• 한국미생물·생명공학회지
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• 제33권1호
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• pp.41-50
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• 2005

Leu. mesenteroides KCCM 35471을 변이처리하고 젖산과 초산이 2:1로 함유된 유기산 조정 배지에서 screening을 하여 유기산 내성 변이균주 M-200을 얻었다. 내산성 개량균주 M-200과 야생균주 LM-W는 $10^{\circ}C\~30^{\circ}C$ 온도범위와 pH $3.5\~4.5$의 영역에서 생육 특성에 대해 실험을 행하였다. 내산성 변이균주 M-200의 경우에는 HCI로 조절한 배지에서는 $10^{\circ}C$, pH 3.5영역에서도 증식하였다. 유기산으로 조절한 배지에서는 $10^{\circ}C$, pH 3.8의 영역까지 증식하였다. 내산성 변이균주 M-200과 야생균주 LM-W를 김치에 starter로 첨가하여 $10^{\circ}C$에서 발효시킨 결과를 살펴보면, 내산성 변이균주 M-200은 김치 발효가 끝나는 시점까지 산도 0.55 이하를 유지하였다. 이는 김치의 적숙 기간을 산도가 $0.4\~0.75\%$일 때로 본다면 내산성 변이균주 M-200을 첨가한 군은 발효기간 내내 적숙기를 유지한다는 것을 알 수 있었다. 또한 이를 야생균주 LM-W를 첨가한 군과 비교해보면 가식기간이 약 3.5배 연장됨을 볼 수 있었다. 그러나 지나친 M-200의 생육으로 Lac. plantarum의 생육이 떨어지고 김치의 산도가 올라가지 못하고 신맛이 부족하여 김치의 관능이 떨어졌다. 유기산 분석에 있어서도 젖산의 생산이 대조군에 비해 발효 21일째부터는 약 절반 정도 밖에 생산하지 못하였다 따라서 starter 첨가량 조절과 다른 변이주 들과의 혼합첨가를 한다면 좋은 관능을 갖는 김치를 생산할 수 있을 것으로 생각되었다.

• 유기물자원화
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• 제14권2호
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• pp.112-120
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• 2006

음식물류폐기물의 무항생제 액상사료화를 통한 고급자원화를 이루기 위하여 항생제 대체용 항세균 활성 유산균주 13 종을 돼지 장관 및 분변에서 분리하였다. 분리 유산균은 모두 내염성(Nacl 4%), 내산성 (pH4.0) 및 내담즙성 (oxgall 0.8%)을 보였으며, $37^{\circ}C$에서 생장이 가장 높게 나타났다. 분리 유산균주중 Lactobacillus plantarum CJY-22, Pediococcus sp. CJY-41, Lactobacillus brevis CJY-42 및 Lactobacillus arizonensis CJY-3 균주가 가장 높은 항세균 활성 및 광역의 항세균 활성 스펙트럼을 나타냈으며, Lactobacillus plantarum CJY-22 균주의 경우 $25^{\circ}C$에서도 생장이 원활하여 음식물류폐기물에 적용시 가온없이 발효공정을 수행할 수 있는 유용 균주로 적용할 수 있을 것으로 사료된다.

• 한국산학기술학회논문지
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• 제10권10호
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• pp.2990-2996
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• 2009

본 연구에서는 한국인 아동의 우식치아로부터 S. mutans를 분리하고, acid stress하에서 분리한 S. mutans의 유전자의 발현의 변화를 분석하고자 하였다. 치아우식증의 주요한 요소로 작용하는 치태형성에 기여하는 glucan 및 fructan 합성에 관여하는 세포내 효소인 glucosyltransferase B (gtf B), glucosyltransferase C (gtf C), glucosyltransferase D (gtf D) 및 fructosyltransferase (ftf )의 발현량의 변화를 확인한 결과, lactic acid를 처리하지 않은 control의 경우보다 16배에서 3배까지 감소한 것을 확인할 수 있었다. 이는 산 스트레스하에서 균주의 성장속도 및 대사능력이 감소한 결과에 기인한 것으로 생각되어진다. S. mutans가 다른 구강내 미생물들과는 달리 내산성 가질 수 있는 요인으로 스트레스단백질의 발현은 매우 중요하며 따라서 앞으로의 연구에서는 스트레스 단백질을 동정하고 유전자 발현형태 및 관련대사를 밝혀내는 연구가 계속적으로 행해져야 할 것이다.

