• Microbiology and Biotechnology Letters
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• v.37 no.1
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• pp.62-68
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• 2009

The culture conditions to maximize the production of laccase (EC 1.10.3.2) from Fomitopsis pinicola mycelia were investigated. Among the tested media for the enzyme production, mushroom complete medium (MCM ; 2% dextrose, 0.2% peptone, 0.2% yeast extract, 0.05% $KH_2PO_4$, and 0.05% $MgSO_4{\cdot}7H_2O$) showed the highest activity of the enzyme. To optimize the culture condition for the laccase activity, influence of various carbon and nitrogen sources was investigated in MCM. Among various carbon and nitrogen sources, 2% glucose and 0.4% peptone showed the highest production of the enzyme, respectively. For the phosphorus and inorganic source, 0.05% $NaH_2PO_4$ and 0.05% $CaCl_2$ were best for the enzyme activity. The enzyme production was reached to highest level after the cultivation for 8 days at $25^{\circ}C$. Native polyacrylamide gel electrophoresis (PAGE) followed by the laccase activity staining using 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as the substrate was performed to identify the laccase under culture conditions studied. Zymogram analysis of the culture supernatant showed a laccase band with molecular mass of 52 kDa. The optimum pH and temperature for the enzyme activity were $80^{\circ}C$ and pH 3.0.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.5.2-5.2
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• 2010

인체 경조직인 뼈와 치아는 콜라겐 단백질과 인산칼슘 무기질 성분으로 구성된 최적의 복합체라 볼 수 있다. 이러한 인산칼슘 무기질 성분은 결정학적, 화학적으로 hydroxyapatite (HA, Ca10(PO4)6(OH)2)와 거의 유사하여 높은 생체활성과 골전도성을 보이는 것으로 알려져 있다. 또한, hydroxyapatite의 고온 분해 산물로 볼 수 있는 tricalcuim phosphate(TCP, Ca3(PO4)2)는 체내에 이식시 체액에 용해되어 신생골을 유도하는 생체흡수성 세라믹스로 알려져있다. 이러한 HA와 TCP는 우수한 생체친화성에도 불구하고 기계적 특성이 낮아, non-load bearing 부위에 적용이 되어 다공질의 골수복재 용도로 활용되거나, load-bearing부위의 적용을 위한 금속 implant 등의 생체친화성 보완을 위한 표면 코팅재로 사용되고 있는 실정이다. 본 발표에서는 생체특성이 매우 우수한 인산칼슘 생체세라믹스의 load-bearing part 적용을 위하여 강도 및 파괴인성의 기계적 특성을 증진시킨 사례를 살펴보고, non-load bearing part에 실제 사용되는 인산칼슘 생체세라믹스의 다공질(porous) 골수복재(bone graft)의 역학 특성 증진을 위한 아이디어와 함께, 역학 특성이 매우 뛰어난 지르코니아 생체세라믹스의 강화-소결법에 대하여 소개하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3285-3294
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• 2012

A field test on mud flat remediation was carried out in order to observe the effects of the treatments such as microbial dose and an oxygen releasing compound like $CaO_2$. The size of each treatment site was $100m^2$ and the dosage was 3.6 kg per site. The 6 week monitoring showed that pH on two sites was below 7 and ORP increased from .178~-188 mV to .121~-142 mV. In Ignition loss and COD there were no significant changes. Meanwhile nitrogen and phosphorus concentrations changed: ammonia concentration decreased both on control and treatment sites. Nitrate nitrogen decreased more on combined treatment site than on single microbial treatment (11.3% vs. 7.3%) probably because the extra oxygen supplied by $CaO_2$ formed more oxic environment so that the facilitated nitrification might produce more nitrate but the nitrate would be much rapidly released into the water layer out of the sediment. That also explains the total nitrogen reduction(6.1%). Similarly, T-P and $PO_4-P$ reduced by 29% and 31.8%, respectively on combined treatment sites, resulting from the phosphorus release effect though the initial concentrations of the two factors were considerably high.

• Journal of the Korean Chemical Society
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• v.9 no.1
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• pp.16-22
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• 1965

The time-lag-effect of alkali salts on the gelation of sodium alginate-$CaSO_4{\cdot}$1/2 $H_2O$ is compared with Miyake's data, and then the formation rate of the elastics measured by the continuous method (an improved Schwedoff's method) and the change of rigidity with metallic oxides are studied as follows: (1) The gelation processes of sodium alginate and $CaSO_4{\cdot}$1/2 $H_2O$-aqueous sol are studied by measuring, continuously the increases of tensions ofsamples. (2) The time-lag-effect of $Na_3PO_4$ on the formation rate of the elastic gel is larger than that of $Na_2CO_3$, but the difference between the effects of the two alkali salts on the rate is found not so greater than predicted in Miyake's data. (3) Any regularities of the effect on the rate by metallic oxides are not observed. The increasing effects of the rates of $SiO_2$ and MgO are relatively large, and that of ZnO is relatively small. However, $Al_2O_3$, $Sb_2O_3$ and $TiO_2$show some decreasing effects. As a result it is noted that the regularities do not depend on the effect of oxide species and their amounts. (4) It is not found proportionality between the rigidity and the gelation rate. However, the increasing effect of the rigidity with the addition of metallic oxides can be observed. The rigidity increasing rate of MgO is the largest of them.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1998.10a
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• pp.82-87
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• 1998

