• KSBB Journal
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• 제25권6호
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• pp.539-546
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• 2010

In this work, mass production of Bacillus licheniformis SCD121067 through medium optimization by statistical experimental method was studied. First, galactose, yeast extract and potassium phosphate dibasic were selected as carbon, nitrogen and phosphate sources for mass production of B. licheniformis SCD121067 by using one factor at a time method. Second, according to the result of Plackett-Burman experimental design, key factors was yeast extract and $K_2HPO$. Finally, the response surface methodology was performed to obtain the optimum concentrations of two selected variables. The optimized medium composition consisted of 20 g/L galactose, 36 g/L yeast extract, 0.41 g/L $K_2HPO4$, 0.25 g/L $Na_2CO_3$, 0.4g/L $MgSO_4$ and 0.01g/L $CaCl_2$. Dry cell weight (15.4 g/L) by optimum production medium were increased 10 times, as compared to that determined with basic production medium (1.5 g/L). Fermentation conditions were examined for the mass production of B. licheniformis. The effect of temperature, agitation speed, pH and aeration rate on the mass production of B. licheniformis were also studied in a batch fermenter which was carried out in a 2.5 L bioreactor with a working volume of 1.5 L containing optimized production medium. As a result, dry cell weight of batch culture was 30.7 g/L at $42^{\circ}C$, 300 rpm, pH 8.0 and 2 vvm.

• 한국식품과학회지
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• 제35권4호
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• pp.708-712
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• 2003

내삼투압성 효모인 Candida magnoliae의 발효조건이 erythritol의 생산에 미치는 영향에 대해 조사하였다. 탄소원으로는 포도당보다 sucrose가 우수하였으며, sucrose 400 g/L를 주입하였을 때 109 g/L의 erythritol이 생산되었다. 질소원으로 yeast extract을 사용했을 때, 질소원의 농도가 낮을수록 높은 erythritol 수율을 획득할 수 있었으며, 15 g/L의 yeast extract와 함께 무기질소원인 ammonium phosphate를 3 g/L의 농도로 첨가하므로써, 수율 0.37 g/g, $0.78\;g/L{\cdot}hr$의 생산성으로 149 g/L의 erytnritol을 얻을 수 있었다. KCl을 이용한 높은 삼투압 조건에서의 플라스크 배양 결과, 40 g/L의 농도로 첨가한 경우가 erythritol 생산에 가장 유리하였으며, 이와 같은 실험결과를 발효기 배양에서 검증한 결과, KCl을 40 g/L로 첨가하여 167 g/L의 erythritol을 0.42 g erythritol/g sucrose의 수율로 생산할 수 있었다.

• Food Science and Biotechnology
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• 제18권3호
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• pp.732-738
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• 2009

An acidic polygalacturonase (PG) from Aspergillus kawachii was produced by solid state fermentation employing a polyurethane foam support. The conditions used for the production of acidic PG were particle size of support (0.6 or 500 $mm^3$) and fermentation time. From the factors studied, the particle size had important influence on enzyme production. The best conditions for acidic PG production were $0.6\;mm^3$ particle size, 18 hr at $30^{\circ}C$ and initial pH of 5.0. In addition, pectin was extracted from citrus pomaces (grapefruit, lime, and tangerine) by acidic PG at $50^{\circ}C$ for 24 hr with citric acid solution. Infrared spectroscopy showed that lime pomace had more high-methoxylated (65%) endogenous pectin than was obtained than from grapefruit or tangerine pomaces. The enzymatically extracted pectin yield in dry basis (d.b.) for grapefruit and lime pectins were 6.95 and 4.25%, respectively. The citric acid solution alone also contributed to pectin extraction from citrus pomaces (7-9%, d.b.). Limited pectin extraction by acidic PG from tangerine pomace was most likely due to the presence of low-methoxylated endogenous pectin. The enzymatic method for pectin extraction using acidic PG from A. kawachii is a promising technique for releasing highly polymerized pectic substances from high-methoxylated lime or grapefruit pomaces.