• Journal of Animal Science and Technology
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• 제50권4호
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• pp.509-518
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• 2008

본 연구는 육계 및 산란계 맹장에서 분리하여 유기산 생성 능력, 내산성, 내담즙성 및 성장특성을 토대로 선발된 유산균 6종(Lacto- bacillus reuteri BLA5, Lactobacillus crispatus avibro1, Lactobacillus reuteri avibro2, Lacto- bacillus amylovorus LLA7, Lactobacillus crispatus avihen1, Lactobacillus vaginalis avihen2)의 효소, 항균 활성 및 항생제 감수성을 조사하여 생균제로서의 이용 가치를 구명하고자 실시하였다. 육계 및 산란계 맹장 유래 유산균은 효소 활성에 있어서는 균주마다 차이가 있었으나, 일반적으로 amylase와 lipase 활성이 강한 것으로 나타났고 반면, cellulase 및 protease의 활성은 약한 것으로 나타났다. 유산균 배양액은 병원성 E. coli에 대하여 강한 항균 활성을 보였으며, 주요 억제 요인으로는 유기산 분비에 의한 pH 저하에 의한 것으로 나타났다. 병원성 Salmo- nella에 대해서는 유산균 배양액의 억제성이 약한 것으로 나타났다. 유산균은 치료용 항생제로 이용되는 ampicillin과 amoxicillin에 대해서는 높은 감수성을 보인 반면 사료용 항생제(virginiamycin 및 salinomycin)의 경우 정상적인 첨가 수준에서는 영향을 받지 않았다.

• 한국식품저장유통학회지
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• 제30권1호
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• pp.52-64
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• 2023

100 different yeast colonies were isolated from spontaneously fermented kiwis, persimmons, apples, pears, watermelons, grapes, grape fruits, peachs, and plums, and selected yeast strains were used to produce kiwi-persimmon mixed wine (KPMW). Among the isolates, five representative strains exhibited tolerance to sucrose, alcohol, pH, and potassium metabisulfite when compared with the control yeast strain (Saccharomyces cerevisiae KCCM 12615). All five yeast strains (Y4, Y10, Y28, Y78, and Y81) exhibited 99% 26S rDNA sequence similarity to S. cerevisiae. The pH, acidity, Brix, reducing sugar, alcohol, and organic acid contents were consistent in KPMW prepared from the S. cerevisiae KCCM 12615 and Y28 strains. KPMW made from the Y4, Y10, and Y28 strains exhibited lower quantities of free sugars than those of the KPMW made from the other yeast strains. The level of ethyl esters in KPMW prepared from the Y28 was higher than that in the other KPMWs. All strains, except for Y28, produced lower concentrations of sulfur and ketone compounds. Furthermore, the KPMW produced by the Y28 strains had total phenolic contents with 1.1 g/L, with DPPH and ABTS radical scavenging activities of 57.06% and 55.62%, respectively, and a FRAP assay value of 0.72. Our results suggest that Y28 is a promising yeast strain for producing high-quality wines.

• 한국초지조사료학회지
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• 제37권3호
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• pp.248-253
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• 2017

Humic acid (HA) is known to consist of various kinds of polymeric organics, their detailed structures can vary depend on sample sources such as organic manure, composts, peat, and lignite brown coal, and largely exists in grassland soils. HA possesses diverse positive effects that not only increase plant growth but also improve soil fertility. Recently, we have manufactured a co-polymeric product of catechol and vanillic acid (CAVA) synthesized artificially, and found that CAVA as a HA mimic increases seed germination and salt tolerance in Arabidopsis. In this study, we examined whether HA or CAVA affects to seedling growth in alfalfa. Foliar application of HA or CAVA increased alfalfa seedling growth including aerial and in root parts. HA or CAVA dramatically enhanced size of leaf and root, whereas HA significantly displayed higher bioactivity than CAVA. Taken together, CAVA acts like as a HA mimic in alfalfa that could apply as an alternation supplement to enhance plant growth and productivity.

• 한국초지조사료학회지
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• 제37권3호
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• pp.242-247
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• 2017

Humic acid (HA) is a complex organic matter found in the environments, especially in grassland soils with a high density. The bioactivity of HA to promote plant growth depends largely on its extraction sources. The quality-control of HA and the quality improvements via an artificial synthesis are thus challenging. We recently reported that a polymeric product from fungal laccase-mediated oxidation of catechol and vanillic acid (CAVA) displays a HA-like activity to enhance seed germination and salt stress tolerance in a model plant, Arabidopsis. Here, we examined whether HA or CAVA enhances the growth of Italian ryegrass seedling. Height and fresh weight of the plant with foliar application of HA or CAVA were bigger than those with only water. Interestingly, enhanced root developments were also observed in spite of the foliar treatments of HA or CAVA. Finally, we proved that HA or CAVA promotes the regrowth of Italian ryegrass after cutting. Collectively, CAVA acts as a HA mimic in Italian ryegrass cultivation, and both as a biostimulant enhanced the early growth and regrowth after cutting of Italian ryegrass, which could improve the productivity of forage crops.

