• 한국식생활문화학회지
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• 제32권6호
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• pp.566-575
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• 2017

This study was conducted to screen for superior strains for preparation of Cheonggukjang and identify the optimal fermentation time based on fermentation of lentils by various Bacillus subtilis strains. Bacillus count was significantly high at 48 hrs of fermentation (9.22-9.51 log CFU/g). In addition, the pH was significantly high in the range of 7.60-7.92 at 48 hrs fermentation, and the reducing sugar content was significantly high (0.89-1.45). The amino-type nitrogen content and ammonia-type nitrogen content were significantly increased with fermentation time. Additionally, the amylase activity was significantly high (3.05-4.22) at 48 hrs of fermentation, as was the protease activity (4.80-5.63). Bacillus subtilis S3 (5.63), S4 (5.60) were higher than S1 (4.80), S2 (4.92). The viscous substances and DPPH radical scavenging activity increased at 48 hrs, then decreased. Sensory evaluation revealed that lentil Cheonggukjang fermented by S3 showed the highest scores in color, smell, savory taste, sweet taste, viscous substance and overall acceptability. Therefore, 48 hrs of fermentation should be suitable for lentil Cheonggukjang fermented by Bacillus subtilis S3.

• 한국식생활문화학회지
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• 제37권6호
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• pp.519-528
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• 2022

The Cheonggukjang used in this study was made with four soybean cultivars grown and harvested at the National Agrobiodiversity Center of the National Academy of Agricultural Sciences: C1 (KLS87248), C2 (Nongrim 51), C3 (GNU-2007-14613), and C4 (Daewon). The soybeans were inoculated with Bacillus subtilis AFY-2 and fermented for 0, 12, 21, 36, 45, and 60 h in a culture room at 35℃. ABTS and DPPH radical scavenging activities were significantly increased upon fermentation for 12 hours in all samples and maintained or decreased after 21 hour The inhibition of NO production was significantly increased compared to the LPS-treated group, and the C2 sample showed inhibition of NO production at 12 hours of fermentation, and the C3 sample showed inhibition at 21 hours of fermentation. PCA analysis revealed that the ABTS and DPPH radical scavenging activity and NO production inhibitory activity reached peak levels around 12 h fermentation time for all samples. Our results indicate that the optimal fermentation time of the Cheonggukjang sample is 12 hours, confirming the high correlation of all experiments.

• 한국미생물·생명공학회지
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• 제27권3호
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• pp.223-229
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• 1999

The two optimal control algorithms, singular approximation and minimum principle, were compared in this paper. The switching time with singular approximation was determined with mathematical derivation and the optimal control profile of specific growth rate was also calculated with minimum principle. The optimal control profiles were calculated by making simple model correlating the specific cell growth rate and specific product formation rate. The optimal control profiles calculated by singular approximation approach were similar to stepwise form of those calculatd by minimum principles. With the minimum principle, the product concentration was 8% more than that of singular approximation. This performance difference was due to a linearization of a nonlinear function with singular approximation. This optimal approaches were applicable to any system with different optimal cell growth and product formation.

• KSBB Journal
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• 제25권2호
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• pp.187-192
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• 2010

S. cerevisiae ATCC 24858을 이용한 ethanol 생산에서, aeration 효과를 ethanol 수율, specific ethanol production rate, ethanol 생산성 측면에서 분석하여, 반복 유가식 공정전략을 설계하였다. Ethanol 수율과 ethanol 생산성은 공기를 0.33 vvm 넣었을 때, 공기를 넣지 않고 배양한 것에 비하여 더 큰 값을 보였고, 24시간 마다 배지를 교체한 배양이 36시간 마다 배지를 교체한 배양 보다 더 큰 값을 보였다. 총 ethanol 생산량 값이 가장 큰 경우는 0.33 vvm의 공기를 넣고, 배지를 24시간마다 완전히 갈아주었을 때이고, 이때 가장 많은 703.8 g의 ethanol이 생산되었다.

• KSBB Journal
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• 제28권6호
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• pp.366-371
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• 2013

Ethanol productions were performed by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes using seaweed, Enteromorpha intestinalis (sea lettuce). Pretreatment conditions were optimized by the performing thermal acid hydrolysis and enzymatic hydrolysis for the increase of ethanol yield. The pretreatment by thermal acid hydrolysis was carried out with different sulfuric acid concentrations in the range of 25 mM to 75 mM $H_2SO_4$, pretreatment time from 30 to 90 minutes and solid contents of seaweed powder in the range of 10~16% (w/v). Optimal pretreatment conditions were determined as 75 mM $H_2SO_4$ and 13% (w/v) slurry at $121^{\circ}C$ for 60 min. For the further saccharification, enzymatic hydrolysis was performed by the addition of commercial enzymes, Celluclast 1.5 L and Viscozyme L, after the neutralization. A maximum reducing sugar concentration of 40.4 g/L was obtained with 73% of theoretical yield from total carbohydrate. The ethanol concentration of 8.6 g/L of SHF process and 7.6 g/L of SSF process were obtained by the yeast, Saccharomyces cerevisiae KCTC 1126, with the inoculation cell density of 0.2 g dcw/L.

• Mycobiology
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• 제36권3호
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• pp.183-189
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• 2008

The production of aerial conidia of Lecanicillium lecanii 41185, a highly virulent fungus, by solid-state fermentation was studied for use as a biocontrol agent against aphids. Among several agro-industrial solid media, steamed polished rice was found to produce the highest amount of aerial conidia. The optimal conditions for aerial conidia production were determined to be a 28.5% moisture content in the rice, 25$^{\circ}C$ culture temperature, rice pH of 6.0, 75% ambient relative humidity, 4-dold seeding culture, 0.6% $KNO_3$, and 12 d of culture time. The conidia yield increased from $5.7\times10^9$ conidia/g polished rice to 18.2 $18.2\times10^9$ conidia/g polished rice following application of these optimized conditions.

