• Biotechnology and Bioprocess Engineering:BBE
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• 제9권4호
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• pp.297-302
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• 2004

A chitinase-producing bacterium was isolated from seashore mud around Beobseongpo in Chunmam province through the use of a selective enrichment culture. The best chitinase producing strain was isolated and identified as Serratia marcescens KY from its characteristics. For effective production of chitinase, optimum pH, temperature, and agitation speed were investigated in flask cultures. The optimum pH using Serratia marcescens KY was between pH 6 and 7 and the chitinase produced was 37.9 unit/mL. On the other hand, the optimal pH of the Serratia marcescens ATCC 27117 was 7.5, and the produced amount of chitinase was 35.2 unit/mL. The optimal temperature for chitinase production for Serratia marcescens KY and Serratia marcescens ATCC 27117 was $30^{\circ}$. The cell growth pattern at different temperature was almost identical to the chitinase production. To investigate the optimal shaking speed under optimal culture, speeds were varied in the range of 0∼300 rpm. The maximum production of chitinase was carried at 200 rpm although the cell growth was the highest at 150 rpm. It indicates that oxygen adjustment is required for the maximum chitinase production. Using optimal conditions, batch cultures for comparing Serratia marcescens KY and Serratia marcescens ATCC 27117 were carried out in a 5 L fermentor. The oxygen consumption was increased with the increase of culture. Especially, at 120 h of culture Serratia marcescens KY and Serratia marcescens ATCC 27117 produced 38.3 unit/mL, and 33.5 unit/mL, respectively.

• Mycobiology
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• 제42권3호
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• pp.249-255
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• 2014

We evaluated a more practical and cost-effective immobilization carriers for ethanol production using the yeast Saccharomyces cerevisiae. Three candidate materials-rice hull, rice straw, and sawdust-were tested for their cell-adsorption capacity and operational durability. Derivatizations of rice hull, rice straw, and sawdust with the optimal concentration of 0.5 M of 2-(diethylamino)ethyl chloride hydrochloride (DEAE HCl) resulted in > 95% adsorption of the initial yeast cells at 2 hr for DEAE-rice hull and DEAE-sawdust and in only approximately 80% adsorption for DEAE-rice straw. In addition, DEAE-sawdust was found to be a more practical carrier for immobilizing yeast cells in terms of operational durability in shaking flask cultures with two different speeds of 60 and 150 rpm. Furthermore, the biosorption isotherms of DEAE-rice hull, -rice straw, and -sawdust for yeast cells revealed that the $Q_{max}$ of DEAE-sawdust (82.6 mg/g) was greater than that of DEAE-rice hull and DEAE-rice straw. During the 404-hr of continuous column reactor operation using yeast cells immobilized on DEAE-sawdust, no serious detachment of the yeast cells from the DEAE-sawdust was recorded. Ethanol yield of approximately 3.04 g/L was produced steadily, and glucose was completely converted to ethanol at a yield of 0.375 g-ethanol/g-glucose (73.4% of the theoretical value). Thus, sawdust is a promising practical immobilization carrier for ethanol production, with significance in the production of bioethanol as a biofuel.

• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.828-834
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• 2010

An ethanol-producing yeast strain, CHFY0201, was isolated from soil in South Korea using an enrichment technique in a yeast peptone dextrose medium supplemented with 5% (w/v) ethanol at $30^{\circ}C$. The phenotypic and physiological characteristics, as well as molecular phylogenetic analysis based on the D1/D2 domains of the large subunit (26S) rDNA gene and the internally transcribed spacer (ITS) 1+2 regions, suggested that the CHFY0201 was a novel strain of Schizosaccharomyces pombe. During shaking flask cultivation, the highest ethanol productivity and theoretical yield of S. pombe CHFY0201 in YPD media containing 9.5% total sugars were $0.59{\pm}0.01$ g/l/h and $88.4{\pm}0.91%$, respectively. Simultaneous saccharification and fermentation for ethanol production was carried out using liquefied cassava (Manihot esculenta) powder in a 5-l lab-scale jar fermenter at $32^{\circ}C$ for 66 h with an agitation speed of 120 rpm. Under these conditions, S. pombe CHFY0201 yielded a final ethanol concentration of $72.1{\pm}0.27$ g/l and a theoretical yield of $82.7{\pm}1.52%$ at a maximum ethanol productivity of $1.16{\pm}0.07$ g/l/h. These results suggest that S. pombe CHFY0201 is a potential producer for industrial bioethanol production.

• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.110-116
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• 2010

Lactic acid (LA) fermentation by Lactobacillus salivarius ATCC 11741 immobilized on loofa sponge (LS) was evaluated. To increase the surface area of LS for cell immobilization, $H_2O_2$ and chitosan were introduced as surface modifying reagents. Four chitosans of different molecular weights were separately coated on LS. All experiments were conducted in shaking flask mode at 100 rpm rotating speed and $37^{\circ}C$ with 5% $CaCO_3$ as a pH regulating agent. The effects of initial glucose concentration were investigated in the range of 20-100 g/l on LA fermentation by free cells. The results indicate that the maximum concentration of LA was produced with 50 g/l glucose concentration. The immobilized cell system produced 1.5 times higher concentration than free cells for 24 h of fermentation. Moreover, immobilized cells can shorten the fermentation time by 2-fold compared with free cells at the same level of LA concentration. At 1% (w/v) chitosan in 2% (v/v) acetic acid, the Yp/s and productivities of various molecular weights of chitosans were insignificantly different. Repeated batch fermentations showed 5 effective recycles with Yp/s and productivity in the range of 0.55-0.85 and 0.90-1.20 g/l.h, respectively. It is evident that immobilization of L. salivarius onto LS permits reuse of the system under these fermentation conditions. Scanning electron micrographs indicated that there were more intact cells on the chitosan-treated LS than on the untreated LS, thus confirming the effectiveness of the LS-chitosan combination when being utilized as a promising immobilization carrier for LA fermentation.

• Journal of Microbiology and Biotechnology
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• 제25권3호
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• pp.366-374
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• 2015

Herein, we established a repeated-batch process for ethanol production from glycerol by immobilized Pachysolen tannophilus. The aim of this study was to develop a more practical and applicable ethanol production process for biofuel. In particular, using industrial-grade medium ingredients, the microaeration rate was optimized for maximization of the ethanol production, and the relevant metabolic parameters were then analyzed. The microaeration rate of 0.11 vvm, which is far lower than those occurring in a shaking flask culture, was found to be the optimal value for ethanol production from glycerol. In addition, it was found that, among those tested, Celite was a more appropriate carrier for the immobilization of P. tannophilus to induce production of ethanol from glycerol. Finally, through a repeated-batch culture, the ethanol yield (Y_e/g) of 0.126 ± 0.017 g-ethanol/g-glycerol (n = 4) was obtained, and this value was remarkably comparable with a previous report. In the future, it is expected that the results of this study will be applied for the development of a more practical and profitable long-term ethanol production process, thanks to the industrial-grade medium preparation, simple immobilization method, and easy repeated-batch operation.

• 한국미생물·생명공학회지
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• 제8권2호
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• pp.119-123
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• 1980

누룩으로부터 사상균을 분리하여 우수한 색소 생산균주를 선별하였고 이를 형태학적으로 분지 동정하였다. 배양조건으로 pH, 탄소원, 질소원, 무기염류, 통기효과 및 배양기간 등이 황색 색소 생산에 미치는 영향을 조사하여 다음과 같은 결론을 얻었다. 1. 선별된 색소 생산 균주를 형태학적으로 균사에 격벽과 균사체 끝에 피자기를 가지고 자낭포자와 분생포자를 형성하며 후막포자가 있는 Monascus 속으로 동정 되었다. 2. 색소생산의 최적 PH는 4.5 부근이었으며 질소원으로 yeast extract 0.2%, 탄소원으로 sucrose 3 % 첨가가 양호하였다. 무기염류에 대한 영향으로 KH$_2$PO$_4$및 MgSO$_4$.7$H_2O$ 0.1% 첨가가 좋았으며 통기효과는 75/500m1 (v/v) 배양기간은 3일이 적합하였다.

