• 생명과학회지
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• 제25권12호
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• pp.1393-1398
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• 2015

다시마로부터 알긴산의 효율적인 추출, 침전, 회수조건은 1% Na₂CO₃, 80℃, 에탄올 침전 회수법이였고, 알긴산 분해효소(Flavobacterium sp. 유래 alginate lyase)를 이용한 저분자화 효소 반응 시 최적 초기 알긴산 농도는 3%였다. 알긴산 분해효소 농도에 따른 알긴산의 저분자화 정도에는 큰 차이가 없고, 경제적인 생산 비용을 고려하면 최적의 알긴산 분해효소 농도는 5 unit/ml였으며, 5 unit/ml의 알긴산 분해효소 농도로 37℃에서 3시간 반응하여 저분자화한 알긴산의 점도는 4.5 cp, 분자량은 307,008 Da였다. 3T3-L1 지방전구세포에 저분자화 알긴산을 125 μg/ml, 250 μg/ml 농도로 처리하였을 때 지방과립 형성과 triglyceride 중성지방 축적이 감소됨을 확인하였다. 따라서, alginate lyase로 저분자화된 알긴산은 지방세포 분화억제 효과가 있음을 확인하였다.

• 한국잠사곤충학회지
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• 제35권1호
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• pp.60-68
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• 1993

견층을 자연 건조하므로써 변성을 받지 않은 시료에 대하여 Bacillus licheniformis 단백질 분해 효소 정련과 비누 정련의 특성을 비교하기 위하여 널리 사용되고 있으며 용해할 때 비교적 피브로인에 대한 degradation이 적은 두가지 용해볍으로 용해한 견 피브로인 수용액에 대하여 분자 구조상의 차이가 있는지를 구명하고져 실험한 결과는 다음과 같다. 1. 견 피브로인 수용액의 편광 현미경으로 관찰한 결과 구정은 관찰되지 않았으나 나뭇잎 모양의 피브릴 구조가 나타났고 전자 현미경으로 관찰한 결과 구정의 크기는 30~120mm 정도였으며 정련 방법과 견 피브로인을 용해하는 방법에 따른 차이는 없었다. 2. 견 피브로인 수용액의 점도 측정 결과 비누 정련견 피브로인 수용액보다 효소 정련 견 피브로인 수용액의 intrinsic viscosity가 낮았다. 3. 견 피브로인 수용액에 대한 전기 영동 시험 결과 약 20kd에서 small submit와 50kd 이상에서 large subunit에 해당하는 폭 넓은 band가 나타났으며 정련 방법에 따른 차이는 없었다. 4. 견 피브로인 수용액을 냉동 건조한 분말에 대한 열 분해 온도는 비누 정련 견사와 효소 정련 견사간에 차이가 없었고 용해 방법에 따른 열 분해 온도는 cupric hydroxide-ethylene diamine법으로 용해하였을 때 조금 낮았다. 5. 견 피브로인 수용액을 송풍 건조한 시료에 대한 IR spectrum은 silk II형과 silk I형이 복합되어 나타났으며 정련 방법은 다른 차이가 없었다.

• Journal of Microbiology and Biotechnology
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• 제30권2호
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• pp.155-162
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• 2020

Acetyl xylan esterase (AXE; E.C. 3.1.1.72) is one of the accessory enzymes for xylan degradation, which can remove the terminal acetate residues from xylan polymers. In this study, two genes encoding putative AXEs (LaAXE and BhAXE) were cloned from Lactobacillus antri DSM 16041 and Bacillus halodurans C-125, and constitutively expressed in Escherichia coli. They possess considerable activities towards various substrates such as p-nitrophenyl acetate, 4-methylumbelliferyl acetate, glucose pentaacetate, and 7-amino cephalosporanic acid. LaAXE and BhAXE showed the highest activities at pH 7.0 and 8.0 at 50℃, respectively. These enzymes are AXE members of carbohydrate esterase (CE) family 7 with the cephalosporine-C deacetylase activity for the production of antibiotics precursors. The simultaneous treatment of LaAXE with Thermotoga neapolitana β-xylanase showed 1.44-fold higher synergistic degradation of beechwood xylan than the single treatment of xylanase, whereas BhAXE showed no significant synergism. It was suggested that LaAXE can deacetylate beechwood xylan and enhance the successive accessibility of xylanase towards the resulting substrates. The novel LaAXE originated from a lactic acid bacterium will be utilized for the enzymatic production of D-xylose and xylooligosaccharides.

