• 생명과학회지
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• 제15권1호
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• pp.136-140
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• 2005

다양한 라세믹 에폭사이드 기질에 대한 입체선택적 가수분해 반응을 촉매하는 epoxide hydrolase 활성을 측정할 수 있는 미생물 세포 기반의 자외선 활성 분석법을 최적화하였다. 2.5 mg/ml의 세포 농도에서도 비교적 쉽게 흡광도 변화량을 인식할 수 있는 흡광도 범위인 0.5 이상을 얻을 수 있고, 반응 동력학 분석에도 응용할 수 있었다. 기존의 GC, HPLC 분석 법 보다 분석 시간을 줄일 수 있으며, 효소를 별도로 분리$\cdot$정제하지 않고 미생물 세포 자체의 epoxide hydrolase활성 분석이 가능하므로 상업적 특성이 우수한 epoxide hydrolase을 가진 미생물을 효율적으로 선별하는데 응용될 수 있을 것으로 기대된다.

• 한국항해항만학회지
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• 제33권2호
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• pp.161-166
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• 2009

Lactobacillus sp., Acetobacter sp. and yeast were the most dominant organisms in the EM stock culture and subculture product. Lactic acid bacteria and yeast were able to grow in the fermentation process utilizing seawater. EM treatment of higher concentrations using EM stock culture and EM clay balls (1% or 4%) contributed to an early removal of malodor and an increase of DO in the polluted sediments, indicating an odor-removing activity of EM. The EM treatment of higher concentrations (1% or 4%) somewhat appeared to modify the microbial communities within the sediments, which was confirmed by existence of a few unique fragments from the stock culture based on PCR-DGGE. It still remains to be elucidated that EM cultures were directly involved in the malodor removal and potential sediment bioremediation.

• Journal of Dairy Science and Biotechnology
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• 제29권2호
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• pp.69-73
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• 2011

Food borne pathogens are a growing concern for human health and food safety throughout the world. Milk and dairy products are commonly associated with spoilage or contamination from a wide variety of physical, microbial, and chemical hazardous. Microbiological risk analysis consists of three components: risk assessment, risk management, and risk communication, and overall objective of this process is ultimately public health protection. The microbiological risk assessment is useful tool to evaluate food safety as it is based on a scientific approach. In addition risk assessment process includes quantitative estimation of the probability of occurrence of microbial hazards to evaluate more accurate human exposure. The aim of this study is to review the microbiological risk assessment on the prevalence of bacterial foodborne pathogens in milk and dairy products.

• Animal Bioscience
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• 제35권8호
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• pp.1279-1288
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• 2022

Objective: The aim of this study was to investigate antioxidant activities of cinnamon (Cinnamomum cassia) extracts (extracted with different solvents) at various concentrations and to determine product quality of raw chicken patties added with different levels of cinnamon powder (CP) and oyster mushroon powder (OMP) during storage. Methods: After cinnamon was made into oven dried CP and extracted with water and different levels (50%, 80%, and 100%) of ethanol, antioxidant activities of these extracts were determined. CP and OMP were combined at different levels and added to raw chicken patties. Physicochemical properties and microbial counts were measured during refrigerated storage. Results: Cinnamon ethanol (80%) extract showed the highest (p<0.05) by 2,2-diphenyl-1picrylhydrazyl-radical scavenging activity and reducing power. Cinnamon water extract (CWE) had the highest iron chelating ability (p<0.05), while CP 100% ethanol extract had the highest content of total phenolic compound. Then, CP and OMP were applied to chicken patties at different levels (0.1% to 0.2%). After the addition of CPs, pH, L* (lightness), 2-thiobarbituric acid reactive substance, and volatile basic nitrogen values were decreased, whereas a* (redness) and b* (yellowness) values were increased. Microbial counts of total bacteria and Enterobacteriaceace were decreased with the addition of CP 0.2% regardless of the OMP level. Conclusion: The addition of CP in combination with OMP can increase the shelf-life of chicken patties during storage.