• KSBB Journal
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• 제19권6호
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• pp.478-483
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• 2004

본 연구를 통하여 유기산 생산을 위한 본 연구를 통하여 유기산 생산을 위한 Propionibacterium acidipropionici의 발효 특성을 규명하여 보았다. P. acidipropionici ATCC 25562, 4875, 및 4965 등 세 균주를 선별하여 발효 실험에 의한 최적 성장조건을 규명한 결과, peptone $1.5\%$ (w/v), yeast extract $0.75\%$ (w/v)에서 유기산 생산성이 최대로 나타났다. 또한 주어진 영양 조건에서 온도, pH 등 환경을 제어하며 회분식 발효를 실시한 결과 세 균주 모두 pH 6.0에서 유기산 수율과 생산성이 가장 높았으며, 그 중에서도 P acidipropionci ATCC 4965 균주가 유기산 생산성이 0.29 g total acids/L/h로 가장 우수한 것으로 판명 되었다. 세 균주의 화학양론적인 유기산 생산비를 비교해본 결과 1.5몰의 글루코오스로부터 $1.60{\sim}2.34$몰의 프로피온산과 $0.74{\sim}1.05$몰의 초산을 생산하는 것으로 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권1호
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• pp.72-81
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• 2019

Objective: To determine the effect of gut pH and rumen microbial fermentation on glycerol encapsulated in alginate and alginate-chitosan polymers. Methods: Glycerol was encapsulated at 2.5%, 5%, 7.5%, or 10% (w/w) with sodium alginate (A) and alginate-chitosan (AC) polymers. Surface morphology and chemical modifications of the beads were evaluated using scanning electron microscopy and Fourier transform infrared (FTIR) spectra. Encapsulation efficiency was determined at the 5% glycerol inclusion level in two experiments. In experiment 1, 0.5 g of alginate-glycerol (AG) and alginate-chitosan glycerol (ACG) beads were incubated for 2 h at $39^{\circ}C$ in pH 2 buffer followed by 24 h in pH 8 buffer to simulate gastric and intestinal conditions, respectively. In experiment 2, 0.5 g of AG and ACG beads were incubated in pH 6 buffer at $39^{\circ}C$ for 8 h to simulate rumen conditions. All incubations were replicated four times. Free glycerol content was determined using a spectrophotometer and used to assess loading capacity and encapsulation efficiency. An in vitro experiment with mixed cultures of rumen microbes was conducted to determine effect of encapsulation on microbial fermentation. Data were analyzed according to a complete block design using the MIXED procedure of SAS (SAS Institute, Cary, NC, USA). Results: For AG and ACG, loading capacity and efficiency were 64.7%, 74.7%, 70.3%, and 78.1%, respectively. Based on the FTIR spectra and scanning electron microscopy, ACG treatment demonstrated more intense and stronger ionic bonds. At pH 6, 36.1% and 29.7% of glycerol was released from AG and ACG, respectively. At pH 2 minimal glycerol was released but pH 8 resulted in 95.7% and 93.9% of glycerol released from AG and ACG, respectively. In vitro microbial data show reduced (p<0.05) fermentation of encapsulated glycerol after 24 h of incubation. Conclusion: The AC polymer provided greater protection in acidic pH with a gradual release of intact glycerol when exposed to an alkaline pH.

• Journal of Microbiology and Biotechnology
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• 제32권1호
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• pp.117-125
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• 2022

Until recently, four types of cellobiose-fermenting Saccharomyces cerevisiae strains have been developed by introduction of a cellobiose metabolic pathway based on either intracellular β-glucosidase (GH1-1) or cellobiose phosphorylase (CBP), along with either an energy-consuming active cellodextrin transporter (CDT-1) or a non-energy-consuming passive cellodextrin facilitator (CDT-2). In this study, the ethanol production performance of two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-2 (N306I) with GH1-1 or CBP were compared with two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-1 (F213L) with GH1-1 or CBP in the simultaneous saccharification and fermentation (SSF) of cellulose under various conditions. It was found that, regardless of the SSF conditions, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the best ethanol production among the four strains. In addition, during SSF contaminated by lactic acid bacteria, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the highest ethanol production and the lowest lactate formation compared with those of other strains, such as the hydrolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-1 with GH1-1, and the glucose-fermenting S. cerevisiae with extracellular β-glucosidase. These results suggest that the cellobiose-fermenting yeast strain exhibiting low energy consumption can enhance the efficiency of the SSF of cellulosic biomass.

