• KSBB Journal
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• 제23권3호
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• pp.187-192
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• 2008

Lysozyme-producing microorganisms were isolated to obtain bacteria which can efficiently solubilize microbial cells. Cells of normal and chloroform-treated Escherichia coli and Micrococcus Iysodeikticus were used as model substrates to isolate lysozyme-producing microorganisms and investigate the efficiency of cell lysis. The culture supernatant of the isolate New1 (98% similarity of 16S rDNA sequence with Thermomonas haemolytica) showed different lytic characteristics for different substrates. Thermal treatment (autoclave) of substrate cells showed a significant effect on cell solubilization by culture supernatant of the New1. For autoclaved substrate cells, E. coli, M. Iysodeikticus and chloroform-treated E. coli were solubilized by 58.7%, 49.4% and 79.1%, respectively, in the culture supernatant of New1. The lytic activity of New1 was mainly caused by lysozyme produced by the isolate. It was also showed that New1 exhibited high protease activity and a little cellulase activity.

• The Korean Journal of Ecology
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• 제22권1호
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• pp.45-50
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• 1999

김치 발효 초기에 bacteriocin 생성 유산균을 분리하고자 하였다. 분리 유산균은 형태, 배양 및 생리학적인 특징과 16S rDNA의 부분적인 염기서열로부터 Lactococcus lactis로 동정되었다. 분리균주가 생성한 bacteriocin은 Listeria monocytogenes, Staphylococcus aureus와 같은 그람 양성 병원성 세균과 몇몇 유산균에 대해 항균활성이 있었고, 그람음성균인 Yesinia에는 활성이 없었다. bacteriocin의 활성은 protease, protease ⅩⅣ, a-chymotrypsin과 pepsin에 대해서 활성이 소실되었으나, lipase, trypsin, lysozyme에 대해서는 활성이 유지되었다. bacteriocin의 활성은 pH 2∼11에서 안정적이며 l00℃에서 10분간 열처리시에도 변하지 않았다. 따라서 L. monocytogenes는 발효초기에 L. lactis에 의하여 억제될 수 있다.

• 한국미생물·생명공학회지
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• 제16권2호
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• pp.150-155
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• 1988

L-Lysine 생산균주인 Brevibacterium flavum ATCC 14067 과 Corynebacteriurn glutamicum ATCC13032에 섬유소 자화능이 우수한 Cellulomonas flavigena KFCC31221를 속간 융합시켜 섬유소로부터 L-lysine을 생산할 목적으로 이들 균주의 영양요구성 변이주 분리, 원형질체의 형성 및 재생의 조건을 조사하였다. NTG(500$\mu\textrm{g}$/$m\ell$)로 유기하여 penicillin-G(300$\mu\textrm{g}$/$m\ell$)로 농축한 변이주에서 B. flavum은 hse- str$^{r}$(100$\mu\textrm{g}$/$m\ell$), C. glutamicum는 Met$^{-}$T$hr^{-}$ Rif$^{r}$(5$\mu\textrm{g}$/$m\ell$), C. flavigena 는 T$hr^{-}$Val$^{-}$Kan$^{r}$(50$\mu\textrm{g}$/$m\ell$)의 gene marker를 가지는 영양요구성과 약제내성균주를 분리하였다. 공시균주의 원형질체 형성은 osmotic stabilizer로서는 0.5M sucrose, 배양기간은 대수증식기 중기의 균이 양호하였고, lysozyme 최적 처리 pH, 온도, 농도 및 반응시간은 각각 pH6.5, 33$^{\circ}C$, 500 $\mu\textrm{g}$/$m\ell$, 6시간으로 나타났으며, 이때의 원형질체형성율은 95-98%였다. 원형질체를 1.5% agar가 함유된 완전재생용 배지위에 0.7% agar가 함유된 완전재생용 배지로 중층했을 때 약 30~33%의 재생율을 보였다.