• Korean Chemical Engineering Research
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• 제52권3호
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• pp.402-406
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• 2014

본 실험에서는 농부산물인 밀짚을 고체배지로 사용하여 Aspergillus niger NRRL 567에서 구연산 생산 시, 발효조건과 첨가제가 구연산 생산에 미치는 영향을 단일변수(one-factor-at-a-time) 최적화를 이용하여 주요 인자의 순차적 최적화를 수행하였다. 발효 72시간에서 온도, 수분함량, 입자크기, pH와 첨가제 농도를 최적화했을 때, 각각 $30^{\circ}C$, 70%, 0.5~1.0 mm, pH 5.5와 4% 메탄올 첨가조건에서 최대 구연산 생산인 206.0 g/kg 건조중량 (DM)을 확인할 수 있었다. 이는 최적화 이전 구연산 최고 생산인 74.5 g/kg DM 대비 177% 증가한 결과이다. 최적화 실험에서 도출된 조건을 밀짚, 옥수수대와 피트모스(peat moss)에 적용하여 고체발효를 수행하였을 때, 발효 120시간에서 각각 231.8, 213.8, 240.2 g/kg DM 구연산 생산을 확보하였다. 본 실험 결과는 밀짚과 옥수수대 등의 목질계 농부산물을 이용한 구연산 생산 시, 고체발효법이 기존의 액체발효법의 대체가 가능함을 시사하였다.

• 한국식품과학회지
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• 제24권5호
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• pp.456-462
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• 1992

본 연구는 간장의 속성발효를 위한 방법의 하나로 정어리육을 효소에 의하여 분해하고, 분해액을 유산균과 효모의 균체를 고정화하여 이를 column형 reactor를 이용하여 속성발효를 시도하였다. 이때 사용된 column 반응조는 유리제$(30{\times}50cm)$의 칼럼 3개에 Pediococcus halophilus R-22, Saccharomyces rouxii R-60과 Candida etchellsii H-50을 colloidal silic와 sodium alginate(1 : 5)의 혼합액으로 고정화하여 각각의 column에 충전시켰다. 이때의 최적조건은 pH5.2, 온도 $30^{\circ}C$, 식염농도 10%이었다. 발효 최적조건에서 96시간 경과시 P. halophilus R-22는 유산을 0.75%, S. rouxii R-60은 ethylalcohol을 2.5%, C. etchellsii H-50은 4-ethylguaiacol을 18 mg/l 생성하였다.

• KSBB Journal
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• 제23권6호
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• pp.504-508
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• 2008

국내산 라이밀을 이용한 바이오에탄올 생산을 위해 저온 전처리 공정을 도입하여 에탄올 생산성을 비교하였다. 라이밀의 경우 원료 특성상 증자 공정에서 점도 문제가 발생하는데, 이를 해결하기 위해 최적 전처리 조건을 탐색하였으며 이에 따른 에탄올 생산성을 비교하였다. 저온 조건과 점도 저하 효소를 사용함으로서 점도에 따른 발효 저해 현상 해결하였고 전처리 공정에 소요되는 전처리 공정비를 절감할 수 있었다. 또한 pH 조절(pH 4.5) 후 살균 처리 없이 바로 발효가 가능함을 확인할 수 있었다. 발효 초기 총당 함량은 $48{\pm}2.0\;g/L$이었으며, 발효 72시간 이후 에탄올 생성 농도는 $67.4{\pm}1.4\;g/L$, 톤당 에탄올 생산량은 410.9 L (dry base)로 효소 무첨가구보다 에탄올 농도와 톤당 수득량이 각각 15%, 20% 이상 증가하였다. 이와 같은 결과는 기존의 에탄올생산 공정과 비교하여 전처리 공정에 소요되는 시간을 30-50% 이상 줄일 수 있으며, 저온 공정에 따른 에너지 사용 절감 및 초기 시설 투자비를 줄일 수 있어 바이오에탄올 생산을 위한 대체 원료로 충분한 가능성을 보여 주었다.

• 동아시아식생활학회지
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• 제13권1호
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• pp.64-71
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• 2003

Physicochemical and sensory characteristics of Kakdugi substituted red pepper powder with red paprika powder during fermentation at 1$0^{\circ}C$ were compared with those of the control. The fermentation patterns of two Kimchies were similar. While the pH and the acidity of the control were 3.88 and 0.691%(as lactic acid), respectively, those of paprika, 3.85 and 0.690%(as lactic acid), respectively on the 10th day of fermentation, which is the optimal ripe time. Reducing sugar content and Lactobacilli number of paprika Kakdugi were higher than those of the control. The hardness and fracturability of Kakdugi radish were not significantly different from those of the control during fermentation. The Hunter color L, a and b values of both Kakdugies increased gradually until l0th day and then decreased. The a and ASTA value of paprika Kakdugi was higher than that of control, which is consistent with the results of sensory evaluation. Capsaicin and dihydrocapsaicin analyzed by HPLC were not detected in paprika Kakdugi. Sensory evaluation (unstructured scale, 10 points) showed the score of hot taste f3r paprika Kakdugi was lower than that of the control(p<0.05), whereas the score of over-all acceptabillity for paprika Kakdugi(8.0) was higher than those of control(6.1).