• 생명과학회지
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• 제14권4호
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• pp.683-688
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• 2004

API test를 통해서 김치에서 분리한 유산균이 Lactococcus lactis subsp. lactis의 한 종임 을 확인하고 Lactococcus lactis subsp. lactis YH-10이라 명명하고, 생산된 박테리오신을 lacticin YH-10으로 명명하였다. Lactococcus lactis subsp. lactis YH-10을 $25^{\circ}C$, 3$0^{\circ}C$와 37$^{\circ}C$에서 배양한 결과 $25^{\circ}C$에서 박테리오신을 생성하였다. Lacticin YH-10은 여러 가지 단백질 분해효소에 의해 항균활성을 소실하였으므로, 단백질로된 박테리오신임을 확인하였다. 또한 $\alpha$-amylase, $\beta$-amylase, glucoamylase의 처리에도 활성을 일부 소실하였으므로 박테리오신의 분류 중 classIV에 속함을 알 수 있었다 Ammonium sulfate정제한 후 SDS-PAGE를 통해 박테리오신의 분자량이 대략 14kDa임이 확인되었다. Lacticin YH-10은 단백질계 물질로서 인체 내에서 분해가 가능하기 때문에 일반 화학 보존제 보다 인체에 안정함을 알 수 있다. Lacticin YH-10은 낮은 pH와 높은 온도에서 항균활성을 가지고 있기 때문에 식품보존제로서 이용할 수 있다.

• 한국미생물·생명공학회지
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• 제26권5호
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• pp.442-449
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• 1998

CGTase를 이용한 당전이 xylitol의 합성과 당전이 xylitol의 비피더스균 생육증식 효과에 대한 연구를 수행하였다. 수종의 세균류가 분비하는 CGTase의 xylitol에 대한 당전이능을 비교하였으며, Thermoanaerobacter sp. 유래의 CGTase가 가장 우수한 당전이능을 보였다. 각종 당공여체를 검토한 결과 압출전분이 가장 우수한 결과를 보였으며, 당전이 효소반응의 최적 조건을 검토하였다. 생성된 당전이 xylitol을 활성탄-셀라이트 칼럼 크로마토그래피를 이용하여 분리하여 두 개의 fraction인 F-I, F-II를 얻었다. 이들의 당쇄결합 양상을 FAB mass spectrometer와 $^{13}$C-NMR spectrometer, 그리고 glucoamylase을 이용한 효소소화법을 이용하여 분석한 결과 xylitol에 glucose와 maltose 분자가 $\alpha$-1,4 결합되어 있는 것으로 유추되었다. 얻어진 당전이 xylitol은 xylitol과는 달리 Bifidobacterium breve에 대한 생육촉진효과를 보였다.

• Journal of Microbiology and Biotechnology
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• 제3권4호
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• pp.232-237
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• 1993

A strain of yeast which can convert starch directly to ethanol was developed by the intergeneric protoplast fusion between Schwanniomyces alluvius possessing $\alpha$ amylase as well as glucoamylase with debranching activity and FSC-14-75 which previously had been formed from a heterologous transformation and subsequent intergeneric protoplast fusion. Fusants were selected on minimal medium after protoplasts of auxotrophic mutant of S. alluvius fused with heat-treated protoplasts of FSC-14-75 in the presence of 30%(w/v) PEG and 20 mM $CaCl_2$. The fusion frequency was in the range of $10^{-6}$ order. All fusants tested were intermediate types of parental strains for carbon compound assimilation, and their cell volumes were approximately 1.1 times larger than FSC-14-75 and 1.8 times larger than S. alluvius. The fusants were unable to sporulate like FSC-14-75, while S. alluvius could sporulate. In flask scale the most promising fusant, FSCSa-R10-6, produced 7.83%(v/v) and 10.17%(v/v) ethanol from 15% and 20% of liquefied potato starch, respectively, indicating that the fermetation efficiency of each case increased 1.2 times and 1.6 times than that of FSC-14-75. The elution pattern on DEAE-cellulose chromatography showed that FSCSa-R10-6 has four distinct amylase peaks of which two peaks originated from S. alluvius and the other two from FSC-14-75. These results suggest that the enhanced fermentation efficiency of the fusant might be due to almost-complemented parental amylases.

