• 동아시아식생활학회지
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• 제8권1호
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• pp.9-19
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• 1998

The purpose of this study was to investigate the effect of calcium intake on lipid contents and enzyme activities in rats of different ages. Lipid levels in serum and liver and GOT, CPK and LDH activities in serum were compared in rats of different ages(4 weeks and 10 months) that were fed various levels of calcium(50, 100, 200% of requirement)for 3 weeks. Body weight gain and feed efficiency ratio were significantly higher in young rats than in adults. Serum calcium level was increased by elevation of calcium intake levels were decreased. Liver phospholipid and triglyceride levels in the high-cal-terol and triglyceride levels were decreased. Liver phospholipid and triglyceride levels in the high calcium group were significantly lower than those in other groups. Serum GOT and LDH activities of adults were significantly higher in low-calcium group than those in adequate/high-calcium groups. However, serum CPK activity of adults was significantly higher in high-calcium group than that in low/adequate-calcium groups. The results of this study suggest that adequate calcium intake may have protective effects ont he alteration of lipid and enzyme activity in rats.

• Journal of Microbiology and Biotechnology
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• 제33권2호
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• pp.268-276
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• 2023

Alkyl butyrate with fruity flavor is known as an important additive in the food industry. We synthesized various alkyl butyrates from various fatty alcohol and butyric acid using immobilized Rhodococcus cutinase (Rcut). Esterification reaction was performed in a non-aqueous system including heptane, isooctane, hexane, and cyclohexane. As a result of performing the alkyl butyrate synthesis reaction using alcohols of various chain lengths, it was found that the preference for the alcohol substrate had the following order: C6 > C4 > C8 > C10 > C2. Through molecular docking analysis, it was found that the greater the hydrophobicity of alcohol, the higher the accessibility to the active site of the enzyme. However, since the number of torsions increased as the chain length increased, it became difficult for the hydroxyl oxygen of the alcohol to access the ^γO of serine at the enzyme active site. These molecular docking results were consistent with substrate preference results of the Rcut enzyme. The Rcut maintained the synthesis efficiency at least for 5 days in isooctane solvent. We synthesized as much as 452 mM butyl butyrate by adding 100 mM substrate daily for 5 days and performing the reaction. These results show that Rcut is an efficient enzyme for producing alkyl butyrate used in the food industry.

• 한국식품저장유통학회지
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• 제24권1호
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• pp.60-67
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• 2017

본 연구에서는 저온추출 뿐만 아니라 효소처리를 이용하여 생과형 블루베리 과일음료생산을 위한 최적의 방법을 확립하고자 하였다. 생리학적 기능성물질 추출 시 열에 의한 영양손실을 막기 위해 저온을 사용하였다. 또한 다양한 효소처리를 이용하여 혼탁 방지 및 추출수율 향상을 위한 최적의 추출조건을 확립하고자 하였다. 블루베리를 cellulase, pectinase 및 cellulase:pectinase(1:1) 혼합 효소와 효소 처리량, 추출온도, 추출시간, 추출 교반속도 등을 고려한 다양한 조건으로 추출하였을 때, 가장 우수한 추출 조건을 조사하였다. cellulase로 처리할 경우, 추출률이 85.72-86.55%, pectinase 처리구는 87.06-87.93%, cellulase:pectinase(1:1) 혼합 처리할 경우, 86.84-88.14%의 추출률을 나타냈다. 추출 온도는 $45^{\circ}C$에서 $87.91{\pm}0.05%$, 3시간 추출 하였을 경우 $87.88{\pm}0.10%$, 교반속도는 90 rpm에서 가장 높은 추출결과를 보였다. 블루베리 추출액의 당도 및 pH는 추출 조건에 관계없이 모든 처리구에서 통계학적으로 유사한 결과를 보였으나, 총 폴리페놀 함량은 pectinase 처리구에서 18.62 mg/g으로 가장 높은 값을 나타냈다. 유리당 함량은 모든 시료에서 과당과 포도당 두 가지 당류만 검출되었으며 cellulase 효소 0.10%를 처리한 블루베리 추출액의 유리당 함량이 포도당 0.51%, 과당 0.49%로 가장 높았으나 다른 처리구와 유의적인 차이는 없었다. 블루베리를 이용하여 생과일형 음료 제조를 위한 최적 조건은 cellulase: pectinase(1:1) 혼합효소 0.1%를 첨가하여 $45^{\circ}C$ 온도에서 90 rpm의 교반속도로 조사되었다.

