• Journal of Applied Biological Chemistry
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• 제56권2호
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• pp.119-129
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• 2013

Thirteen different Streptomyces isolates were evaluated for their ability to produce keratinase using chicken feather as a sole carbon and nitrogen sources under solid state fermentation (SSF). Streptomyces sp. NRC 13S produced the highest keratinase activity [1,792 U/g fermented substrate (fs)]. The phenotypic characterization and analysis of 16S rDNA sequencing of the isolate were studied. Optimization of SSF medium for keratinase production by the local isolate, Streptomyces sp. NRC13S, was carried out using the one-variable-at-a-time and the statistical approaches. In the first optimization step, the effect of incubation period, initial moisture content, initial pH value of the fermentation medium, and supplementation of some agro-industrial by-products on keratinase production were evaluated. The strain produced about 2,310 U/gfs when it grew on chicken feather with moisture content of 75% (w/w), feather: fodder yeast ratio of 70:30 (w/w), and initial pH 7 using phosphate buffer after 8 days. Based on these results, the Box-Behnken design and response surface methodology were applied to find out the optimal conditions for the enzyme production. The corresponding maximal production of keratinase was about 2,569.38 U/gfs.

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.826-831
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• 2012

Acarbose, a pseudo-oligosaccharide, is widely used clinically in therapies for non-insulin-dependent diabetes. In the present study, S-adenosylmethionine (SAM) was added to selected media in order to investigate its effect on acarbose fermentation by Actinoplanes utahensis ZJB-08196. Acarbose titer was seen to increase markedly when concentrations of SAM were added over a period of time. The effects of glucose and maltose on the production of acarbose were investigated in both batch and fed-batch fermentation. Optimal acarbose production was observed at relatively low glucose levels and high maltose levels. Based on these results, a further fed-batch experiment was designed so as to enhance the production of acarbose. Fed-batch fermentation was carried out at an initial glucose level of 10 g/l and an initial maltose level of 60 g/l. Then, 12 h post inoculation, 100 ${\mu}mol/l$ SAM was added. In addition, 8 g/l of glucose was added every 24 h, and 20 g/l of maltose was added at 96 h. By way of this novel feeding strategy, the maximum titer of acarbose achieved was 6,113 mg/l at 192 h. To our knowledge, the production level of acarbose achieved in this study is the highest ever reported.

• 한국축산식품학회지
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• 제34권6호
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• pp.769-776
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• 2014

The goat placenta was fermented by Bacillus subtilis and the optimal fermentation parameters of strongest antioxidant capacity of peptides were obtained using response surface methodology (RSM). The effects of fermentation time, initial pH value and glucose content on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity of the goat peptides were well fitted to a quadric equation with high determination coefficients. According to the data analysis of design expert, the strongest DPPH radical scavenging capacity value was obtained with the following conditions: content of glucose was 2.23%, initial pH value was 7.00 and fermentation time was 32.15 h. The DPPH radical scavenging capacity commonly referring antioxidant activity showed a concentration dependency and increased with increasing peptide concentration. The effects of temperature and pH were assessed to determine the stability of antioxidant peptides prepared from goat placenta. Antioxidant peptides showed good stabilities when temperature was lower than $70^{\circ}C$. However, the antioxidant peptides lost antioxidant activities rapidly under alkaline and excessive acid condition. Ultrafiltration technique was performed to separate fermentation broth with different Mw (molecular weight). It was found that peptides in the range of < 3 KDa mainly accounted for the antioxidant activities.

• Korean Chemical Engineering Research
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• 제52권3호
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• pp.302-306
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• 2014

목질계 분해효소 활성 증대를 위해 밀짚을 이용한 고체발효에서 주요 발효인자의 최적화를 수행하였다. Trichoderma reesei와 Aspergillus niger를 이용한 혼합배양에서 고체발효에 주요한 영향을 미친다고 알려진 배양온도, pH, 수분함량과 고체기질 크기를 순차적 최적화를 진행하였다. 실험에 적용 된 인자 모두 목질계 분해효소 활성에 유의한 효과를 주었으며, 발효온도 $40^{\circ}C$, pH 7, 수분함량 75%와 고체기질 크기 0.25~0.5 mm가 목질계 분해효소 생산을 위한 최적 조건임을 알 수 있었다. 최적조건 하에서 밀짚을 이용한 고체발효를 수행하였을 때, 효소활성 기준 cellulase 10.3 IU, endoglucanase 100.3 IU, ${\beta}$-glucosidase 22.9 IU와 xylanase 2261.7 IU/g dry material을 배양 96시간에 확인할 수 있었다. 본 결과는 기존 효소활성 대비 각각 72.6, 48.7, 55.2와 51.9% 증가한 수치로 혼합배양과 순차적 최적화를 적용하여 효과적인 목질계 분해효소 활성 증대가 가능함을 확인하였다.

