• 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 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 Korean Ceramic Society
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• v.38 no.2
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• pp.183-192
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• 2001

산업부산물을 이용하여 3CaO.3Al$_2$O$_3$.CaSO$_4$(C$_4$A$_3$S) 클링커를 합성하였다. 이때, 원료 물질은 산업부산물로 플라이 애쉬, 고로 수쇄 및 괴재슬래그를 $Al_2$O$_3$원으로 그리고 부산석고를 SO$_3$원으로 이용하였으며, CaO원으로 천연석회석을 사용하였다. 제조된 $C_4$A$_3$S 클링커를 CaSO$_4$, CaO를 배합하여 CSA계 팽창재를 제조하였으며, 일반 포틀랜드 시멘트(OPC)에 10 wt.% 첨가하여 수화 및 물성 특성을 조사하였다. 주요 수화생성상은 에트링자이트 및 수산화칼슘이었다. 수화시 에트링자이트의 생성으로 인해 팽창 및 경화체가 치밀화되어 건조수축이 감소되었고, 강도(압출, 인장, 휨)가 향상되었다.

• Polymer(Korea)
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• v.32 no.2
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• pp.178-182
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• 2008

Cellulose diacetate (CDA) and calcium carbonate ($CaCO_3$) biodegradable composites were prepared by melt mixing in a twin screw extruder and their physical properties were examined. In the melt processing, triacetine and epoxidized soybean oil were added to the composites as a plasticizer and lubricant, respectively. The optimal conditions for the preparation of the biodegradable composites were determined. Acetic acids ($CH_3COOH$) were made by pyrolysis acetyl group ($-OC (O)CH_3$) of CDA and TA in melt processing. Increasing the amount of $CaCO_3$ in the composites resulted in further enhancement of the $CH_3COOH$ absorption effects. The tensile strength and elongation were decreased, and Young's modulus and $T_g$ value increased with increasing amount of $CaCO_3$.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.286-294
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• 1989

Effects of cooking and drying methods on the quality of shrimp, Metapenaeus joyneri, were investigated. The cholesterol content of fresh shrimp was 81.4mg/100g of dry basis. It was $5{\sim}28%$ less in freeze dried shrimps as compared to hot air dried shrimps. The volatile basic nitrogen and trimethylamine contents of hot air dried shrimp was higher than those of freeze dried one, but total viable count of freeze dried shrimp was lower than that of hot air dried one. The color of cooked-shrimps was much brighter than uncooked-fresh shrimp. Freeze dried shrimp was lighter than hot air dried one. Total color difference $({\Delta}E)$, however, was opposite to its lightness. The mineral component of fresh shrimp was composed of calcium predominantly, followed by potassium and sodium, which were 96% of the total mineral contents. Cooking and drying methods did not affect the mineral content.

• 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.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.133-141
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• 2016

The physicochemical properties, antioxidant capacities, and sensory optimization of taro (Colocasia esculenta) under different aging conditions were investigated to develop black taro. Black taro was processed in three steps (steaming: $95{\pm}3^{\circ}C$ for 1 h; aging: 85, 90, $95^{\circ}C$ for 20, 40, and 60 h; drying: $60^{\circ}C$ for 24 h) and ground into a powder for all experiments. Black taro showed an increased crude fiber content and browning index compared to raw taro. Calcium oxalate contents, reducing sugar contents, moisture contents, and lightness values were decreased during the processing of taro. Improvements in total polyphenol content and antioxidant activity (DPPH, ABTS, FRAP) were observed in the black taro samples aged at higher temperature. Response surface methodology was used for sensory optimization, and the optimum aging conditions with the highest acceptance values were found to be $88.73^{\circ}C$ for 39.50 h for taste, and $88.82^{\circ}C$ for 42.60 h for overall acceptance.

• Korean journal of food and cookery science
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• v.18 no.1
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• pp.101-108
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• 2002

This study aimed to determine the effects of cooking treatment on chromaticity and 6 mineral contents (calcium, phosphorus, magnesium, iron, sodium and potassium) in sea mustards. Four samples of natural and cultured sea mustard were used for the experiments. Each sample was treated with four cooking methods (A: soaked in water, B: boiled in hot water, C: saute and boiled in hot water, D: seasoned with vinegar). The L, a and b values were the highest on boiling, and the lowest on seasoning with vinegar. The a value of cultured sea mustard was higher than the natural one by cooking. Moisture was highest boiling and were ordered as saute and boiling, soaking and seasoning with vinegar. Calcium, iron, magnesium and phosphorus contents were remarkably decreased by seasoning with vinegar. Boiling treatment made less decrease than saut and boiling in these mineral contents. The solubilities of mineral in soup water were recognized therefore, it indicated that soup water was a good source of minerals as it applies to cooking, from the view point of science of cookery. Sodium and potassium contents decreased significantly more at 68% and 85% of total content on basic soaking treatment. Ca/P ratio was about 1∼3 : 1 in cultured sea mustard and 3∼4 : 1 levels in natural one.

• 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.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.529-534
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• 2008

The normal shell and the regenerated oyster shell, Crassostrea gigas, are separated according to the characteristics of inner shell morphology. To study characteristics of chitin obtained from the regenerated shell, chitin prepared by acid and alkali process is analyzed by FT-IR (Fourier transform infrared spectrometer) and XRD (X-ray Diffractometer). The content of insoluble protein in the normal shell was more than doubled as compared with that in the regenerated shell. A comparison of secondary structure of the normal shell and the regenerated shell revealed that the content of random of the regenerated shell was above 47%, indicating an amount in the structural unordered state. Through amino acid composition analysis and secondary protein structure of soluble protein isolated from the normal shell and the regenerated shell, it was found that there are differences in biomineralization strategy of the regenerated shell as compared to the normal shell. The relatively low hardness of the regenerated shell is caused by the change of amino acid composition and ordered secondary protein structure as compared to hardness of the normal shell.