• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2004년도 정기총회 및 제33차 춘계 학술대회
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• pp.89-119
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• 2004

This study was conducted to isolate lactobacilli having probiotic characteristics to be used as health adjuncts with fermented milk products. Acid tolerant strains were selected in Lactobacilli MRS broth adjusted to pH 4.0 from 80 healthy persons (infants, children and adults). And bile tolerant strains were examined in Lactobacilli MRS broth in which 1.0% bile salt was added. By estimation above characteristics, the strains No. 27, which was isolated from adult feces, was selected and identified as Lactobacillus salivarius subsp. salivarius based on carbohydrate fermentation and 16S rDNA sequencing. It was used as a probiotic strain in fermented milk products. The pH of fermented milk decreased from pH 6.7 to 5.0 and titratable acidity increased from 0.3% to 1.0% by L. salivarius subsp. salivarius (isolation strain 20, 35, and 37), when incubated for 36 h at $37^{\circ}C$. The number of viable cell counts of fermented milk was maximized at this incubation condition. The SDS-PAGE evidenced no significant change of casein but distinct changes of whey protein were observed by isolated L. salivarius subsp. salivarius for titratable acidity being incubated by $0.9{\sim}1.0%$ at $37^{\circ}C$. All of the strains produced 83.43 to 131.96 mM of lactic acid and 5.39 to 26.85 mM of isobutyric acid in fermented products. The in vitro culture experiment was performed to evaluate ability to reduce cholesterol levels and antimicrobial activity in the growth medium. The selected L. salivarius subsp. salivarius reduced $23{\sim}38%$ of cholesterol content in lactobacilli MRS broth during bacterial growth for 24 hours at $37^{\circ}C$. All of the isolated L. salivarius subsp. salivarius had an excellent antibacterial activity with $15{\sim}25$ mm of inhibition zone to E. coli KCTC1039, S. enteritidis KCCM3313, S. typhimurium M-15, and S. typhimurium KCCM40253 when its pH had not been adjusted. Also, all of the isolated L. salivarius subsp. salivarius had partial inhibition zone to E. coli KCTC1039, E. coli KCTC0115 and S. enteritidis KCCM3313 when it had been adjusted to pH 5.7. The selected strains were determined to have resistances of twelve antibiotic. Strains 27 and 35 among the L. salivarius subsp. salivarius showed the highest resistance to the antibiotics. Purified ${\alpha}$-galactosidase was obtained by DEAE-Sephadex A-50 ion exchange chromatography, Mono-Q ion exchange chromatography and HPLC column chromatography from L. salivarius subsp. salivarius 27. The specific activity of the purified enzyme was 8,994 units/mg protein, representing an 17.09 folds purification of the original cell crude extract. The molecular weight of enzyme was identified about 53,000 dalton by 12% SDS-PAGE. Optimal temperature and pH for activity of this enzyme were $40^{\circ}C$ and 7.0 respectively. The enzyme was found to be stable between 25 and $50^{\circ}C$. ${\alpha}$-galactosidase activity was lost rapidly below pH 5.0 and above pH 9.0. This enzyme was liberated galactose from melibiose, raffinose, and stachyose, and also the hydrolysis rate of substrate was compound by HPLC. These results indicated that some of the L. salivarius subsp. salivarius (strain 27 and 35) are considered as effective probiotic strains with a potential for industrial applications, but the further study is needed to establish their use as probiotics in vivo.

• 한국초지조사료학회지
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• 제19권4호
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• pp.347-354
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• 1999

본 시험은 1998년 축산기술연구소 초지사료과 시험포장에서 수확시 숙기 및 젖산균 제제가 호밀 라운드 베일 사일리지의 품징에 미치는 영향을 구명하기 위하여 수행되었다. 시험설계는 분할구 배치법으로 주구로는 수잉기, 출수기 및 개화기에 수확하는 수확시 숙기를 두고 세구로는 무처리(control), Inoculant A 및 Inoculant B를 두고 3 반복으로 수행하였으며 라운드베일 사일리지 제조시 호밀은 수잉기에는 1일 그리고 출수기 및 개화기에는 0.5일간 예건 하였다. 저장 2개월 후 호밀 라운드베일 사일리지의 섬유소 함량(ADF 및 NDF)은 수확시 숙기가 지연됨에 따라 증가하였고(p<0.01), 첨가제 처리에 따른 차이는 없었다. 한편 IVDMD에 있어서도 수확이 지연됨에 따라 감소되었다. pH의 변화는 개화기에서 평균 4.35로 가장 낮았고 출수기에서 평균 4.91로 가장 높았다. 또한 젖산균 처리구는 대조구에 비해 유의적으로 낮게 나타났다. 무처리구의 건물 함량이 젖산균 처리구보다 높게 나타났다. 암모니아태 질소의 함량은 전체적으로 10% 미만으로 고품질 사일리지의 적정 수준에 도달하였으며, 젖산균 제제 이용은 암모니아태 질소 함량을 줄였다. 젖산 함량은 첨가제 처리로 증가한 반면 초산 및 낙산 함량은 감소하였다. 젖산 생성균의 수는 젖산균 처리구에서 대조구에 비해 2~3배 높게 나타났으며 개화기의 Inoculant B구에서 가장 높았다. 이상의 결과를 종합할 때 고품질의 호밀 라운드베일 사일리지 제조시에는 출수기 이후에 수확하여 젖산균 제제를 처리하는 것이 바람직한 것으로 나타났다.