• KSBB Journal
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• 제28권6호
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• pp.366-371
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• 2013

Ethanol productions were performed by separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes using seaweed, Enteromorpha intestinalis (sea lettuce). Pretreatment conditions were optimized by the performing thermal acid hydrolysis and enzymatic hydrolysis for the increase of ethanol yield. The pretreatment by thermal acid hydrolysis was carried out with different sulfuric acid concentrations in the range of 25 mM to 75 mM $H_2SO_4$, pretreatment time from 30 to 90 minutes and solid contents of seaweed powder in the range of 10~16% (w/v). Optimal pretreatment conditions were determined as 75 mM $H_2SO_4$ and 13% (w/v) slurry at $121^{\circ}C$ for 60 min. For the further saccharification, enzymatic hydrolysis was performed by the addition of commercial enzymes, Celluclast 1.5 L and Viscozyme L, after the neutralization. A maximum reducing sugar concentration of 40.4 g/L was obtained with 73% of theoretical yield from total carbohydrate. The ethanol concentration of 8.6 g/L of SHF process and 7.6 g/L of SSF process were obtained by the yeast, Saccharomyces cerevisiae KCTC 1126, with the inoculation cell density of 0.2 g dcw/L.

• 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.

• Journal of Microbiology and Biotechnology
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• 제21권10호
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• pp.1053-1056
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• 2011

Optimal conditions for a high cell density fermentation were investigated in a recombinant Escherichia coli producing salmosin, a platelet aggregation inhibitor. The optimized carbon and nitrogen sources were glycerol 10 g/l, yeast extract 30 g/l, and bacto-tryptone 10 g/l, yielding the dry cell weight (DCW) of 10.61 g/l in a 500 ml flask culture. The late-stage induction with 1% L-arabinose in a 5 l jar fermentor showed the highest DCW of 65.70 g/l after 27 h of the fed-batch fermentation. Around 2,200 mg/l of the protein was expressed as an inclusion body that was then refolded to obtain the active salmosin of 96 mg/l. We also confirmed the inhibitory activity against platelet aggregation of the active salmosin from the high cell density fermentation.

• 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.

• 한국식품과학회지
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• 제17권3호
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• pp.136-140
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• 1985

두께가 서로 다른(5${\sim}$24mm) 레토르트 미반에 대하여 여러온도(110-$150^{\circ}C$)에서 최적품질보유가 가능한 고온살균조건을 컴퓨터 simulation에 의하여 구하였다. 최적조건은 12D의 미생물학적 안전성을 유지할 때 최소의 c-값과 최대의 thiamine retention을 갖는 건에 의하여 선정하였다. 계산결과는 고온일수록 시료두께의 영향이 매우 중요함을 보이면서 미반고온살균의 우수한 음질보유는 두께 10mm이하에서 나타난다.

• Mycobiology
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• 제39권1호
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• pp.20-25
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• 2011

Spores of Aspergillus sp. SU14 were treated repeatedly and sequentially with $Co^{60}$ ${\gamma}$-rays, ultraviolet irradiation, and N-methyl-N'-nitro-N-nitrosoguanidine. One selected mutant strain, Aspergillus sp. SU14-M15, produced cellulase in a yield 2.2-fold exceeding that of the wild type. Optimal conditions for the production of cellulase by the mutant fungal strain using solid-state fermentation were examined. The medium consisted of wheat-bran supplemented with 1% (w/w) urea or $NH_4Cl$, 1% (w/w) rice starch, 2.5 mM $MgCl_2$, and 0.05% (v/w) Tween 80. Optimal moisture content and initial pH was 50% (v/w) and 3.5, respectively, and optimal aeration area was 3/100 (inoculated wheat bran/container). The medium was inoculated with 25% 48 hr seeding culture and fermented at $35^{\circ}C$ for 3 days. The resulting cellulase yield was 8.5-fold more than that of the wild type strain grown on the basal wheat bran medium.

