• 한국식품과학회지
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• 제12권2호
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• pp.88-96
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• 1980

아미노-카르보닐 반응에 대한 반응 조건을 검토하고 반응성에 미치는 아미노산(酸)의 영항에 대하여 검토한 결과 다음과 같은 결과를 얻었다. 1. 아미노-카르보닐 반응은 알칼리성이 강할수록 melanoidin 생성량은 크게 증대되었으며, 아미노산의 등전점 이상에서 반응 속도는 더욱 증가되는 것으로 나타났다. 2. 당(糖)과 아미노산(酸)의 몰 분비(分比)가 1:1일 때까지 melanoidin 생성량은 직선적으로 증가되었으며, 당과 아미노산(酸)은 1:1로 결합함을 알 수 있었다. 3. 아미노-카르보닐 반응은 시간과 반응 온도에 높은 의존성을 보였으며, 동(同) 몰의 glucose-glycine 계(系)에서의 활성화 에너지는 37.5Kcal/mole이었다. 4. 사용된 아미노산(酸) 중(中)에서 glycine, lysine 및 $\beta$-alanine이 당과의 반응성이 현저하게 높았으며, 산성(酸性)아미노산(酸)의 반응성은 아주 낮았다. 따라서 산성(酸性) 아미노산(酸)의 측쇄(測鎖)의 카르복실기(基)는 아미노기(基)의 반응성에 가장 저해(沮害) 결과(結果)를 나타내었다. 5. 사용된 당류(糖類)의 반응성은 다음의 순서로 나타났다. Xylose>arabibose>fructose>glucose>maltose>lactose.

• Journal of Microbiology and Biotechnology
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• 제8권1호
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• pp.14-20
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• 1998

Syntheses of the B. stearothermophilus xylanolytic enzymes such as xylanases, ${\beta}$-xylosidases, ${\alpha}$-arabinofurano-sidases, and esterases, were observed to be regulated by the carbon source present in the culture media. Xylan induced synthesis of ${\beta}$-xylosidase at the highest level while xylose gave about 30% of the ${\beta}$-xylosidase activity induced by xylan. The lowest syntheses of the xylanolytic enzymes above mentioned were detected in the basal medium containing glucose as a sole carbon source. When a mixture of xylan and glucose was used as a carbon source, we could observe glucose repression of xylanase (about 70-fold) and ${\beta}$-xylosidase (about 40-fold) syntheses. Whereas, the level of the glucose repression of the expression of the xylA gene encoding the major ${\beta}$-xylosidase of B. stearothermophilus was assessed to be about l0-fold when the relative amounts of the xylA transcript were determined. From the sequence of the xylA gene, we could find two CRE-like sequences (CRE-l: nucleotides ＋124 to ＋136 and CRE-2:＋247 to ＋259) within the reading frame of the xylA gene, either or both of which were suspected to be involved in catabolite repression of the xylA gene.

• Journal of Forest and Environmental Science
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• 제15권1호
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• pp.77-88
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• 1999

소나무류의 뿌리나 토양에서 분리된 균근균의 배양특성 비교와 인공접종에 의한 소나무 묘목에의 균근형성을 시도하였다. 소나무류 균근균은 다양한 생장특성을 지니고 있었는데, 배지별 생장에서 민자주방망이버섯(Ln73/92)은 PDA 에서, Paxillus sp.는 FDA 에서, 알버섯(FRI91017)은 Hagem배지에서, 나머지 균근균들은 MP배지에서 생장이 양호하였다. 용도나 pH를 달리한 배양조건에서 대부분의 균근균들은 $25^{\circ}C$에서 생장이 양호하였으나 모래밭버섯(FRI91004와 Pt 1)은 $30^{\circ}C$가 최적온도였고, pH도 균근균의 종류에 따라 약산성에서부터 약알칼리성에 이르기까지 최적 pH가 다양하였다. 생장시에 선호하는 탄소원의 종류도 균근균의 종류에 따라 다양하였으나 탄소원으로 xylose를 첨가한 배지에서는 모든 균근균의 생장이 불량하였다. 질소원은 $KNO_3$ 또는 asparagine을 선호하는 종류가 많았고 urea를 첨가한 배지에서는 거의 모든 균근균이 생장하지 못하였다. 균근균을 해송묘목에 인공접종하여 균근균을 형성시킨 결과, 모래밭버섯인 Pt1균주만 3개월만에 성공적으로 균근을 형성하여 외생균근의 전형적인 특징인 두꺼운 균사막으로 덮인 분지된 세근이 관찰되었으며 조직염색법에 의해 처리된 균근형성뿌리의 횡단절단면을 Nomarski interference microscope로 관찰하여 표피세포에 형성된 fungal mantle과 피층세포에 형성된 Hartig net을 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제24권10호
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• pp.1427-1437
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• 2014