• Macromolecular Research
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• 제16권5호
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• pp.473-480
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• 2008

In this study we investigated bacterial and cell adhesion to poly(propylene carbonate) (PPC) films, that had been synthesized by the copolymerization of carbon dioxide (a global warming chemical) with propylene oxide. We also assessed the biocompatibility and biodegradability of the films in vivo, and their oxidative degradation in vitro. The bacteria adhered to the smooth, hydrophobic PPC surface after 4 h incubation. Pseudomonas aeruginosa and Enterococcus faecalis had the highest levels of adhesion, Escherichia coli and Staphylococcus aureus had the lowest levels, and Staphylococcus epidermidis was intermediate. In contrast, there was no adhesion of human cells (cell line HEp-2) to the PPC films, due to the hydrophobicity and dimensional instability of the surface. On the other hand, the PPC films exhibited good biocompatibility in the mouse subcutaneous environment. Moreover, contrary to expectation the PPC films degraded in the mouse subcutaneous environment. This is the first experimental confirmation that PPC can undergo surface erosion biodegradation in vivo. The observed biodegradability of PPC may have resulted from enzymatic hydrolysis and oxidative degradation processes. In contrast, the PPC films showed resistance to oxidative degradation in vitro. Overall, PPC revealed high affinity to bioorganisms and also good bio-degradability.

• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1670-1679
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• 2020

The substantial use of fungal enzymes to degrade lignocellulosic plant biomass has widely been attributed to the extensive requirement of powerful enzyme-producing fungal strains. In this study, a two-step screening procedure for finding cellulolytic fungi, involving a miniaturized culture method with shake-flask fermentation, was proposed and demonstrated. We isolated 297 fungal strains from several cellulose-containing samples found in two different locations in Thailand. By using this screening strategy, we then selected 9 fungal strains based on their potential for cellulase production. Through sequence-based identification of these fungal isolates, 4 species in 4 genera were identified: Aspergillus terreus (3 strains: AG466, AG438 and AG499), Penicillium oxalicum (4 strains: AG452, AG496, AG498 and AG559), Talaromyces siamensis (1 strain: AG548) and Trichoderma afroharzianum (1 strain: AG500). After examining their lignocellulose degradation capacity, our data showed that P. oxalicum AG452 exhibited the highest glucose yield after saccharification of pretreated sugarcane trash, cassava pulp and coffee silverskin. In addition, Ta. siamensis AG548 produced the highest glucose yield after hydrolysis of pretreated sugarcane bagasse. Our study demonstrated that the proposed two-step screening strategy can be further applied for discovering potential cellulolytic fungi isolated from various environmental samples. Meanwhile, the fungal strains isolated in this study will prove useful in the bioconversion of agricultural lignocellulosic residues into valuable biotechnological products.

• Environmental Engineering Research
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• 제24권4호
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• pp.670-679
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• 2019

Lignin complexity molecule makes its biodegradation difficult during lignocellulosic wastes composting. So, the improvement of its biodegradation has usually been considered as an objective. This study aimed to determine the impact of Trametes trogii inoculation on organic matter and particularly on lignin and cellulose during green wastes co-composting with olive mill waste water sludge and coffee grounds. Three types of heaps (H1, H2 and H3) were investigated during 180 d. H3 and H2 were inoculated at the beginning of the process (t₀) and 120 d later (t₁₂₀), respectively while H1 was the control. Results showed the absence of pH stabilization in H3 during the first month. Also, in this period we observed a faster degradation of some easily available organic matter in H3 than in the other heaps. After 120 d, a better cellulose decomposition (25.28%) was noticed in H3 than in H1 and H2 (16%). Inoculation during the second fermentation phase induced supplementary lignin degradation in H2 with a percentage of 35% against 23 and 26% for H1 and H3, respectively. For all the runs, a Fourier Transform Infrared analysis showed aliphatic groups' decrease, OH groups' increase and lignin structural modification.