단고추의 자루재배에 의한 양액재배시 $NO_3$$^{-}$ 와 $NH_4$$^{+}$의 비율을 8:2와 10:0으로 하였을 때, 배지 종류에 따른 생육, 수량 및 무기성분 흡수에 미치는 영향을 구명하기 위하여 실험한 결과는 다음과 같다. 1. 배지의 무기성분 중 P 및 Mg는 버미큘라이트+왕겨에서, K는 펄라이트+버미큘라이트에서 높았다. 배지내 Ca의 농도가 가장 높았으며, 8:2보다 10:0에서 배지내 무기성분의 농도가 높았다. 2. $NO_3$$^{-}$ : $NH_4$$^{+}$ 비율에 따른 양액의 pH 및 EC는 모든 배지에서 작물재배에 적합한 범위를 유지하였으며, pH는 10:0에서 더 안정적이었고, EC는 8:2에서 높게 유지되었다. 3. 초장과 경경은 배지에 따른 생육차가 없었으며, 옆면적은 버미큘라이트+왕겨에서, 생체중, 건물중 등은 피트모스+훈탄에서 무거웠다. 생육은 $NH_4$$^{+}$를 첨가한 8:2의 모든 배지에서 10:0에 비하여 증가하였다. 4. 8:2에서의 과수 및 수량은 버미큘라이트+왕겨에서 17.53개와 1,5889으로 많았으며, 10:0에서의 과수는 버미큘라이트+왕겨에서 16.44개로, 수량은 필라이트+피트모스에서 1,394g으로 많았다. 8:2의 모든 배지에서 10:0에 비하여 과수, 수량, 평균과종, 과경, 과장 및 상품과율 등이 증가하였다. 5. 무기성분은 8:2와 10:0의 경우 $K^{+}$는 잎과 줄기에서, $Ca^{2＋}$ 는 뿌리에서, $Mg^{2＋}$ 는 잎에서 많았으며, $PO_4$$^{-}$ 는 과실과 줄기에서 많았다. 배지간에 따른 차이는 나타나지 않았으며, $K^{+}$, $Ca^{2＋}$ 및 $Mg^{2＋}$ 는10:0에서, $PO_4$$^{-}$ 는 8:2에서 각각 많았다.

• KSBB Journal
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• v.5 no.4
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• pp.355-363
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• 1990

Methanol-utilizing bacterium isolated from sewage samples in Seoul showed optimal temperature and pH of $33^{\circ}C$ and 7.1 for growth, respectively. The maximum specific growth rate was $0.42hr^{-1}$. The minimum medium composition was reconstituted depending on the surplus and the deficit of each component in the basal medium at steady state. The optimal composition was given as(g/l); Methanol 40, $(NH_4)_2\;SO_42, \;KH_2PO_4\;1.5, \;K_2HPO_4\;0.2, \;H_3PO_4\;0.79, \;Na_2HPO_4{\cdot}12H_2O\;0.15, \;MgSO_4{\cdot}7H_2O\;1.5, \;FeSO_4{\cdot}7H_2O\;0.034, \;MnSO_4{\cdot}4H_2O\;0.005, \;CuSO_4{\cdot}5H_2O\;0.0027, \;CaCl_2{\cdot}2H_2O\;0.25, \;ZnSO_4{\cdot}7H_2O\;0.007, \;(NH_4)_6\;Mo_7O_{24}{\cdot}4H_2O\;0.00048, \;H_3BO_3\;0.00068, \;CoCl_2\; 0.00024$ Under the continuous culture with optimum medium the maximum cell productivity was 3.8g/1/hr at dilution rate $0.23hr^{-1}$. Maximum cell concentration and its protein content were 19.5g/l and 70% at dilution rate of $0.1hr^{-1}$, respectively.

• The Korean Journal of Ceramics
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• v.5 no.2
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• pp.162-164
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• 1999

Microsotructure designed porous ceramics of calcium hydroxyapatite $(Ca_{10}(PO_4)_6(OH)_2)$ were prepared by hydrothermal method. The particle size, shape, and the micro-pore size of the porous hydroxyapatite ceramics could becontrolled. The hydroxyapatite was non-stoichiometric apatite with calcium deficient compositions (Ca/P ratio < 1.67). The composition of non-stoichiometric hydroxyapatite ceramics could be controlled from 1.50 to 1.63 in Ca/P ratio. The hydroxyapatite ceramics preparedc at $105^{\circ}C$ under the saturated vapor pressure for 20h were composed of rod-shaped crystals with about 10$\mu\textrm{m}$ in length with the mean aspect ratio of 40. The porous ceramics of calcium deficient hydroxyapatite had about 45% porosity with the inter-connecting pore structure. Porous hydroxyapatite ceramics prepared hydrothermally had the compressive strength of about 10 to 30 MPa. In addition, porous ceramics of $\beta$-tricalcium phosphate ($\beta-Ca_3(PO_4)_2$) were prepared from the calcium deficient hydroxyapatite.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.401-401
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• 2022