• 한국미생물·생명공학회지
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• 제15권6호
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• pp.408-413
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• 1987

토양으로부터 생 쌀보리 분해 효소 생산능이 있는 170주의 곰팡이와 4주의 방선균을 분리하여 이중 생 쌀보리 분해 효소 생산능이 가장 높은 No. 281 균주를 선정하여 동정한 결과 Rhizopus sp.로 밝혀졌으며, 밀기울을 기본 배지로 한 효소 생산 조건을 검토한 결과 효소 생산 최적 온도는 3$0^{\circ}C$, pH는 4.5-5.0 이고 배양 시간 5일 후에 최고의 역가를 보였다. 생쌀보리를 이용한 무증자 알코올 발효 실험에서는 분리한 Rhizopus sp. No. 281의 효소를 이용했을 때가 시판 효소보다도 에탄올 생성이 2% 증가된 결과를 나타내었다.

• Journal of Microbiology and Biotechnology
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• 제4권4호
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• pp.316-321
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• 1994

We investigated the possibility of industrial application and economit process of high temperature fermentation by thermotolerant alcohol producing yeasts as previously reported. From the 20% glucose media, the RA-74-2 produced 11.8% (v/v) ethanol at $32^{\circ}C$ (0.5% inoculum) and 10.6% (v/v) ethanol at $40^{\circ}C$ (3% inoculum), respectively. Also, 11.3% (v/v) ethanol was produced for 96 hours in the temperature-gradient fermentation. These results suggest that the RA-74-2 could isuccessfully be applied to save the cooling water and energy in industrial scale without re-investment or modification of established fermentation systems. When potato starch was used as the substrate for the RA-74-2, high temperature fermentation above $40^{\circ}C$ was more appropriate for industrial utilization because organic nitrogen was not necessary to economical fermentation. As the naked barley media just prior to industrial inoculation, taken from the Poongkuk alcohol industry Co., were used, 9.6% (v/v) ethanol was produced at $40^{\circ}C$ for 48 hours in jar-fermentor scale (actually, 9.5-9.8% (v/v) ethanol was produced at 30~$32^{\circ}C$ for 100 hours in industrial scale). The ethanol productivity was increased by the high glucoamylase activity as well as the high metabolic ratio at $40^{\circ}C$ Therefore, if the thermotolerant yeast RA-74-2 would be used in industrial scale, we could obtain a high productivity and saving of the cooling water and energy. Meanwhile, the RA-912 produced 6%(v/v) ethanol in 10% glucose media at $45^{\circ}C$ and showed the less ethanol-tolerance compared with industrial strains. As the produced alcohol was recovered by the vacuum evaporator at $45^{\circ}C$ in 15% glucose media, the final fermentation ratio was enhanced (76% of theoretical yields). This suggest that a hyperproductive process could be achieved by a continuous input of the substrate and continuous recovery of the product under vacuum in high cell-density culture.

• Journal of Applied Biological Chemistry
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• 제63권3호
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• pp.229-234
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• 2020

Beer production with rice or other malt substitutes suffers from a lack of suitable enzymes for saccharification. For this reason, rice nuruk (fermentation starter) was tested as a starch replacement for malt in the saccharification process of beer production. The results of this study show that the enzyme activities of rice nuruk made with brewing fungi were higher than those of malt. Saccharification and glucoamylase activities were high in Aspergillus awamori KCCM 30790 and α-amylase activity was high in Aspergillus oryzae CF1003. Overall, malt beer had significantly higher alcohol, pH, total acid, volatile acids, amino acids, free amino nitrogen, bitterness unit and ΔE than rice nuruk beer. Where as Aspergillus awamori KCCM 30790 beer had significantly higher soluble solids, reducing sugar than malt beer. According to a sensory evaluation, malt beer was better color, flavor and Aspergillus oryzae CF1003 beer was better taste, texture, overall acceptability than other beer. Therefore Aspergillus awamori KCCM 30790 beer was suitable considering enzyme activities (saccharification, glucoalmylase) and physicochemical characteristics (soluble solids, reducing sugar). And then Aspergillus oryzae CF1003 beer was suitable considering sensory evaluation (taste, texture, overall acceptability). Therefore rice nuruk like Aspergillus awamori KCCM 30790 and Aspergillus oryzae CF1003 were suitable as a substitute material that can replace for malt in beer proceccing.