• Journal of Microbiology and Biotechnology
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• 제32권5호
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• pp.672-679
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• 2022

Microbial lipases are used widely in the synthesis of various compounds due to their substrate specificity and position specificity. 4-Ethyl malate (4-EM) made from diethyl malate (DEM) is an important starting material used to make argon fluoride (ArF) photoresist. We tested several microbial lipases and found that Photobacterium lipolyticum M37 lipase position-specifically hydrolyzed DEM to produce 4-EM. We purified the reaction product through silica gel chromatography and confirmed that it was 4-EM through nuclear magnetic resonance analysis. To mass-produce 4-EM, DEM hydrolysis reaction was performed using an enzyme reactor system that could automatically control the temperature and pH. Effects of temperature and pH on the reaction process were investigated. As a result, 50℃ and pH 4.0 were confirmed as optimal reaction conditions, meaning that M37 was specifically an acid lipase. When the substrate concentration was increased to 6% corresponding to 0.32 M, the reaction yield reached almost 100%. When the substrate concentration was further increased to 12%, the reaction yield was 81%. This enzyme reactor system and position-specific M37 lipase can be used to mass-produce 4-EM, which is required to synthesize ArF photoresist.

• 한국수산과학회지
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• 제56권5호
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• pp.721-727
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• 2023

This study was conducted to evaluate the level of microbial contamination in smoked salmon products sold in hypermarkets in major metropolitan cities in Korea. Listeria monocytogenes is the primary cause of smoked and raw salmon product recalls. Here, we used L. monocytogenes as a bacterial hygiene indicator and investigated the microbial contamination level of frozen/refrigerated smoked salmon products collected from hyper markets. Contamination levels were analyzed by seasons, manufacturers, and consumption regions. For hygiene indicator bacteria, total bacteria count, coliforms, and Escherichia coli were examined according to the food code established by the Ministry of Food and Drug Safety, and polymerase chain reaction (PCR) was performed to detect Listeria sp. The highest contamination level was observed in spring in Busan among five consumption regions. Listeria was detected at a level of 2.1% among all samples collected. And especially L. monocytogenes was detected in two cases from the samples collected from Daegu and Daejeon. Sanitary standards and specifications should be established according to the contamination level of smoked salmon products investigated in this study, and continuous monitoring is necessary.

• 식품보건융합연구
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• 제10권2호
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• pp.13-17
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• 2024

Oxygen is necessary to sustain life, but reactive oxygen species (ROS) produced by oxygen metabolism can cause mutations and toxicity. ROS can damage cellular macromolecules, leading to oxidative stress, which can accelerate cell death and aging. ROS generated in food affect the taste, color, and aroma of food, and high levels of ROS in meat can cause spoilage. Superoxide dismutase (SOD) plays an important role in scavenging ROS in food and reducing their toxicity to organisms. SOD exerts its antioxidant effect by catalyzing the breakdown of O₂-• to H₂O₂. As a natural antioxidant, SOD has the ability to regenerate and maintain its activity over a long period of time without depletion, unlike chemical antioxidants that may have side effects or stability issues. This antioxidant effect of SOD has great potential in a variety of industries, and in the food industry it can be utilized to improve product quality and provide safe and healthy products to consumers. By disrupting the SOD2 and SOD3 genes in Candida albicans, we studied the effects of SOD2 and SOD3 genes on the antioxidant system, suggesting its potential as a natural antioxidant.

• 한국환경농학회지
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• 제36권1호
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• pp.36-42
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• 2017

BACKGROUND: Yuza seed by-product has been produced in a large amount from the agricultural farms in the southern area of Korea. It has been mostly abandoned after commercial process for the production of juice, jam and tea. The study on the reuse of the yuza seed by-product has received much attention as a bio-resource material for the production of active compound in agriculture. METHODS AND RESULTS: Insecticidal rhamnolipid-producing Pseudomonas sp. EP-3 was grown in mineral salt media with the yuza seed by-product at 2, 20, 50 and 100 g/L. The growth of EP-3 was accompanied by a increase in insecticidal activity against green peach aphid. The highest insecticidal activity was observed when EP-3 was grown in the medium containing 50 g/L of the seed sample, producing approximately 996 mg/L of rhamnolipid at 96 h. Palmitic acid, stearic acid, oleic acid and linoleic acid were determined as the major fatty acids of the seed sample. The EP-3 cultures grown on the fatty acid mixture extracted from the seed sample showed a aphid mortality similar to that of cultures grown on the seed sample. The EP-3 cultures grown on 50 g/L of the seed sample showed aphid mortality more than 90% under greenhouse conditions. CONCLUSION: This study suggested that the yuza seed by-product may be used as a renewable material for microbial production of rhamnolipid against green peach aphid.