• Korean Chemical Engineering Research
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• 제50권2호
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• pp.257-263
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• 2012

바이오디젤은 화석연료인 경유의 대체에너지로써 비독성이고 재생 가능한 에너지이다. 바이오디젤생산방법은 크게 산 염기 초임계 효소방법으로 분류되는데 본 연구에서 친환경적으로 바이오디젤을 생산할 수 있는 초임계공정과 효소고정화공정에 대해 연구하였다. 연간 10,000톤의 바이오디젤을 생산하는 공정을 대상으로 PRO II 공정모사기를 통해 전환률과 에너지소비량을 알아보기 위한 공정모사를 실시하였다. 그 결과 초임계공정에서의 전환률은 91.17%(0.9% 글리세롤 포함), 효소고정화공정에서는 93.58%(1.0% 글리세롤 포함)로 나타났다. 이 결과는 효소고정화공정이 높은 전환률을 보였지만 바이오디젤의 순도는 초임계공정에서 높게 나타났음을 보여준다. 한편, 에너지소비량 측면에서 초임계공정과 효소고정화공정이 각각 8.9, 3.9MW를 나타났다. 즉, 초임계 공정이 효소고정화공정에 비하여 2.3배 많은 에너지를 소모한다는 것을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제20권12호
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• pp.1681-1688
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• 2010

A screening for cellobiohydrolase (CBH) activity was performed and Fomitopsis pinicola KMJ812 was selected for further characterization as it produced a high level of CBH activity. An extracellular CBH was purified to homogeneity by sequential chromatography of F. pinicola culture supernatants. The molecular mass of the F. pinicola CBH was determined to be 64 kDa by SDS-PAGE and by size-exclusion chromatography, indicating that the enzyme is a monomer. The F. pinicola CBH showed a $t_{1/2}$ value of 42 h at $70^{\circ}C$ and catalytic efficiency of $15.8mM^{-1}s^{-1}(k_{cat}/K_m)$ for p-nitrophenyl-${\beta}$-D-cellobioside, one of the highest levels seen for CBH-producing microorganisms. Its internal amino acid sequences showed a significant homology with hydrolases from glycoside hydrolase family 7. Although CBHs have been purified and characterized from other sources, the F. pinicola CBH is distinguished from other CBHs by its high catalytic efficiency and thermostability.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.104-114
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• 2021

Petroleum-contaminated soil is considered among the most important potential anthropogenic atmospheric methane sources. Additionally, various rhizoremediation factors can affect methane emissions by altering soil ecosystem carbon cycles. Nonetheless, greenhouse gas emissions from soil have not been given due importance as a potentially relevant parameter in rhizoremediation techniques. Therefore, in this study we sought to investigate the effects of different plant and soil amendments on both remediation efficiencies and methane emission characteristics in diesel-contaminated soil. An indoor pot experiment consisting of three plant treatments (control, maize, tall fescue) and two soil amendments (chemical nutrient, compost) was performed for 95 days. Total petroleum hydrocarbon (TPH) removal efficiency, dehydrogenase activity, and alkB (i.e., an alkane compound-degrading enzyme) gene abundance were the highest in the tall fescue and maize soil system amended with compost. Compost addition enhanced both the overall remediation efficiencies, as well as pmoA (i.e., a methane-oxidizing enzyme) gene abundance in soils. Moreover, the potential methane emission of diesel-contaminated soil was relatively low when maize was introduced to the soil system. After microbial community analysis, various TPH-degrading microorganisms (Nocardioides, Marinobacter, Immitisolibacter, Acinetobacter, Kocuria, Mycobacterium, Pseudomonas, Alcanivorax) and methane-oxidizing microorganisms (Methylocapsa, Methylosarcina) were observed in the rhizosphere soil. The effects of major rhizoremediation factors on soil remediation efficiency and greenhouse gas emissions discussed herein are expected to contribute to the development of sustainable biological remediation technologies in response to global climate change.

• Fisheries and Aquatic Sciences
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• 제18권3호
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• pp.257-264
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• 2015

A 10-week feeding trial was carried out to investigate the feasibility of using spent coffee ground (CG) as a potential feed ingredient for olive flounder. Growth, feed utilization, body composition and antioxidant enzyme activity were examined. A control diet was formulated and three other diets were prepared to contain 5, 10 or 15% CG (designated as Con, CG5, CG10 and CG15, respectively) by replacing for wheat flour. Two hundred forty fish ($104{\pm}0.7g/fish$) were allotted to 12 circular tanks of 400 L capacity at a density of 20 fish per tank and fed the experimental diets twice daily. At the end of the feeding trial, fish fed the CG5 diet exhibited significantly (P < 0.05) higher growth performance than those fed the control diet. Also, fish fed the CG10 diet had a comparable growth to that of the control group, but further increase of dietary CG inclusion level to 15% resulted in significant decrease of growth performance. Fish fed the CG15 diet showed significantly lower feed efficiency and protein efficiency ratio than other treatments. Significantly lower muscle protein content was observed in fish fed CG15 diet compared to the control. Significant reduction in plasma cholesterol concentration was found in fish fed CG15 diet compared to control. No significant changes were found in alkyle and superoxide radicals scavenging activities of plasma, muscle and liver among dietary treatments. Also, liver total protein, total antioxidant capacity, catalase and glutathione peroxidase activities were not significantly influenced by dietary inclusion of CG. According to these results, we concluded that CG can be included up to 10% in the diet for olive flounder without any adverse effects on growth, feed utilization and antioxidant enzyme activity.

