• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.251-259
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• 2013

An endoxylanase gene (PoxynA) that belongs to the glycoside hydrolase (GH) family 11 was cloned from a xylanolytic strain, Penicillium oxalicum B3-11(2). PoxynA was overexpressed in Trichoderma reesei QM9414 by using a constitutive strong promoter of the encoding pyruvate decarboxylase (pdc). The high extracellular xylanase activities in the fermentation liquid of the transformants were maintained 29~35-fold higher compared with the wild strain. The recombinant POXYNA was purified to homogeneity, and its characters were analyzed. Its optimal temperature and pH value were $50^{\circ}C$ and 5.0, respectively. The enzyme was stable at a pH range of 2.0 to 7.0. Using beechwood as the substrate, POXYNA had a high specific activity of $1,856{\pm}53.5$ IU/mg. In the presence of metal ions, such as $Cu^{2+}$, and $Mg^{2+}$, the activity of the enzyme increased. However, strong inhibition of the enzyme activity was observed in the presence of $Mn^{2+}$ and $Fe^{2+}$. The recombinant POXYNA hydrolyzed birchwood xylan, beechwood xylan, and oat spelt xylan to produce short-chain xylooligosaccharides, xylopentaose, xylotriose, and xylobiose as the main products. This is the first report on the expression properties of a recombinant endoxylanase gene from Penicillium oxalicum. The properties of this endoxylanase make it promising for applications in the food and feed industries.

• Environmental Engineering Research
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• 제18권4호
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• pp.229-234
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• 2013

This study aimed to develop a new dust collecting system equipped with an activated carbon (A.C.) coated electrode. Before fabrication, pre-treatment of A.C. was performed to remove metal ions within the A.C. to enlarge its specific surface area. Then, pre-treated A.C., black carbon, polyvinyl acetate (PVAc), and methanol were mixed to make a gel compound, which was coated onto aluminum plates to fabricate electrodes. The optimal mixing ratio of A.C., black carbon, PVAc, and methanol was found to be 10 g: 2 g: 3 g: 20 mL. After fabrication, the electrodes were used in the batch-type experiment for $NH_3$ and $H_2S$ removal. The reduction rates of the gases were high at the beginning and slowly reduced with time. Dust collection experiments were conducted in continuous flow, with various voltages applied. Compared to 5 kV, dust removal efficiency was 1.5 times higher when 10 kV was applied. Increasing the number of electrodes applied also increased the collecting efficiency. The correlation coefficient between actual collecting efficiency and trend line was higher than 99%. Consequently, the novel dust collection system equipped with A.C. coated electrode appears to be a promising substitute for existing dust-control devices.

• 한국식품영양과학회지
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• 제8권1호
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• pp.25-30
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• 1979

공장지역(工場地域) 폐수(廢水)로부터 cadmium에 대(對)한 내성균(耐性菌)을 분리(分離)하였으며 이것은 Staphylococcus aureus로 동정(同定)되었다. 동(同) 균주(菌株)는 cadmium 이외(以外)의 중금속(重金屬)($Cr^{3+},\;Hg^{2+},\;Zn^{2+},\;Pb^{2+},\;Cu^{2+}$ 등(等))에 의(依)하여서는 10ppm의 농도(濃度)에서 평균(平均) 약(約) 30%의 증식(增殖)이 저해(沮害)되었으나 cadmium에 의(依)해서는 50ppm까지는 저해(沮害)되지 아니 하였다. 동(同) 균주(菌株)의 증식(增殖)을 완전(完全)히 저해(沮害)하기 위(爲)하여 500ppm의 cadmium농도(濃度)가 필요(必要)하였으나 동(同) 균주(菌株)를 10ppm의 cadmium 또는 $Pb^{2+}$ 존재하(存在下)에서 15시간(時間) 배양(培養)한 세균(細菌)은 500ppm의 cadmium 존재하(存在下)에서도 증식(增殖)이 가능(可能)하였다. 이상(以上)의 결과(結果)로부터 분리(分離)한 균주(菌株)는 타중금속(他重金屬)에 의(依)해서는 생육(生育)이 쉽게 저해(沮害)되나 cadmium에 의(依)해서는 상당한 농도(濃度)까지 생육(生育)이 저해(沮害)되지 아니하는 균체(菌體), 즉(卽) cadmium에 특이적(特異的)인 내성균(耐性菌)으로 판단(判斷)되었다.