• The Plant Pathology Journal
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• 제15권4호
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• pp.223-227
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• 1999

Pre-penetration behavior of Boytryosphaeria dothidea on apple fruits was investigated with scanning electron microscopy. Once conidia were deposited on the fruit surface, they germainted and produced germ tubes from one or both ends of the conidia. Germ tubes grew over the fruit surface and entered the fruits through lenticels or surface cracks formed naturally. Germ tubes of the fungus also appeared to penetrated the fruits directly with or without forming appressoria. Globose appressoria were frequently formed at the tip of germ tubes on the fruit surface, where no lenticels or surface cracks were found. The conidia collapsed and became flattened to the fruit surface after appressorial formation. Cuticles of fruit surface underneath appressoria and tips of some germ tubes were evidently altered, indicating possibility of direct penetration of the fungus by enzymatic degradation of the cuticle layers. This the first report on the formation of appressoria by B. dothidea.

• 한국버섯학회지
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• 제14권2호
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• pp.51-58
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• 2016

Basidiomycetous fungi are one of the most potent biodegraders because many of its species grow on dead wood or litter, in environments rich in lignocellulose. For the degradation of lignocellulose, basidiomycetes utilize their lignocellulytic enzymes, which typically include laccase (EC 1.10.3.2), lignin peroxidase (EC 1.11.1.14), xylanase (EC 3.2.1.8), and cellulase (EC 3.2.1.4). In recent years, the practical applications of basidiomycetes have ranged from the textile to the pulp and paper industries, and from food applications to bioremediation processes and industrial enzymatic saccharification of biomass. Recently, spent mushroom substrates of edible mushrooms have been used as sources of bulk enzymes to decolorize synthetic dyes in textile wastewater. In this review, the occurrence, mode of action, general properties, and production of lignocellulytic enzymes from mushroom species will be discussed. We will also discuss the potential applications of these enzymes.

• Asian-Australasian Journal of Animal Sciences
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• 제14권3호
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• pp.321-325
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• 2001

Two experiments were conducted to examine the degradation rates of 4 tropical legume forages in rumen and intestine of Kedah-Kelantan (KK) cattle. Three KK cattle, averaging $173{\pm}17.15kg$ each fitted with a permanent ruminal and a T-shaped duodenal cannulae were used. The cattle were fed a maintenance diet (1% DM of their body weight) composing of 60% oil palm frond (OPF) pellet and 40% of a legume mixture of Arachis pintoi (AP) and Leucaena throughout the study. The overall DM and CP degradabilities in the rumen for Gliricidia sepium (GS) and AP were significantly higher than those for Leucaena leucocephala-Bahru (LB) and Leucaena leucocephala-Rendang (LR). This implies that LB and LR would have higher dietary protein flows into the intestine for the more efficient enzymatic digestion. However, the results of the present study suggested only limited proportions of the ruminal undegraded protein in the Leucaenas were digested in the intestine.

• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.360-367
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• 1997

The chemistry background of the Maillard reaction focused on pyrazines and factors affecting the reaction products were reviewed. The Maillard reaction, also called a non-enzymatic browning reaction, is quite complex and generates numerous reaction products. In processed foods, it is generally accepted as a key reaction to produce flavor components. Specially, pyrazines possess an important impact character on the roasted foods with other heterocyclic compounds. The Maillard reaction is initiated by condensation between reducing sugar and amino group, and N-glycosylamines are produced via Schiff base with dehydration of water. After the rearrangement of the N-glycosylamines, they follow transformation into deoxyhexosones which are reactive intermediates. Degradation and fragmentation are facilitated by rearranged compounds. By condensation, pyrazine, one of the final Maillard products, is generated as a relatively stable form to provide specific aromas. During the processes of the reaction, chemical or physical environmental parameters affect the formation of the products.