• 한국식품위생안전성학회지
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• 제13권3호
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• pp.268-273
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• 1998

Lard 와 Alcohol을 섭취시킨 흰쥐 혈청중의 효소 활성에 인삼추출물이 미치는 영향을 검토하기 위해서 흰쥐에 Lard 와 Alcohol 및 인삼추출물을 첨가한 식이를 10주간 급여하여 성장시킨 후 체중, 각종 장기 중량, 혈청중 AST, ALT, ALP, LDH의 활성을 측정하였을 때 다음과 같은 결과를 얻었다. Lard 와 Alcohol 첨가 식이군에서는 체중과 식이섭취량은 감소하였으나, 인삼추출물의 투여에 의한 식이효율은 증가하였다. lard의 첨가 식이로 성장시킨 실험군에서는 간장, 신장, 비장의 무게는 증가하였으나 다른 식이 군에서의 중량변화는 없었다. 혈청중 AST, ALT, LDH, ALP 활성은 lard , alcohol을 첨가한 식이군(II, III군)에 비해 유의한 감소를 나타내었다. 이상의 실험 결과로 보아 Lard 와 Alcohol의 만성적인 섭취는 실험동물의 간기능에 손상을 유발하여 혈청 중 AST, ALT, ALP, LDH활성이 증가하였으나 인삼추출물을 첨가한 실험군에서는 위와 같은 효소의 활성이 유의적으로 감소하였다. 따라서 인삼추출물은 고지방식이로 인한 고지혈증을 개선함으로써 간조직의 손상을 예방하여 줄것으로 생각되어 진다.

• Molecules and Cells
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• 제19권1호
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• pp.97-103
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• 2005

The role of residue C323 in catalysis by human glutamate dehydrogenase isozymes (hGDH1 and hGDH2) was examined by substituting Arg, Gly, Leu, Met, or Tyr at C323 by cassette mutagenesis using synthetic human GDH isozyme genes. As a result, the $K_m$ of the enzyme for NADH and ${\alpha}-ketoglutarate$ increased up to 1.6-fold and 1.1-fold, respectively. It seems likely that C323 is not responsible for substrate-binding or coenzyme-binding. The efficiency ($k_{cat}/K_m$) of the mutant enzymes was only 11-14% of that of the wild-type isozymes, mainly due to a decrease in $k_{cat}$ values. There was a linear relationship between incorporation of [$^{14}C$]p-chloromercuribenzoic acid and loss of enzyme activity that extrapolated to a stoichiometry of one mol of [$^{14}C$] incorporated per mol of monomer for wild type hGDHs. No incorporation of [$^{14}C$]p-chloromercuribenzoic acid was observed with the C323 mutants. ADP and GTP had no effect on the binding of p-chloromercuribenzoic acid, suggesting that C323 is not directly involved in allosteric regulation. There were no differences between the two hGDH isozymes in sensitivities to mutagenesis at C323. Our results suggest that C323 plays an important role in catalysis by human GDH isozymes.

• 한국산림과학회지
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• 제102권4호
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• pp.601-607
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• 2013

오존에 따른 피해 현상을 관찰해 보고 식물 수종에 따라 어떤 차이가 있는지 알아보기 위해서 소나무(Pinus densiflora)와 실내식물 가운데 많이 활용되는 스파티필름(Spathiphyllum patinii), 스킨답서스(Epipremnum aureum)의 항산화 효소인 GR(Glutathione Reductase), APX(Ascorbate peroxidase)의 활성, 광합성속도와 잎의 해부학적 피해 현상을 관찰하였다. 오존농도는 30 ppb로 유지했고, 50일 동안 하루 8시간(09:00~17:00) 오존을 처리한 후 다음과 같은 결과를 얻었다. 오존 농도가 30 ppb정도의 낮은 농도에서 소나무는 광합성속도, 수분이용효율, 항산화 효소의 활성, 잎의 해부학적인 특성에서 대조구와 크게 다르지 않은 것을 알 수 있었다. 반면에 실내식물인 스파티필름과 스킨답서스의 광합성속도, 항산화 효소의 활성(특히, GR의 활성), 잎의 해부학적 특성이 대조구와 오존 처리구간의 상당한 차이를 보여, 오존에 대한 민감성이 소나무에 비해 큰 것으로 나타났다.