• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.319-323
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• 2005

This study is concerned with development of efficient culture methods for lactic acid fermentation of Lactobacillus sp. RKY2. The cell-recycle repeated batch fermentation using cheese whey and corn steep liquor as raw materials was tried in order to further enhance the productivity of lactic acid. In addition, fermentation efficiencies could be considerably enhanced by cell-recycle continuous culture. Through the cell-recycle repeated batch fermentation, lactic acid productivity was maximized to 6.34 $g/L{\cdot}h,$ which corresponded to 6.2 times higher value than that of the batch fermentation. During the cell-recycle continuous fermentation, the last dry cell weight at the end of fermentation could be increased to 25.3 g/L.

• Journal of Dairy Science and Biotechnology
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• 제35권4호
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• pp.249-254
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• 2017

The purpose of this study was to investigate the acid tolerance, bile acid tolerance, and fermentation activity of lactic acid bacteria isolated from Kimchi in the presence of hydrolysates of whey protein concentrate. Kimchi isolates DK109, DK119, DK121, DK128, DK211, DK212, and DK215, which were identified as Lactobacillus sp., and L. casei DK128 showed the highest acid and bile acid tolerance. To produce whey hydrolysates, enzymes were added to a 10% (w/v) whey protein concentrate (WPC) solution at 1:50 (w/v, protein). The viabilities of the DK strains were determined in the presence of low pH and bile salts. Then, yogurt was produced via fermentation with L. casei DK128, an isolate from Kimchi, in the presence of the following additives: CPP, WPC, and WPC hydrolysates (WPCH) generated by alcalase (A) or neutrase (N). The produced yogurts were subjected to various analyses, including viable cell counts (CFU/mL), pH, titratable activity, and sensory testing. After 8 h of fermentation, the pH and titratable activity values of all test samples were 4.2 and 0.9, respectively. The viable counts of LAB were $3.49{\times}10^8$, $5.72{\times}10^8$, $7.01{\times}10^8$, and $6.97{\times}10^8$, for the Control, CPP, A, and N samples, respectively. These results suggest that whey proteins have potential as dietary supplements in functional foods and that WPCH could be used in yogurt as a low-cost alternative to CPP.

• Journal of Microbiology and Biotechnology
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• 제2권2호
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• pp.108-114
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• 1992

The fermentative characteristics in ethanol production from lactose, with increased ethanol tolerance, of a fusant yeast strain constructed by protoplast fusion of Saccharomyces cerevisiae and Kluyveromyces fragilis were studied. The ethanol tolerance of this strain was increased to 8.0%, compared with the parent K. fragilis. During batch ethanol fermentation the optimal cultivation conditions for this fusant yeast were an initial pH of 4.5, a culture temperature $30^\circ{C}$. stirring at 100 rpm without aeration in 10% lactose medium (supplied with 1.0% yeast extract). Using this fusant strain in whey fermentation to ethanol, maximum ethanol production reached 3.41% (w/v) (theoretical yield; 66.7%) after a 48 hour cultivation period.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.291-294
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• 2000

The production of polyhydroxybutrate(PHB) by Alcaligenes eutrophus NCIB 11599 was studied in a synthetic medium from whey as a sole carbon source. Especially pH-effect was treated and compared in this study. At the end of fermentation (A) unadjusted to pH, the dry cell weight, PHB concentration, and PHB conversion rate were 10.3g/L, 3.1g/L, and 30%, respectively. At the end of fermentation (B) adjusted to $pH(7.0{\sim}7.5)$, the dry cell weight, PHB concentration, and PHB conversion rate were 12.5g/L, 4.8g/L, and 41%, respectively. PHB conversion rate was about 10% higher on the fermentation (B) than on the fermentation (A).

• 한국축산식품학회지
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• 제35권2호
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• pp.189-196
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• 2015

The aim of this study was to manufacture functional high protein fermented beverage, using whey protein concentrate (WPC) and Lactobacillus plantarum DK211 isolated from kimchi, and to evaluate the physicochemical, functional, and sensory properties of the resulting product. The fermented whey beverage (FWB) was formulated with whey protein concentrate 80 (WPC 80), skim milk powder, and sucrose; and fermented with Lactobacillus plantarum DK211 as single, or mixed with Lactococcus lactis R704, a commercial starter culture. The pH, titratable acidity, and viable cell counts during fermentation and storage were evaluated. It was found that the mixed culture showed faster acid development than the single culture. The resulting FWB had high protein (9%) and low fat content (0.2%). Increased viscosity, and antioxidant and antimicrobial activity were observed after fermentation. A viable cell count of 10⁹ CFU/mL in FWB was achieved within 10 h fermentation, and it remained throughout storage at 15℃ for 28 d. Sensory analysis was also conducted, and compared to that of a commercial protein drink. The sensory scores of FWB were similar to those of the commercial protein drink in most attributes, except sourness. The sourness was highly related with the high lactic acid content produced during fermentation. The results showed that WPC and vegetable origin lactic acid bacteria isolated from kimchi might be used for the development of a high protein fermented beverage, with improved functionality and organoleptic properties.