• Food Science and Biotechnology
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• 제14권5호
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• pp.576-580
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• 2005

Ten yeast strains affecting doenjang flavor were isolated from soybean fermented foods (traditional meju and doenjang), among which Zygosaccharomyces sp. Y-2-5, showing excellent growth, glucose consumption, pH, and flavor production, was selected. Higher alcohols produced by Zygosaccharomyces sp. Y-2-5 related to flavor were 2-propanol, 1-propanol, 2-methyl-1-propanol, 1-butanol, and 3.3-dimethyl-2-butanol. Optimal culture conditions for Zygosaccharomyces sp. Y-2-5 were 10% (w/v) NaCl, pH 4.0, 3.0% (w/v) glucose concentration, and inoculation time day 0 or 15 doenjang fermentation.

• Asian-Australasian Journal of Animal Sciences
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• 제23권6호
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• pp.825-832
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• 2010

The United Nations Convention on Biological Diversity defines biotechnology as "Any technological application that uses biological systems, dead organisms, or derivatives thereof, to make or modify products or processes for specific use" Biotechnology has made tremendous contributions to improve production efficiency of agriculture during the last century. This article reviews successful examples of application of bio-fermentation in improving swine nutrition efficiency mainly based on the authors'z own research experience. Production of feed grade supplemental amino acids by bio-fermentation allowed nutritionists to formulate accurate feed for optimal lean growth and reduced nitrogen excretion. Recent issues with high feed grain prices caused potential feed quality problems. Bio-fermentation allowed nutritionists to use exogenous supplemental enzymes such as phytase and NSPases in swine diets, thereby improving nutrient utilization and reducing nutrient excretion to the environment. Yeast metabolites are also produced by bio-fermentation and have been repeatedly shown to improve milk production of sows during early lactation even though actual mechanisms are still to be investigated. Bio-fermentation technology also allowed nutritionists to prepare vegetable protein sources with large protein molecules and anti-nutritional factors suitable for feeding newly weaned piglets, as selected microorganisms significantly reduce specific anti-nutritional factors and size of peptides. Preparations of vegetable protein sources suitable for newly weaned pigs will greatly contribute to swine nutrition by providing efficient alternatives to the use of animal protein sources that are often expensive and somewhat against societal preference. Considering the few examples listed above, biotechnology has closely influenced improvement of production efficiency in the swine industry. As we have limited resources to produce meat to satisfy ever-increasing global demands, extensive adaptation of biotechnology to enhance production efficiency should be continued. However, at the same time, wise and careful application of bio-technology should be considered to ensure production of safe food and to meet the expectations of our society.

• Journal of Microbiology and Biotechnology
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• 제22권1호
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• pp.100-106
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• 2012

In this study, the metabolite profiles of three Aspergillus strains during rice koji fermentation were compared. In the partial least squares discriminant analysis-based gas chromatography-mass spectrometry data sets, the metabolite patterns of A. oryzae (KCCM 60345) were clearly distinguished from A. kawachii (KCCM 60552) and only marginal differences were observed for A. oryzae (KCCM 60551) fermentation. In the 2 days fermentation samples, the overall metabolite levels of A. oryzae (KCCM 60345) were similar to the A. oryzae (KCCM 60551) levels and lower than the A. kawachii (KCCM 60552) levels. In addition, we identified discriminators that were mainly contributing tyrosinase inhibition (kojic acid) and antioxidant activities (pyranonigrin A) in A. oryzae (KCCM 60345) and A. kawachii (KCCM 60552) inoculated rice koji, respectively. In this study, we demonstrated that the optimal inoculant Aspergillus strains and fermentation time for functional rice koji could be determined through a metabolomics approach with bioactivity correlations.