• Journal of Microbiology and Biotechnology
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• 제30권10호
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• pp.1552-1558
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• 2020

With an increase in the consumption of non-heated fresh food, foodborne shiga toxin-producing Escherichia coli (STEC) has emerged as one of the most problematic pathogens worldwide. Endolysin, a bacteriophage-derived lysis protein, is able to lyse the target bacteria without any special resistance, and thus has been garnering interest as a powerful antimicrobial agent. In this study, rV5-like phage endolysin targeting E. coli O157:H7, named as LysECP26, was identified and purified. This endolysin had a lysozyme-like catalytic domain, but differed markedly from the sequence of lambda phage endolysin. LysECP26 exhibited strong activity with a broad lytic spectrum against various gram-negative strains (29/29) and was relatively stable at a broad temperature range (4℃-55℃). The optimum temperature and pH ranges of LysECP26 were identified at 37℃-42℃ and pH 7-8, respectively. NaCl supplementation did not affect the lytic activity. Although LysECP26 was limited in that it could not pass the outer membrane, E. coli O157: H7 could be effectively controlled by adding ethylenediaminetetraacetic acid (EDTA) and citric acid (1.44 and 1.14 log CFU/ml) within 30 min. Therefore, LysECP26 may serve as an effective biocontrol agent for gram-negative pathogens, including E. coli O157:H7.

• 산업식품공학
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• 제14권3호
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• pp.263-270
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• 2010

Xylanase를 생산하는 호알칼리성 균주를 토양으로부터 분리하여 동정하였다. 토양으로부터 분리한 호알칼리성 균주 3000여종 중 xylanase 활성이 가장 높은 균주인 strain DK-2386 균주를 선별하였다. Gram 염색과 SEM을 통한 형태학적 특성을 관찰하였으며, Methods for General and Molecular Bacteriology와 Bergey's manual of systematic bacteriology, 그리고 Biochemical tests for identification of medical bacteria에 준하여 생화학적 특성을 확인한 결과 배양액의 색은 붉은 빛을 나타내었으며, Gram양성 간균, 내생포자형성, catalase 양성, oxidase 양성, 혐기성 양성, glucose로부터 gas 형성 양성, casein 가수분해 양성, starch 가수분해 양성, CMC 가수분해 양성, xylan 가수분해 양성, nitrate 환원능 양성이며 10% NaCl 농도에서도 생육하는 것을 확인하였다. 균체의 지방산 조성 분석 결과 $C_{15:0\;ISO}$ 27.35%와 $C_{15:0\;ANTEISO}$ 31.54%, $C_{16:0}$ 9.70%로 이루어져 Bacillus속으로 동정되었으며, 16S rDNA 염기서열 분석결과 B. agaradhaerens와 100%의 유사성을 갖는 것을 확인하였다. (사)한국종균협회로부터 분양받은 Bacillus agaradhaerens 40952, B. alcalophilus와 strain DK-2386 균주사이의 생화학적 특성을 비교한 결과 B. agaradhaerens와 속과 종이 같으나 미세하게 특성이 다른 균주로 판단되어 B. agarad haerens DK-2386이라 명명하였다.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.63-69
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• 2021

Carotenoids, which have biologically beneficial effects and occur naturally in microorganisms and plants, are pigments widely applied in the food, cosmetics and pharmaceutical industries. The compound 4,4'-diaponeurosporene is a C30 carotenoid produced by some Lactobacillus species, and Lactobacillus plantarum is the main species producing it. In this study, the antioxidant activity of 4,4'-diaponeurosporene extracted from L. plantarum subsp. plantarum KCCP11226 was examined. Maximum carotenoid content (0.74 ± 0.2 at A470) was obtained at a relatively low temperature (20℃). The DPPH radical scavenging ability of 4,4'-diaponeurosporene (1 mM) was approximately 1.7-fold higher than that of butylated hydroxytoluene (BHT), a well-known antioxidant food additive. In addition, the ABTS radical scavenging ability was shown to be 2.3- to 7.5-fold higher than that of BHT at the range of concentration from 0.25 mM to 1 mM. The FRAP analysis confirmed that 4,4'-diaponeurosporene (0.25 mM) was able to reduce Fe3+ by 8.0-fold higher than that of BHT. Meanwhile, 4,4'-diaponeurosporene has been confirmed to be highly resistant to various external stresses (acid/bile, high temperature, and lysozyme conditions). In conclusion, L. plantarum subsp. plantarum KCCP11226, which produces 4,4'-diaponeurosporene as a functional antioxidant, may be a potentially useful strain for the development of functional probiotic industries.