• Journal of Dairy Science and Biotechnology
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• 제32권2호
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• pp.111-119
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• 2014

다양한 기능성을 갖는 유청과 표고버섯을 혼합한 기능성 음료를 개발해 유청의 활용 범위를 높이고자, 유청과 표고버섯을 혼합하여 유산균 발효를 시킨 다음, 발효 전 후 성분 비교, 항산화 활성 평가 및 관능검사 등을 실시한 결과는 다음과 같다. 표고버섯 첨가량에 따른 pH 변화는 버섯 첨가량이 증가할수록 약간 감소하는 경향을 보였으나, 시료구별 큰 유의적인 차이를 보이지 않았다. 산도는 표고버섯 첨가량이 증가할수록 높아지는 걸 확인하였다. 표고버섯 첨가 유청 발효액의 유산균수는 $10^{11}$까지 확인되어 유산균 음료로의 가능성을 확인하였다. 발효 전 유청과 발효 후 유청 발효액의 단백질 함량은 유의적인 차이를 보이지 않았고, 지방 함량은 0.31%에서 0.63%로 발효 후 유청 발효액이 약 2배 정도 증가하였다. 유리당은 lactose의 경우, 발효 전 4.83%에서 발효 후 2.48~2.61%로 급격히 감소하였다. 유리아미노산 함량은 발효 전 유청은 196.7 mg%였고, 발효 후 유청 발효액의 경우 260.16~462.16 mg%로 함량이 증가하였다. 발효 전 후 DPPH radical 소거 활성은 유산균 접종 후 즉시 측정한 값과 비교해, 발효 24시간째 측정한 값이 모든 시료구에서 높게 나타났다. ABTS radical 소거 활성은 DPPH radical 소거 활성 측정 결과와 마찬가지로 발효한 시료가 발효 전 시료에 비해 활성이 매우 높게 나타났다. 발효 전 후 산화질소 생성량은 발효 후의 산화질소 생성량이 발효 전의 산화질소 생성량에 비해 낮아지는 경향을 보였다. 유청 발효액의 관능평가 결과는 색, 맛 및 종합기호도 항목에서는 1.0% 첨가구에서 4.7, 4.5 및 4.8로 가장 높은 기호도를 보였다. 유청 발효액의 브랜딩을 통한 유청 음료의 관능평가 결과, 브랜딩 후 유청 음료는 7~8점 정도의 기호도를 보여 음료로써의 기호도 값을 확보하였다. 표고버섯향 첨가량에 따른 기호도를 보면 0.01% 첨가 시료구에서 모든 항목의 기호도가 높게 나타났다.

• 한국조리학회지
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• 제13권1호
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• pp.55-61
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• 2007

L. acidophilus KCCM 32820과 P. freudenreichii KCCM 31227의 성장곡선 및 5%와 10% 유청 배지를 고압증기멸균 및 저온살균하여 L. acidophilus KCCM 32820과 P. freudenreichii KCCM 31227을 혼합배양시 생성되는 propionic acid와 acetic acid 양을 측정하였다. L. acidophilus KCCM 32820의 대수기는 $6\sim21$시간, P. freudenreichii KCCM 31227의 대수기는 $36\sim108$시간으로 나타났다. 혼합배양시 propionic acid의 생성량은 5% 유청 배지보다는 10% 유청 배지에서, 고압증기 멸균보다는 저온살균에서 많은 양이 생성되었다. Propionic acid의 최대 생산량은 10% 유청 배지를 저온살균하였을 때 배양 120시간에 7.88 mg/mL이었다. Acetic acid도 5%보다는 10% 유청 배지에서 높은 생성량을 나타냈고 그 생성량은 배양시간이 경과함에 따라 propionic acid 생성량의 $2:1\sim3:1$이었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.181-185
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• 2005

We investigated the fermentative production of lactic acid from cheese whey and corn steep liquor as cheap raw materials using Lactobacillus sp. RKY2 to reduce the manufacturing cost of lactic acid. Lactic acid yields were obtained at more than 0.98 g/g from medium containing whey lactose. Lactic aid productivities and yields obtained from whey lactose were slightly higher than those obtained from pure lactose. The final concentration of lactic acid increased with increase, in whey lactose concentration, whereas the lactic acid productivity decreased probably due to substrate inhibition. The fermentation efficiencies were improved by addition of more corn steep liquor to the medium.

• Applied Biological Chemistry
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• 제50권1호
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• pp.6-11
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• 2007

P. freudenreichii KCCM 31227을 whey 배지에서 배양시 whey 배지의 살균방법 즉, 고압증기멸균(121$^{\circ}C$, 15분), 저온살균(60$^{\circ}C$, 30분) 방법과 배양액에 yeast extract를 0.5, 1% 첨가하였을 때 생균수와 총산도를 측정하여 P. freudenreichii KCCM 31227의 생육특성을 조사하였다. 6% whey 배지보다는 12% whey 배지에서, yeast extract 0.5% 보다는 1.0% 첨가 시 생균수가 높았고, 12% whey 배지에 yeast extract를 1.0% 첨가하고 저온살균하였을 때 배양 72시간에 7.5${\times}10^7$ cfu/ml로 가장 높은 생균수를 나타냈다. 총산도는 12% whey 배지에 yeast extract를 1.0% 첨가하여 저온살균하였을 때 5.2로 가장 높았다. 배양 72시간 동안 생균수와 총산도의 증가는 유사한 경향을 보여주었다. Propionic acid와 acetic acid의 생성은 고온살균보다 저온살균에서 높게 검출되었다.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.46-52
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• 1992

농축유청으로부터 유청음료 제조를 위한 최적조건을 조사하기 위해 역삼투장치(reverse osmosis system)를 사용하여 치즈유청 속의 유당을 농축한 수 $\beta$-D-glactosidase로 가수분해시켜 그 분해정도를 HPLC(high performance liquid chromatography)로 측정하였다. 유당의 가수분해 정도는 농축적 유청, 2배 농축 유청과 3배 농축 유청 순으로 가수분해되었고 일정량의 효소첨가에 의해 농축된 염이 $\beta$-D-Galactosidase에 대한 약간의 저해작용을 일으켰다.