at 1.8 mmol. For solidified sludge, the $CO_2$ reduction rate changed depending on the volume of solidified sludge placed in the medium and the input $CO_2$ concentration.. The reduction rate of $CO_2$ was increased with increasing the volume of solidified sludge. Results of XRD analysis indicate that $CaCO_3$ (Calcite) was dominantly formed among others (e.g., Aragonite, Dolomite). SEM analysis showed that the sample with Bacillus pasteurii, could more form minerals rather than control. As demonstrated in this study, $CO_2$ would be effectively sequestered in biomineralization process.

• Journal of the Mineralogical Society of Korea
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• v.32 no.1
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• pp.63-69
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• 2019

The oxidation states of structural Fe in minerals reflect the paleo-depositional redox conditions for the biologically or abiotically induced mineral formation. Particularly, nano-scale analysis using high-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) is necessary to identify evidence for the microbial role in the biomineralization. HRTEM-EELS analysis of oxidation states of structural Fe and carbon bonding structure differentiate biological factors in mineralization by mapping the distribution of Fe(II)/Fe(III) and source of organic C. HRTEM-EELS technique provides geomicrobiologists with the direct nano-scale evidence of microbe-mineral interaction.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.179-191
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• 2013

This study was conducted to comparatively assess quantitative indicating factor for biomineralization characterizing $CO_2$ mineralization on three type of minerals (i.e., $CaCl_2$, $MgCl_2$, $CaCl_2-MgCl_2$) in an aqueous solution amended with Bacillus pasteurii or indigenous microorganisms for a S landfill cover soil. For given three types of minerals, $NH_4{^+}$ (urease activity) was released at the highest of 88 mg/L for $MgCl_2$, then 85 mg/L for $CaCl_2$, and the lowest of 42 mg/L for $CaCl_2-MgCl_2$. $CO_2$ gas in the head space was completely removed after 12, 12, and 24 hr for $CaCl_2$, $MgCl_2$ and $CaCl_2-MgCl_2$, respectively. $Ca^{2+}$ concentration in $CaCl_2$ solution was the quickest and the greatest decreased 92% for 12 hr whereas that in $CaCl_2-MgCl_2$ solution was lower at 85% for 36 hr. $Mg^{2+}$ concentration in $MgCl_2$ was more efficiently decreased at 46% for 48 hr than that of $CaCl_2-MgCl_2$ solution of 38.5% for 72 hr. Regardless of types of minerals or their concentration, pH was changed from 5.5 to 9 by biomineralization being progressed. Microbial activity ($OD_{600}$) was also changed from 0 to 0.6. SEM images indicated that spheroidal and trapezoid shape crystal were formed, which were identified as of $CaCO_3$ (Calcite) and $MgCO_3$ (Magnesite) by X-ray diffraction. In the long run, $NH_4{^+}$ (urease activity), $CO_2$ gas, $OD_{600}$, pH, $Ca^{2+}$ and $Mg^{2+}$ would be suitable for reasonable indicating factor in order to assess the degree of biomineralization efficiency.

• Journal of Periodontal and Implant Science
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• v.36 no.3
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• pp.601-611
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• 2006

임프란트 식립을 필요로 하는 환자의 수평적 치조제 결손의 증대를 위해 골유도재생술과 병용한 bioactive glass (BG) $(Biogran^{(R)})$ 이식의 골재생 양상을 각기 다른 치유기간을 부여한 4명의 환자에서 평가하였다. 6, 8, 10, 18개월의 치유기간 후 임프란트 식립부위에서 조직절편을 채득하여 골재생을 조직계측학적으로 평가하였다. 임프란트 식립을 위한 surgical reentry시 모든 이식부위는 임상적으로 명확한 수평적 치조제 폭경의 증가를 관찰할 수 있었다. 하지만 조직학적 분석결과 BG는 불량한 골전도성을 나타내었다. 6, 8개월의 치유기간후, 이식부위에서 신생골이 거의 관찰되지 않았으며(2.5%이하), 이식부와 기존 골의 경계부위에서 BG particle에 대한 신생골 성장과 결합양상 또는 관찰할 수 없었다. 10개월의 치유기간후 기존 골조직으로부터 성장한 신생골의 BG particle과의 직접적인 접촉양상을 일부 관찰할 수 있었다. 이식부는 13.2%의 광물화된 신생골조직을 보였고, 대부분의 BG particle은 결체조직으로 둘러싸여 있었다. 18개월의 치유기간이 부여된 환자의 조직절편에서 신생골은 이식부의 10.7%를 차지하여 비교적 낮은 신생골 형성양을 나타내었고, 이식부에 존재하는 잔존BG particle은 대부분은 결체조직으로, 일부분에서 광물화된 골조직으로 둘러싸여 있었다. 6, 8, 10, 18개월에서 잔존 BG particle양은 전체 이식부 면적에 대해서 각기 22.3%, 26.5%, 30.7%, 18.7%로 나타났다. 본 증례보고는 비록 한정적인 4명의 환자에서의 조직계측학적 평가결과이지만, 수평적 치조제 결손의 증대를 위해 골유도재생술과 병용한 bioactive glass이식은 불량한 골전도성으로 인해 효과적인 골재생을 위한 이식재로서는 적절하지 않을 수 있음을 나타낸다.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.431-439
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• 2014