• Journal of Microbiology and Biotechnology
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• 제6권3호
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• pp.202-208
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• 1996

In order to investigate fermenting conditions and the microorganisms necessary for factory production of traditional Korean soy sauce, we manufactured soy sauce made by Bacillus species SSA3-2M1 and fused ST723-F31 with aeration (1/30 vvm, 113 vvm and 2/3 vvm) at $30^{\circ}C$ for 40 days. This method was chosen to investigate the changes of dissolved oxygen, pH, cell number, flavor and the taste components during fermentation. When air was supplied (2/3 vvm) to the fermentor during fermentation, the flavor of the soy sauce and the composition of taste components (free amino acids, free sugars and organic acids) were similar to that of traditional Korean soy sauce after 22 days. The results of our experiments indicates that the mass production of traditional Korean soy sauce is possible using Bacillus species SSA3-2M1 and fused ST723-F31 given sufficient aeration.

• KSBB Journal
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• 제7권2호
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• pp.126-131
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• 1992

P. shermanii IFO 1239을 이용 vitamin $B_{12}$를 생산할 때 산소의 영향은 매우 큼 것으로 나타났는데 배양 전반부는 혐기적 조건이, 후반부는 호기적 조건이 vitamin $B_{12}$ 생성증진에 효과적임이 밝혀졌다. 본 연구를 통하여 배양 48시간 동안은 복합배지상에서 혐기적으로 배양하다가 48시간 이후부터는 합성배지로 바꾸고 호기적 조건으로 배양해주는 방법이 vitamin $B_{12}$ 의 생성을 증가시켰다. 이런 배양방법을 이용하여 탄소원과 유기산이 vitamin $B_{12}$ 생성에 미치는 영향을 알아본 결과 glucose, fructose, lactose가 좋은 탄소원이었으며 유기산 중에서는 succinate 와 malate가 각각 34.9%와 18.7%의 vitamin $B_{12}$생성을 촉진시켰다.

• 한국식품과학회지
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• 제3권1호
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• pp.64-67
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• 1971

장메주의 Protease activity는 54시간 발효시(醱酵時)에 가장 높았고 (Fig. 1) 유리아미노태질소(態窒素)는 $36{\sim}42$시간에서 가장 많이 유리되었으며 총산(總酸)은 24시간에서 제일 많았다. 수분(水分)이 많은 청국장은 적은 것에 비(比)하여 아미노태질소(態窒素)의 유리양이 많았고 그후에는 감소(減少)되었으나 5일까지는 거의 같게 증가되어 peak를 이루었다. 청국장의 총산(總酸)은 20일까지 계속 증가했고 그후에는 서서히 증감(增減)했으며 수분(水分)이 많은 것이 작은 것보다 총산(總酸)이 현저히 많았다.(Table 2) 숙성도(熟成度)와 총산량(總酸量)으로 보아 청국장의 수분함량(水分含量)은 55%가 좋았다.

• 한국미생물·생명공학회지
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• 제27권4호
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• pp.327-332
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• 1999

A highly productive fed-batch fermentation process was developed for the production of L-ornithine by using a new stabilized strain, Breviabcterium ketoglutamicum BK52. Fed-batch cultures with a continuous feeding of the complex medium were conducted on various operating conditions. The optimal concentration of phosphate in the complex medium was 2.1g/L. The optimal feeding rate of L-arginine was 0.028g/L/hr. The optimal feeding point of the complex medium was determined to be at 40 OD of the cell mass. The final L-ornithine concentrations within 64hrs of cultivation in 5 and 50 liter fermenters were 73g/L and 71g/L, respectively. The maximum overall L-ornithine productivity was 1.14g/L/hr which was about 2 times higher than that of the conventional fed-batch culture with intermittent feeding. The overall productivity of the fermentation system is remarkably improved by employing the optimized conditions, and it offers a significant potential for industrial application.