• Asian-Australasian Journal of Animal Sciences
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• 제33권7호
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• pp.1156-1166
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• 2020

Objective: The aim of this study was to evaluate the effects of compound organic acid calcium (COAC) on growth performance, hepatic antioxidant status and intestinal barrier of male broilers under high ambient temperature (32.7℃). Methods: Nine hundred healthy one-d-old Cobb-500 male broiler chicks were randomly assigned into three groups with six replicates of 50 birds each. A basal diet supplemented with 0% (control), 0.4% and 0.8% COAC, respectively were fed to birds for 6 weeks. All treatments were under high ambient indoor temperature of 32.7℃, and had a constant calcium and available phosphorus ratio. Results: The results showed that, compared with control, the average daily gain of broilers in 0.4% and 0.8% was significantly increased and the ratio of feed to gain in in 0.4% and 0.8% was significantly decreased at 1 to 21, 22 to 42 and 1 to 42 days of age (p<0.05). Compared with control, 0.8% COAC slightly decreased (p = 0.093) the content of malondialdehyde in liver at 42 days of age while 0.4% COAC significantly decreased (p<0.05) the activity of alkaline phosphatase. Furthermore, 0.4% COAC significantly enhanced the intestinal barrier function via increasing jejunal and ileal ocln transcription, promoting jejunal mucin 2 transcription at 42 days of age (p<0.05), and decreasing jejunal toll-like receptor 2 (TLR-2) and ileal TLR-15, inducible nitric oxide synthase compared with control group (p<0.05). Whereas, no significant differences on the transcription of interleukin-1β in jejunum and ileum were observed among three treatments (p>0.05). Overall, heat stress caused by high natural environment temperature may induce the damage to hepatic antioxidation and intestinal barrier. Conclusion: Dietary inclusion of COAC can improve the tolerance of broilers to thermal environment through the modification of antioxidative parameters in liver and the mRNA expression of genes in intestinal barrier, resulting in an optimal inclusion level of 0.4%.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.144-144
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• 2022

The amount of required forage is increasing by 20% every year in South Korea, but the cultivation area for forage production is limited. The yield ability of triticale forage is the highest among the winter forage crops including rye and the crop has cold tolerance within the average low temperature of -10℃ in January. Therefore, this study analyzed effects of sowing and harvesting times on feed value and quality for efficiently using and supplying triticale as livestock feed. Seed of the triticales, 'Joseong' was sown in 2021 fall (October) and 2022 spring (March). The triticales were harvested according to growth stages: seedling stage, booting stage, heading stage, 10 days after heading, and 20 days after heading. Moisture contents of each harvested triticales were adjusted to about 60%, and then the triticales were fermented for 40 days at room temperature under anaerobic conditions as silage. We have analyzed pH and organic acid to determine the feed value and quality of each silage. The contents of lactic acid in silage ofthe triticale harvested at the seedling stage of both fall and spring-sown (1.61%, 1.63%) were the highest among all of the silages; the booting stage (0.75%, 1.33%), the heading stage (0.50%, 0.69%), 10 days after the heading stage (0.31%, 0.42%), and 20 days after heading stage (0.22%, 0.40%). Such as the contents of lactic acid in the silages, and the pH value of the silages The pH value in both the fall- and spring-sown became lower as the triticale was grown up: seedling stage (7.05, 6.85), booting stage (6.21, 6.75), heading stage (6.18, 6.28), 10 days after heading stage (6.22, 6.17), and 20 days after heading stage (6.15, 5.81). Taken together, the results showed that the feed value and quality of triticale silage were more affected by harvesting time than sowing time.

• Journal of Microbiology and Biotechnology
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• 제30권4호
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• pp.615-621
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• 2020

Laccases are multicopper oxidases with important industrial value. In the study, a novel laccase gene (mco) in a Staphylococcus haemolyticus isolate is identified and heterologously expressed in Escherichia coli. Mco shares less than 40% of amino acid sequence identities with the other characterized laccases, exhibiting the maximal activity at pH 4.0 and 60℃ with 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) as a substrate. Additionally, the Mco is tolerant to a wide range of pH, heavy metal ions and many organic solvents, and it has a high decolorization capability toward textile dyes in the absence of redox mediators. The characteristics of the Mco make this laccase potentially useful for industrial applications such as textile finishing. Based on BLASTN results, mco is found to be widely distributed in both the bacterial genome and bacterial plasmids. Its potential role in oxidative defense ability of staphylococci may contribute to the bacterial colonization and survival.