• 대한화학회지
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• 제31권1호
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• pp.31-36
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• 1987

용리 양이온의 바뀜에 따른 양이온착물에 대한 용리거동을 조사하였다. 높은 농도의 KCl, NaCl 및 $NH_4C$l수용액을 용리제로 사용하였을 때 친수성착물의 용리부피는 $NH_4^+ > Na^+ > K^+$의 순으로 증가하였지만 낮은 농도에서 친수성착물의 용리부피는 $Na^+ > NH_4^+ > K^+의 순으로 증가하였다. 반면에 전 농도 범위의 KCl, NaCl 및 NH_4Cl수용액을 용리제로 사용하였을 때 소수성착물의 용리부피는 NH_4^+ > Na^+ > K^+의 순서로 증가하였다. 그리고 용리음이온이 바뀜에 따른 양이온착물에 대한 용리거동을 조사하였다. 친수성착물은 할로겐화 이온중의 Cl-과 강하게 회합하였지만 소수성착물은 I-과 더 강하게 회합하였다. SO_4^2$-는 비교적 수화가 강하게 일어나므로 친수성 착물과 회합이 강하였고 소수성착물과는 회합이 약하였다.

• 대한화학회지
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• 제46권5호
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• pp.407-411
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• 2002

납이온과 선택적으로 상호작용하는 이온 운반물질(lead ionophore II)과 수소이온과 선택적으로 상호작용하면서 형광을 내는 변색성 이온 운반물질(ETH5294) 및 소수성의 음이온 자리를 포함하는 이온 선택성 광센서를 제조하여 형광분광법으로 수용액 중의 납이온을 정량하는 방법을 연구하였다. 시료용액의 pH,막두께 등이 형광세기에 미치는 영향을 조사하였다. $Na^+$, $K^+$, $Mn^{2+}$ 및 $Zn^{2+}$이온 등의 방해이온이 납이온의 정량에 미치는 영향을 조사하였다.본 연구에서 제작한 납이온 선택성 막을 이용하여 얻은 납이온 검정곡선의 직선범위는 5.0${\times}10^-7$M5.0${\times}10^-3$M이였고 이 범위에서의 상관계수는 -0099107이었다. 바탕용액의 상대표준편차는 3.0%였고 납이온의 검출한계는 5.0${\times}10^-9$M이었다.

• 한국동물위생학회지
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• 제29권4호
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• pp.459-467
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• 2006

This study was designed to investigate if there were groundwater contamination in 17 landfill where slaughtered animals were buried during the crisis of 2002 foot-and-mouth-disease (FMD) outbreaks in Gyeonggi province. From March to August 2005 groundwater was collected once a month from 17 sites, and examined with potential for hydrogen (pH), colour, turbidity, lead (Pb), arsenic (As), mercury (Hg), cadmium (Cd), copper (Cu), zinc (Zn) , iron (Fe), manganese (Mn) , aluminium (Al), nitrate-nitrogen $(NO_3-N)$, ammonia-nitrogen $(NH_3-N)$, microbial pathogen and Escherichia spp. In the examination of $NH_3-N$ which of the mean concentration was from not-detected (ND) to 0.05 mg/l. The range of $NH_3-N$ level was $0.3-24.1mg/{\ell}$. However, groundwater from four sites was to go beyond the drinking water quality standard (DWQS), i.e., the mean concentration of those were $15.5mg/{\ell}\;(site\;1),\;20.7mg/{\ell}\;(site\;9),\;24.1mg/{\ell}\;(site\;13)\;and\;10.6mg/{\ell}\;(site\;17)$. In the investigation of pH, colour and turbidity, all of the pH were below of DWQS (pH 5.8-6.6), but one site in color test and four sites in turbidity test were over the standard level. Among 9 metal ions examined, Mn was in excess of DWQS, and its concentration was $2.4mg/{\ell}$. Pb, Cd, Hg and As were not traced. The contents of Cu, Zn, Fe and Al were $ND-0.22mg/{\ell},\;0.01-0.05mg/{\ell},\;ND-0.05mg/{\ell}\;and\;0.03-0.16mg/{\ell}$, respectively. Escherichiae spp were not identified, but bacterial colonies were detected at 3 groundwater including 2 sites over the DWQS at the level of $491CFU/m{\ell}\;(site\;4)\;and\;217CFU/m{\ell}\;(site\;15)$.