• Applied Biological Chemistry
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• 제51권1호
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• pp.17-23
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• 2008

본 연구는 산머루를 이용한 과실주의 발효시 원료 등에서 기인한 강한 산미에 의한 과실주의 품질을 저하시키는 것을 개선시키기 위하여 혼합균주의 접종에 의한 알코올 발효 과정중 다양한 혼합배양 조건으로 감산발효를 시도하였다. 산머루 알코올 발효균주로 사용된 Saccharomyces sp. SMR-3 배양구에 Schizosaccharomyces pombe와 Schizosaccharomyces japonicus를 각각의 감산발효균주로 접종 후 혼합배양 한 결과, 산머루 알코올 발효균주 Saccharomyces sp. SMR-3에 Schizosaccharomyces pombe를 $22^{\circ}C$, 12일간 혼합 배양한 처리구가 알코올 함량 $15.8{\pm}0.2%$로 최대였고, 산도 $0.44{\pm}0.02%$, 총 유기산 함량 $648.96{\pm}7.14mg%$ , malic acid $99.30{\pm}1.24mg%$ 로 가장 낮게 나타나, 알코올 발효균주 단독으로 배양한 처리구 보다 알코올 함량은 2% 이상 높았고, 산도는 51.65%, 총 유기산은 48.02% 및 malic acid는 81.12%의 감소 효과를 나타내어 최적의 감산발효 조건으로 나타났다.

• Preventive Nutrition and Food Science
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• 제9권3호
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• pp.213-217
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• 2004

We evaluated the possibility of rapid fermentation of anchovy sauce using a commercial protease. The fermentation characteristics were monitored by response surface analysis. The content of total nitrogen was high (around 1 %) with fermentation at 51.7～57.5$^{\circ}C$ after 10.2～16.4 hours, but rapidly decreased at higher temperatures (6$0^{\circ}C$ or over), while the $R^2$ of polynomial equation was 0.9185 (p<0.05). The amino acid content rapidly decreased to approximately 600 mg% and less at high temperature (6$0^{\circ}C$ and over), and the $R^2$ was 0.9578 (p<0.01). The free amino acids were affected more by fermentation time when fermentation temperature was lower, and the $R^2$ for total free amino acids was 0.8496 (p<0.10). The $R^2$ for sweet free amino acids was 0.9144 (p<0.05). According to the results of this study, the optimal conditions for anchovy sauce fermentation were predicted to be 52.5～56.9$^{\circ}C$ and 13.3～16.4 hours, and the predicted values and actual values of each response variable were similar to each other when the fermentation was performed at a random point within the optimal range. Also, the comparison of the quality between the quick anchovy sauce and sauces currently on the market showed that the content of sweet amino acids was higher in the former than in the latter.

• 한국식품과학회지
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• 제23권2호
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• pp.167-174
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• 1991

토양으로부터 생물고분자의 생산균주로 분리한 알칼리 내성 Bacillus sp.의 생물고분자 생산을 위한 최적 배양조건을 검토하였고, 반응 표면분석법에 의한 생산 최적화를 수행하였다. 최대의 생물고분자 생산은 soluble starch 8%, yeast extract 0.75%, $NaNO_3$ 0.1%, $MgSO_4\;7H_2O$ 0.05% 및 $Na_2CO_3$ 1%(pH 10)의 조성배지에서 배양온도 $30^{\circ}C$로 36시간 이상 진탕배양하였을 때 얻어졌으며, 이때의 생물고분자 생산량은 약 44g/l(대당수율로는 약 55%)이었다. C/N비, 온도 및 pH를 독립변수로 한 반응 표면분석에 의한 생물고분자 생산의 최적조건은 C/N비 15.16, 배양온도 $34.62^{\circ}C$ 및 pH 9.50의 정상점에서 얻어졌으며, 이 조건에서 생물고분자의 생산량은 66.84g/l로 추정 되었다.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.781-787
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• 2014

2-Ketogluconic acid production by Klebsiella pneumoniae is a pH-dependent process, strictly proceeding under acidic conditions. Unfortunately, cell growth is inhibited by acidic conditions, resulting in low productivity of 2-ketogluconic acid. To overcome this deficiency, a two-stage fermentation strategy was exploited in the current study. During the first stage, the culture was maintained at neutral pH, favoring cell growth. During the second stage, the culture pH was switched to acidic conditions favoring 2-ketogluconic acid accumulation. Culture parameters, including switching time, dissolved oxygen levels, pH, and temperature were optimized for the fed-batch fermentation. Characteristics of glucose dehydrogenase and gluconate dehydrogenase were revealed in vitro, and the optimal pHs of the two enzymes coincided with the optimum culture pH. Under optimum conditions, a total of 186 g/l 2-ketogluconic acid was produced at 26 h, and the conversion ratio was 0.98 mol/mol. This fermentation strategy has successfully overcome the mismatch between optimum parameters required for cell growth and 2-ketogluconic acid accumulation, and this result has the highest productivity and conversion ratio of 2-ketogluconic and produced by microorganism.