• 한국식품영양과학회지
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• 제23권1호
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• pp.78-89
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• 1994

To evaluate of quality of Yakju brewed with different types of fermenters(Nuruk) and brewed by a method described in Sallymkyungjae, blucoamylase and protease and protease activities of Nuruk were measured, and proximate composition , coloring degree, acetaldehyde , alcohol , , fusel oils , amino acid content , mineral content and sugar composition of Yakju samples were also determined. It was foung that the lower the pH, the lower the glucoamylase acitvity in Nuruk samples A to E . In A, B, D and H, protease activity washigher at ph 5.5 than at pH 5.0 . Yakju sampels 1 to 5 during fermentation , total acidity and amino acid content were high at the first step and were getting lower gradually at the second step. In Yakju samples 6 to 11 , ethanol content was high in 6b, 7b, 8a, 8b and 11b. At the second step, residual sugar content was getting higher gradually in 7 a, 11 a and 11b. The coloring degree of Yakju wasinfluenced by not only color of Nuruk but also Fe content in Yakju . Of the Yakju examined , only 9a and 9b contained acetaldehyde in trace amounts. Thanol content was the highest in 8a and 8b. Fusel oil content was high in 8a and 8b. In samples 6 to 9 , aspartic acid content was higher in treatment a than treatment a than treatment b, but tyrosine , histidine and proline contents were higher in treatment a than treatment b. The levels of frucose, melibiose, sorbitol, and arabinose in Yakju brewed from unsteamed rice were higher than in Yakju brewed from steamed rice. K content was the lowest in 9a and 9b. Na content was higher in treatment a than in treatment a than in treatment b. In only 6a, Ca/P ratio was more than one.

• 동아시아식생활학회지
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• 제27권3호
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• pp.348-363
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• 2017

We analyzed the mixed culture characteristics of isolated brewing fungi obtained from Korean traditional nuruk for their development as fermentation starters. In a previous study, we selected appropriate fungi strains based on their large fungi bodies and strong enzyme activities. These fungi strains were mixed cultured under various combination of ratios, pHs and temperatures. As a result, total acidities of R. delemar mixed culture media were higher than those of A. oryzae cultured at $20^{\circ}C$ and $37^{\circ}C$. The pHs of A. luchuensis 34-1 and A. oryzae 37-7 as well as R. delemar 58-8 and A. oryzae 37-7 mixed culture media gradually increased with the culture period. On the contrary, total acidities of the mixed culture media gradually decreased. ${\alpha}-Amylase$ activities of R. delemar 26-4 and R. oryzae 82-7 mixed culture media were strong at $20^{\circ}C$ and pH 4, glucoamylase activities of R. delemar 58-8 and A. oryzae 37-7 were strong at $37^{\circ}C$, pH 3 and 1:2 ratio, and acidic protease activities of R. delemar 26-4 and A. oryzae 78-5 were strong at $20^{\circ}C$, pH 4 and 1:4 ratio. This study provides the optimal mixed culture conditions for fermentation starters based on changes in pH and total acidity, favorable enzyme activities, and fungi varieties.

• Applied Biological Chemistry
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• 제21권2호
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• pp.123-130
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• 1978