• 한국산업융합학회 논문집
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• 제22권1호
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• pp.61-69
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• 2019

All the parts of lotus, including the seed, rhizome, leaf, stalk, petal, anther, pericarp, and fruit receptacle, have been used in traditional medicine system as a health beneficial supplement. However the most usually used from lotus plant is only the root. Therefore in this study, it will be discussed more the utilization of other parts of the lotus, namely the flower of lotus. The petals and stamens of lotus actually are also rich in bioactive components such as flavonoids and alkaloids, are used in the treatment of tissue inflammation, cancer, skin disease, and also for us as antidotes. One of the biotechnological process that can be used to improve the nutritional content, sensory, and also antioxidant activities is fermentation process. The final product desired from the fermentation process in this study is vinegar. The microbial strain powder used is Uinkin fermented powder with three variations of fermentation. The variations given in this study were initial sugar 32%, 24%, and 14% with the same fermentation temperature, $35^{\circ}C$ for 3 months. The results obtained showed that the pH value and sugar content of products during the fermentation process were decreasing during the fermentation process, with total polyphenol content of $283.7{\pm}97.6mg/100g\;QAE$, and total flavonoid content of $3.3{\pm}0.0mg/100g\;QAE$. For the DPPH radical scavenging ability of the fermentation product also increased in a concentration dependent manner, with ORAC activity of the product showed a high activity of $20.7{\pm}0.41{\mu}M$ TE. Therefore, fermentation process can be the one of method for improving the product. The efficiency of lotus flower vinegar fermentation can be reached with an initial sugar condition of 25% (sample B).

• 미생물학회지
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• 제54권4호
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• pp.369-378
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• 2018

본 연구는 순환여과양식시스템(RAS)에 있어서 복합프로바이오틱스의 적용이 넙치의 성장과 병저항성에 미치는 영향과 이 프로바이오틱스를 RAS에 생물증강처리 시 미생물군집 구조 및 수질에 미치는 영향을 평가하고자 실시하였다. RAS 내에서 80미의 넙치치어($25.7{\pm}7.6g$; $15.2{\pm}1.7cm$)에 프로바이오틱스 CES-AQ1를 첨가하여 사료를 제조하여(CES 사료; $1{\times}10^9\;CFU/kg$) 8주일 동안 급이하였다. 이 경우 넙치의 증체율, 비성장속도, 사료효율, 및 단백질 전환효율은 비유수식 양식시스템에 있어서 CON, PI 및 OTC 사료를 처리한 경우에 비해 1.5~2.5배 정도 높게 나타났다. 1주일간 병원균 저항성 시험에 있어서 비유수식에서 항생제함유 사료(OTC)를 급이한 경우와 RAS에서 CES 사료를 처리한 경우간에는 별 차이가 나타나지 않았다. 따라서 이 CES 프로바이오틱스를 RAS에서 넙치를 양식하는데 있어서 항생제 대용으로 활용할 수 있을 것으로 판단되었다. RAS의 생물여과막에서는 가장 높은 미생물다양성이 나타났으며 암모니아의 산화 및 탈질능을 가진 미생물이 관찰되었고, 병원미생물의 성장억제도 관찰되었다. 더구나 RAS 운전 19일 경과 시 암모니아가 0.5 mg/L이하의 농도로 감소하여 양호한 RAS 수질의 유지에 있어서 프로바이오틱스 처리가 효과가 있음이 밝혀졌다. 사료에 프로바이오틱스(CES-AQ1)를 첨가하여 넙치 장내 미생물이 안정화되고 또한 이 프로바이오틱스를 RAS 양식수에도 처리하여 RAS를 운전할 경우 건강한 넙치의 양식과 양호한 수질을 유지할 수 있어서 경제적이고 환경친화적인 넙치양식이 가능할 것으로 판단되었다.