우리나라 대규모 하수처리장에 상용화되어있는 응집공정의 운영상 난점을 극복하고자 대체공정으로 고안된 인 결정여과공정(HCF, Hydroxyapatite Crystallization-Filtration process)의 pilot plant를 구축하고 부산슬러지의 자원화를 위해 그 특성을 검토하였다. 기존의 hydroxyapatite(HAP) 결정화공정 내 탈탄산(decarbonation) 단계를 생략하는 HCF공정의 경우에 고농도의 Ca²⁺ 주입과 처리수내 탄산염으로 인해 HAP을 포함하는 석회계 슬러지가 발생하는데, 이는 산성화된 토양의 개량제(중화제)로 널리 사용될 수 있다. 본 연구를 위해 경기도 I하수처리장 2차침전지 후단에 구축된 처리용량 27.1 - 135.6 m³/day HCF pilot plant의 전처리 조건은 pH 10.0 - 11.0, Ca²⁺ 농도 80 mg/L이었다. 결정여과조는 선속도 1.0 - 5.0 m/hr, 상향류로 운전되며, 여재는 2.0 - 3.0 mm의 석회석 모래를 충전하였다. 역세척은 중앙에 Air lifting pipe를 설치하여 역세척수가 처리수와 분리배출되도록 설계하였고, 침전시켜 역세척 슬러지를 회수하였다. 처리수의 평균 T-P, PO₄-P 및 SS는 각각 0.05, 0.04, 1.1 mg/L으로 모든 항목에서 방류수 수질기준 이하로 안정적으로 유출되었다. 회수된 HCF 슬러지는 SEM-EDX, XRD, FT-IR을 활용하여 그 특성을 분석하였다. SEM-EDX로 분석된 슬러지의 원자분율은 CaCO₃ 또는 HAP으로 추측되었다. 또한, XRD spectrum 분석결과, 슬러지의 주요 구성성분은 calcite, HAP, phosphoric acid(H₃PO₄) 및 brusite로 나타났다. FT-IR 분석결과, 슬러지는 대부분 인산염 및 탄산염의 무기물로 구성되어 있으며, 유입수의 인 농도가 높을수록 슬러지 내 HAP의 함량이 calcite보다 높은 것으로 나타났다. 고농도의 Ca²⁺을 주입하여 탈탄산단계를 생략한 HCF의 부산슬러지는 HAP 이외에도 CaCO₃와 칼슘-인 화합물로 구성되어 있는 것으로 나타났다. 하수 인 고도처리를 위한 HCF공정의 하수처리시설 인 고도처리 적용이 검증되었으며, 부산슬러지를 산성화된 토양의 개량제(중화제) 또는 비료로서의 재활용 및 자원화 가능성이 시사되었다.

• Journal of the Korean Ceramic Society
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• v.50 no.4
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• pp.275-279
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• 2013

The purpose of this study was to prepare calcium phosphate cement [CPC] for use in artificial bone. Nano-crystalline calcium phosphate [CaP] was precipitated at $37^{\circ}C$ using highly active $Ca(OH)_2$ in DI water and an aqueous solution of $H_3PO_4$. From the XRD measurements, the nano-CaP powder was close to apatitic TCP phase and the powders fired at $800^{\circ}C$ showed a critical ${\beta}$-TCP phase. A mixture of one mole $CaCO_3$ and two moles di-calcium phosphate was calcined at $1100^{\circ}C$ to make a reference ${\beta}$-TCP material. The nano-CaP powders were added to the normal ${\beta}$-TCP matrix and fired at $900^{\circ}C$ to make a ${\beta}$-TCP block. The sintered block showed improved mechanical strength, which was caused by the solid state interaction between nano-CaP and normal ${\beta}$-TCP.

• Journal of the Korean Ceramic Society
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• v.45 no.10
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• pp.625-630
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• 2008

In the bone cement composed of dense granules of $\beta-Ca_3(PO_4){_2}(\beta-TCP)$ and $Ca(H_2PO_4){_2}H_2O$, the compressive strength, setting time and temperature rise were measured to observe the degradation of cement with respect to the stored days before setting. Decreases of compressive strength and temperature rise were observed, while setting time increased with respect to the stored days. The similar trends were repeated with the increase of temperature of storage. Such a change virtually meant the fading of the character of cement and it took place only when the two starting materials were mixed during storage. The degradation could be mitigated taking advantage of granular $\beta$-TCP instead of powdery one. The formation of $CaHPO_4$, which resulted from reaction with ambient humidity, was attributed to the degradation observed during storage. Dependence of the degradation behavior on mixing and temperature during storage was discussed in terms of the driving force for reaction of cement.