Enzymatic hydrolysis of lignocellulosic biomass into fermentable sugars is a key step in the conversion of agricultural by-products to biofuels and value-added chemicals. Utilization of a robust microorganism for on-site production of biomass-degrading enzymes has gained increasing interest as an economical approach for supplying enzymes to biorefinery processes. In this study, production of multi-polysaccharide-degrading enzymes from Aspergillus aculeatus BCC199 by solid-state fermentation was improved through the statistical design approach. Among the operational parameters, yeast extract and soybean meal as well as the nonionic surfactant Tween 20 and initial pH were found as key parameters for maximizing production of cellulolytic and hemicellulolytic enzymes. Under the optimized condition, the production of FPase, endoglucanase, ${\beta}$-glucosidase, xylanase, and ${\beta}$-xylosidase was achieved at 23, 663, 88, 1,633, and 90 units/g of dry substrate, respectively. The multi-enzyme extract was highly efficient in the saccharification of alkaline-pretreated rice straw, corn cob, and corn stover. In comparison with commercial cellulase preparations, the BCC199 enzyme mixture was able to produce remarkable yields of glucose and xylose, as it contained higher relative activities of ${\beta}$-glucosidase and core hemicellulases (xylanase and ${\beta}$-xylosidase). These results suggested that the crude enzyme extract from A. aculeatus BCC199 possesses balanced cellulolytic and xylanolytic activities required for the efficient saccharification of lignocellulosic biomass feedstocks, and supplementation of external ${\beta}$-glucosidase or xylanase was dispensable. The work thus demonstrates the high potential of A. aculeatus BCC199 as a promising producer of lignocellulose-degrading enzymes for the biomass conversion industry.

• 한국식품영양학회지
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• 제34권1호
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• pp.36-46
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• 2021

After ethanol (BM-E and RW-E) and hot-water (BM-HW and RW-HW) extracts were fractionated from two herbal mixtures (BM and RW), their physiological activities were investigated. All extracts consisted of more than 50% of neutral sugar, with their total polyphenol levels higher than flavonoid levels. Radical scavenging activities of EtOH extracts remained significantly higher compared to that of hot-water extracts, and in particular, RW-E showed consistently higher antioxidant activity than BM-E. When anti-inflammatory activities of the extracts were evaluated by LPS-stimulated RAW 264.7 cells at 10~500 μg/mL non-cytotoxicity doses, BM-E showed significantly higher levels of TNF-α, IL-1β, IL-6, and nitric oxide inhibitory activity than those of hot-water extracts and RW-E. Murine peritoneal macrophage cells were shown to be enhanced in crude polysaccharides (BM-CP and RW-CP fractionated from BM-HW and RW-HW) compared to hot-water extracts and polysaccharide K (PSK, positive control). Especially, RW-CP exhibited higher activity than BM-CP, and component sugar analysis showed that BM-CP mainly contained galacturonic acid, glucose, arabinose, galactose, and xylose (34.5%, 33.9%, 16.1%, 7.1%, and 6.3%, respectively), whereas RW-CP showed different measurements (29.5%, 59.2%, 5.0%, 4.5%, and 0.2%). In conclusion, two herbal mixtures could contain varying sets of physiological activities dependent on different extraction and fractionation methods.