• KSBB Journal
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• 제11권4호
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• pp.398-404
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• 1996

전세포 효소 고정화 캡슐을 제조하기 위하여 Eschericia coli를 calcium alginate 캡슐내부에 접종하고 배양하였다. E. coli의 캡슐내부 건조중량이 1OOg/L에 달하였다. 생산배지에서 배양하는 동안 캡슐내부에 축적되는 미생물의 양이 많을수록 캡슐 내부에 축적되는 $\beta$galactosidase의 활성도 높았다. 생산배지에 금속이온 $Zn^{+2}를 2{\times}10^{-4} M $ 첨가함으로써 캡슐내부에 축척되는 ${\beta}$-galactosidase의 활성 을 25% 증가시킬 수 있었다. 캡슐제조시 해바라기유를 부피비로 2% 첨가함으로써 캡슐내부에 축적되 는 ${\beta}$-galactosidase의 활성을 10% 증가시킬 수 었었다. 부피산소전달계수, $k_La가 2.55h^- $ 안 플라스크 대신 $k_La가 82h^- $인 concentric air lift reactor 내에서 고정화 E. coli를 배양호농로써 캡슐내부의 전세포${\beta}$-galactosidase의 활성을 86% 증가시킬 수 있었다.

• 미생물학회지
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• 제50권1호
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• pp.84-86
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• 2014

길항균을 생물 농약으로 개발하기 위해서는 저렴한 산업용 배지를 이용한 대량 생산 체계를 확립하는 것이 중요하다. 본 연구에서는 풋마름병 방제 효과가 뛰어난 Bacillus amyloliquefaciens SKU-78 균주의 배양조건을 확립하였다. 저가의 산업용 기질로는 콩가루와 옥수수 전분 배지가 균 생장에 가장 효과적이었고, 최초 pH 5.5, 배양 온도 $30^{\circ}C$, 교반속도 150-250 rpm의 조건으로 30 L fermenter를 이용한 배양에서 20 시간째에 최대 생균수($1.2{\times}10^{11}$ CFU/ml)에 도달하였다. 저가의 산업용 배지로 배양한 배양액을 관주 처리하였을 때 65%의 발병 억제 효과를 나타냄으로써 SKU-78 균주의 산업용 배지를 이용한 대량배양의 기초가 마련되었다.

• 한국식품과학회지
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• 제24권5호
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• pp.451-455
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• 1992

Monascus anka albidus 균사를 쌀가루 7%, $NH_4NO_3$ 0.15%, $KH_2PO_4$ 0.05% 및 $MnSO_4$ 0.1%, 조성의 초기 pH 6.0으로 조절한 배지에 접종하여 $30^{\circ}C$에서 5일간 진탕 배양 하였을 때 가장 높은 색소 생산을 보였다. 특히 탄소원으로써 찹쌀가루가 제일 좋았으며 동시에 질소원으로써 $NH_4NO_3$, 인산염으로는 $KH_2PO_4$가 가장 우수하였으며 최적 C : N율은 18 : 1로 나타났다. 상기 조건에서 색소 생산은 플라스크에서 2.6mg/ml을, 그러나 5l 발효조에서 약 70%인 1.8mg/ml을 생산하였다.

• 한국식품영양과학회지
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• 제27권2호
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• pp.252-258
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• 1998

Biosurfactant를 생산하는 미생물을 토양으로부터 분리하였다. 그 중에서 표면장력 및 계면장력 감소능에서 가장 우수한 L-417주를 순수분리하여 동정한 결과, No-Cardia속으로 판명되었다. Biosurfactant 생산을 위한 최적 배지조성은 3% n-hexadecane, 0.1% $NaNO_3$, 0.02% $K_2HPO_4$, 0.01% $KH_2PO_4$, 0.01% $MgSO_4 \;.\;7H_2O$, 0.01% $CaCl_2$ 0.02% yeast extract였으며, 최적 온도와 pH는 각각 $30^{\circ}C$와 6.0이였다. 이러한 조건에서 500ml용 shaking flask에 최적 배지 50ml를 넣어 배양했을 경우 대수증식기 말기인 4일째에 균의 증식과 유화활성이 가장 높게 나타남에 따라 Nocardia sp. L-417에 의한 bio-surfactant의 생산은 균의 생육과 밀접한 관련이 있는 것으로 판단된다. 이계면활성제는 산업적으로 널리 사용되는 bunker A, paraffin, corn oil 및 oilve oil 등에 대해서도 비교적 높은 유화활성을 나타내였다.