마늘가루 첨가(添加)가 국균(麴菌)의 각종(各種) 효소생산(酵素生産) 및 생육(生育)에 미치는 영향을 규명(糾明)할 목적으로 Asp. oryzae D(단모균(短毛菌))와 Asp. oryzae H(장모균(長毛菌)) 균주를 마늘가루를 함유하는 밀기울배지 및 Czapek-Dox액체배지에 배양하여 각종효소력(酵素力), 균체생성량(菌體生成量), pH, 적정산도(滴定酸度), 환원당 등(等)을 측정한 결과는 다음과 같다. 1, Asp. oryzae D균주의 경우 산성 protease는 마늘가루첨가농도 $0.5{\sim}2%$범위내에서, 중성 protease는 0.5%, alkali성(性) protease는 $2{\sim}6%$범위내에서 각각 대조구에비하여 활성이 높았다. 2, Asp. oryzae H균주의 경우 각(各) protease의 활성은 마늘가루첨가농도 $0.5{\sim}8%$범위내에서는 대조구와 큰차이가 없었으나 30%에서는 peak를 나타냈다. 3. Asp. oryzae H균주의 경우 마늘가루첨가는 $\alpha$ 및 glucoamylase생성을 증가시켰다. 4. 마늘가루첨가는 국균(麴菌)의 cellulase 생성을 저해(沮害)하였다. 5. 국균(麴菌)의 균체생성량(菌體生成量)은 마늘가루첨가농도 $0.5{\sim}6%$범위내에서 대조구에 비하여 증가하는 경향을 나타냈고 장모균(長毛菌)은 단모균(短毛菌)에 비해 증가현상이 현저하였다. 6. 마늘가루첨가농도가 증가함에 따라 Asp. oryzae D균주는 Czapek-Dox액체배양물의 pH를 저하(抵下)시키는 경향을 나타냈으나 Asp. oryzae H균주는 배양물의 pH를 상승시켰다. 7 마늘가루첨가농도가 증가함에 따라 Czapek-Dox 액체배양물의 정적산도(定滴酸度)는 대체로 증가하였다. 8. 마늘가루첨가농도가 10%이상인 밀기울고체(固體)배지 및 Czapek-Dox액체 배지에서는 국균(麴菌)의 생육은 거의 억제되었다. 9. Czapek-Dox액체배양시(時) 환원당의 이용율은 마늘첨가농도 $1{\sim}2%$범위에서 가장 양호하였다.

• 한국식품영양과학회지
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• 제33권3호
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• pp.576-581
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• 2004

좁쌀약주를 열 또는 초고압으로 처리한 후 10∼37$^{\circ}C$에서 64일간 저장하면서 저장기간에 따른 미생물수, 효소활성 및 품질변화를 측정하였다. 열 또는 초고압 처리구의 일반세균 수는 1$0^{\circ}C$와 $25^{\circ}C$에서 약 $10^2$ CFU/mL로 저장기간 동안 큰 변화가 없었지만 37$^{\circ}C$ 저장에서 열 처리구와 상온 초고압처리구는 저장 55일, 고온 초고압처리구는 저장 25일 이후에 검출되지 않았다. 열 또는 초고압 처리구의 젖산균과 효모는 처리 직후 완전히 사멸된 후 모든 저장온도에서 저장기간 내내 검출되지 않았다. $\alpha$-Amylase의 상대활성은 1$0^{\circ}C$에서 저장하는 동안 무처리구와 상온 초고압처리구는 약 100% 이상으로 높은 값을 유지하였으나 열처리구와 고온 초고압처리구는 약 40% 이하로 낮은 값을 유지하였다. 반면 $25^{\circ}C$와 37$^{\circ}C$에서는 무처리구와 상온 초고압처리구의 상대활성이 급격하게 감소하여 열처리구 및 고온 초고압처리구와 비슷한 수준을 유지하였다. 무처리구와 상온 초고압처리구의 glucoamylase 활성은 1$0^{\circ}C$에서는 거의 변화가 없었지만, 저장 온도가 높을수록 감소폭이 더 컸다. 열처리구와 고온 초고압처리구는 1$0^{\circ}C$와 $25^{\circ}C$에서는 저장기간에 따라 활성이 다소 증가하는 양상을 보였으나 37$^{\circ}C$에서는 거의 변화가 없었다. 열처리구와 초고압처리구의 pH는 모든 저장온도에서 저장 기간 동안 변화가 거의 없었다. 열처리구와 초고압처리구의 탁도는 저장기간 동안 저장온도의 증가에 따라 증가하였으나. 무처리구의 탁도는 저장온도 $25^{\circ}C$에서 저장 34일 후부터 급격히 증가하였다. 열처리구와 초고압처리구의 환원당 함량은 저장기간 동안 저장온도의 증가에 따라 증가하였으나, 무처리구의 환원당 함량은 저장온도 $25^{\circ}C$에서 저장 34일 후부터 급격히 감소하였다.