• 한국식품영양과학회지
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• 제21권1호
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• pp.84-90
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• 1992

아그배로 부터 아세톤 침전, DEAE-cellulose 칼럼 크로마토그라피, Ultro-AcA 54겔여과의 과정을 거쳐 peroxidase를 분리 정제하고, 그의 특성을 조사하였다. 아그배peroxidase의 반응 최적 pH는 4.5, 반응최적 온도는 $80^{\circ}C$이었고, $30^{\circ}C$ 이하의 온도와 pH 5.0에서 안정하였으며, $80^{\circ}C$에서 15분간 보존했을 때 거의 불활성화되었다. OPDA에 높은 활성을 나타내었으나, phenol류 기질에 대해서는 약간의 활성을 나타내었으며, OPDA와 $H_{2}O_2$에 대한 Km치는 각각 1.65mM, 7.97mM이었다. 아그배 peroxidase에 대한 저해작용은 L-ascorbic acid와 sodium L-ascorbate가 가장 컸고, 금속이온 중 $Mn^{2+}$만이 5mM 농도에서 효소의 활성을 증가시켰다.

• 자원리싸이클링
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• 제16권6호
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• pp.52-60
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• 2007

탈질 특허분석과 전해기초연구를 통하여 수용액으로부터 질소의 환원제거에 대하여 조사하였다. 세계적으로 수용액으로부터 질소를 제거하는 방법으로 생물학적 기술과 산화환원 기술이 개발되고 있으며, 최근 들어 전해기술에 대한 특허출원도 증가하고 있다. 전해법에서 Fe를 음극으로 Pt를 양극으로 채택한 정전류 전해법에 의하여 1시간동안 총질소를 47% 이상 제거할 수 있었다. 질소함유 폐수를 처리하는 효율적인 방법은 폐수 특성에 맞는 기술의 조합이라고 말할 수 있다. 예를 들어 고농도 질소 함유 폐수를 소량 배출하는 경우 화학적 처리와 전해법의 조합으로 질산성 질소를 아질산성 질소로 일차 전환시켜 전해효율을 극대화시키면서 2차 오염원인 용해 금속이온을 전해과정에서 음극에 환원 회수하는 방법 등이 실용화에 유리하다고 말할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1477-1483
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• 2004

We present the tandem mass spectrometry applications carried out to elucidate the coordination structure of Zn(II) bound lysine ternary complexes, $(Zn+Lys+Lys-H)^+$, which is a good model system to represent a simple (metallo)enzyme-substrate complex (ES). In particular, experimental efforts were focused on revealing the involvement of a lysine side chain ${\varepsilon}$-amino group in the coordination of $Zn^{2+}$ divalent ions. MS/MS fragmentation pattern showed that all the oxygen species within a complex fell off in the form of $H_2O$ in contrast to those of other ternary complexes containing amino acids with simple side chains (4-coordinate geometries, Figure 1a), suggesting that the lysine complexes have different coordination structures from the others. The participation of a lysine basic side chain in the coordination of Zn(II) was experimentally evidenced in MS/MS for $N{\varepsilon}$-Acetyl-L-Lys Zn(II) complexes with acetyl protection groups as well as in MS/MS for the ternary complexes with one $NH_3$ loss, $(Zn+Lys+Lys-NH_3-H)^+$. Detailed structures were predicted using ab initio calculations on $(Zn+Lys+Lys-H)^+$ isomers with 4-, 5-, and 6-coordinate structures. A zwitterionic 4-coordinate complex (Figure 7d) and a 5-coordinate structure with distorted bipyramidal geometry (Figure 7b) are found to be most plausible in terms of energy stability and compatibility with the experimental observations, respectively.

• 농업과학연구
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• 제43권3호
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• pp.424-431
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• 2016

The nutrients in livestock manure produced during fermentation processes in public livestock recycling centers are used as fertilizers. However, the large amounts of swine manure produced in intensive livestock farms can be a nonpoint source of pollution. In this experiment, we investigated the chemical properties, inorganic components, and heavy metal contents in 101 samples of liquid swine manure collected from 28 public livestock recycling centers throughout the nation. Results showed that the average pH of the samples was alkaline (pH range 5.18 to 9.54), and their maximum EC was $53.2dS\;m^{-1}$. The amounts of total nitrogen and total phosphorus were in the range of 1000 - 2000 and $200-800mg\;L^{-1}$ while potassium, which constituted 47% of the total inorganic ions recovered from the liquid swine manure, amounted to $1500mg\;L^{-1}$. The most distinctive heavy metals recovered from the liquid swine manure were copper and zinc although the amounts of both heavy metals were much lesser than those of the standards as livestock liquid fertilizer set by the Rural Development Administration. On the other hand, the amount of nitrogen decreased rapidly with an increasing fermentation period from immature to mature, assumed to be lost as volatile compounds, such as ammonia, which are the major odor components during the fermentation process.