The purposes of this research were to investigate the enrichment of metal-reducing bacteria from KURT groundwater and the identification of the microbial diversity by 16S rRNA as well as to examine microbial Fe(III)/Mn(IV) reduction and to analyze morphological features of interactions between microbes and precipitates and their mineralogical composition. To cultivate metal-reducing bacteria from groundwater sampled at the KURT in S. Korea, different electron donors such as glucose, acetate, lactate, formate, pyruvate and Fe(III)-citrate as an electron accepter were added into growth media. The enriched culture was identified by 16S rRNA gene sequence analysis for the diversity of microbial species. The effect of electron donors (i.e., glucose, acetate, lactate, formate, pyruvate) and electron acceptors (i.e., akaganeite, manganese oxide) on microbial iron/manganese reduction and biomineralization were examined using the 1st enriched culture, respectively. SEM, EDX, and XRD analyses were used to determine morphological features, chemical composition of microbes and mineralogical characteristics of the iron and manganese minerals. Based on 16S rRNA gene analysis, the four species, Fusibacter, Desulfuromonas, Actinobacteria, Pseudomonas sp., from KURT groundwater were identified as anaerobic metal reducers and these microbes precipitated metals outside of cells in common. XRD and EDX analyses showed that Fe(III)-containing mineral, akaganeite (${\beta}$-FeOOH), reduced into Fe(II)/Fe(III)-containing magnetite ($Fe_3O_4$) and Mn(IV)-containing manganese oxide (${\lambda}-MnO_2$) into Mn(II)-containing rhodochrosite ($MnCO_3$) by the microbes. These results implicate that microbial metabolism and respiratory activities under anaerobic condition result in reduction and biomineralization of iron and manganese minerals. Therefore, the microbes cultivated from groundwater in KURT might play a major role to reduce various metals from highly toxic, mobile to less toxic, immobile.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.205-209
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• 2019

The exquisite structure and attractive biological properties of biominerals have great potential and increased interest for use in a wide range of medical and industrial applications. Calcium carbonate biomineralization, mainly controlled by shell matrix proteins, has been used as a representative model to understand the biomineralization mechanism. In this study, in vitro calcium carbonate crystallization was carried out under room temperature and atmospheric pressure using recombinant shell matrix protein GRP_BA and artificial shell matrix protein GG1234. Both proteins inhibited the growth of typical rhombohedral calcite crystals in the calcium carbonate crystallization using $CaCl_2$ solution and $(NH_4)_2CO_3$ vapor, and spherulitic calcite crystals with rosette-like structures were synthesized in both the presence of GRP_BA and GG1234. These results might be caused by the properties of block-like domain structure and intrinsically disordered proteins. We expect that this study can contribute to enhance understanding of the calcium carbonate biomineralization controlled by shell matrix proteins.

• Journal of the Mineralogical Society of Korea
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• v.31 no.2
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• pp.113-121
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• 2018

Baekasan Acheon cave located in Hwasun-gun, Jeollanam-do is a natural limestone cave only found in this province. In this study, the mineralogical and geochemical characteristics of speleothems collected from Baekasan Acheon cave were identified and the capability of carbonate mineral formation by aerobic microorganisms enriched from the cave and the mineralogical and geochemical characteristics of carbonate minerals formed by the microorganisms were investigated. The samples of sediments (clay) and speleothems (shelfstone and cave coral) were collected at three sites in the cave. The samples of shelfstone and cave coral were identified mainly as carbonate mineral, Mg-rich calcite, and clay minerals were composed of quartz, muscovite, and vermiculite by X-ray diffraction (XRD) analysis. To cultivate the carbonate forming microorganisms, parts of the sediment and speleothems were placed in D-1 medium containing urea, respectively, and the growth of microorganisms was observed under the aerobic condition at room temperature. The capability of carbonate mineralization of the cultured Baekasan Acheon cave microorganisms was examined through adding 1% (v/v) of the cultured microorganisms and calcium sources, Ca-acetate or Ca-lactate, into the D-1 medium. XRD analysis showed that the microorganisms cultured in cave deposits formed calcium carbonate ($CaCO_3$) under all conditions, and these microbial carbonate minerals included calcite and vaterite. The morphological characteristics and chemical composition of biologically formed minerals were observed by SEM-EDS showed various crystal forms such as rhomboid, spherical, perforated surface with Ca, C, and O of major chemical components. The existence of such microorganisms in the cave can contribute the formation of carbonate minerals, and it is likely to affect the geochemical cycles of carbon and calcium in the cave.