• 한방비만학회지
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• 제15권2호
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• pp.123-130
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• 2015

Objectives: Samjung-hwan (SJH), a well-known traditional fermented herb formula recorded in Dongui Bogam, has been commonly used for prolonging life for four hundred years in Eastern Asia. However, fermented SJH has not been investigated in terms of microbial ecology until present time. Methods: SJH was fermented for five weeks and fermentation characteristics during SJH fermentation were performed including pH, acidity and microbial profiling. Also, we measured total polyphenol and total flavonoid contents and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. In order to select starter candidate, several lactic acid bacteria were isolated from fermented SJH. Results: pH of fermented SJH was decreased from 4.7 to 3.0 and acidity was increased from 0.45% to 1.72%. Also, fermented SJH increased antioxidant indicator such as total polyphenol and total flavonoid as well as DPPH free radical scavenging activity. Lactobacillus brevis was increased, Pseudanabaena sp. was decreased, and Lactococcus lactis subsp. lactis was stable during 5-week fermentation of SJH. L. brevis and L. plantarum were isolated from fermented SJH. Conclusions: Fermented SJH for four weeks had optimal effect on antioxidant and fermentation characteristics such as pH, acidity and microbial profile. Further studies are required to develop starter and analyze functional compounds in oder to produce standardized SJH.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.400-406
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• 2012

To improve the hydrogen yield from biological fermentation of organic wastewater, a co-culture system of dark- and photo-fermentation bacteria was investigated. In a pure-culture system of the dark-fermentation bacterium Clostridium butyricum, a pH of 6.25 was found to be optimal, resulting in a hydrogen production rate of 18.7 ml-$H_2/l/h$. On the other hand, the photosynthetic bacterium Rhodobacter sphaeroides could produce the most hydrogen at 1.81mol-$H_2/mol$-glucose at pH 7.0. The maximum specific growth rate of R. sphaeroides was determined to be 2.93 $h^{-1}$ when acetic acid was used as the carbon source, a result that was significantly higher than that obtained using either glucose or a mixture of volatile fatty acids (VFAs). Acetic acid best supported R. sphaeroides cell growth but not hydrogen production. In the co-culture system with glucose, hydrogen could be steadily produced without any lag phase. There were distinguishable inflection points in a plot of accumulated hydrogen over time, resulting from the dynamic production or consumption of VFAs by the interaction between the dark- and photo-fermentation bacteria. Lastly, the hydrogen production rate of a repeated fed-batch run was 15.9 ml-$H_2/l/h$, which was achievable in a sustainable manner.

• 한국식품과학회지
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• 제40권6호
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• pp.661-668
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• 2008

동치미를 김치냉장고에서 발효 숙성시켰을 때 풍미가 우수한 동치미를 장기간 먹을 수 있는 저장 조건을 확립하고자 온도별(5, 10, 15, $20^{\circ}C$)로 동치미의 발효숙성 특성을 살펴보고 이를 삼성사 김치 냉장고의 자동숙성모드($23^{\circ}C$에서 25시간 발효 후 $-1^{\circ}C$ 자동전환)에서 발효시킨 동치미와 비교하였다. 동치미의 관능이 가장 좋은 시기는 pH는 $3.9{\pm}0.1$, 그리고 산도는 $0.25{\pm}0.05%$로 나타났으며 $10^{\circ}C$ 및 $15^{\circ}C$에서 숙성시킨 동치미가 적숙기에 빨리 도달하면서도 관능평가 점수가 높아 초기 발효 온도대는 $10-15^{\circ}C$가 적합하다는 결과를 얻었다. 이에 반해 자동숙성모드에서 저장한 동치미는 30일 경까지 적숙기에 도달하지 못하였다. 김치냉장고 초기 발효 시간을 결정하기 위하여 동치미를 $10^{\circ}C$ 및 $15^{\circ}C$에서 저장하여 산도가 0.1, 0.2 또는 0.3%에 도달하였을 때 $-1^{\circ}C$에 7일간 저장하면서 동치미의 발효 진행 및 관능검사를 실시한 결과 $10^{\circ}C$에서 발효시킨 동치미가 $15^{\circ}C$ 발효군보다 탄산미가 높고 군덕맛의 강도는 낮아 종합평가 점수가 높았다. $-1^{\circ}C$에 저장한 동치미의 산도는 1주일 동안 $0.08{\pm}0.02%$ 증가하여 저장온도 $-1^{\circ}C$에서도 미생물의 발육을 완전히 억제되지 못하는 것으로 나타났다. 본 연구 결과 동치미를 김치냉장고에서 자동으로 발효 저장할 때 동치미의 특성을 최대화할 수 있는 조건으로 $10^{\circ}C$에서 산도가 0.2%에 도달하였을 때 까지 발효시킨 후 $-2.5{\pm}0.5^{\circ}C$로 전환할 것을 제안한다. 이러한 동치미는 계절에 상관없이 탄산미와 살얼음맛을 느낄 수 있고 군덕내의 발생은 장기간 억제할 수 있을 것으로 생각된다.