• Journal of Microbiology and Biotechnology
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• 제20권4호
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• pp.718-726
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• 2010

A selected fungal strain, for production of the raw-starchdigesting enzyme by solid-state fermentation, was improved by two repeated sequential exposures to ${\gamma}$-irradiation of $Co^{60}$, ultraviolet, and four repeated treatments with Nmethyl-N'-nitrosoguanidine. The mutant strain Aspergillus sp. XN15 was chosen after a rigorous screening process, with its production of the raw-starch-digesting enzyme being twice that of usual wild varieties cultured under preoptimized conditions and in an unsupplemented medium. After 17 successive subculturings, the enzyme production of the mutant was stable. Optimal conditions for the production of the enzyme by solid-state fermentation, using wheat bran as the substrate, were accomplished for the mutant Aspergillus sp. XN15. With the optimal fermentation conditions, and a solid medium supplemented with nitrogen sources of 1% urea and 1% $NH_4NO_3$, 2.5 mM $CoSO_4$, 0.05% (v/w) Tween 80, and 1% glucose, the mutant Aspergillus sp. XN15 produced the raw-starch-digesting enzyme in quantities 19.4 times greater than a typical wild variety. Finally, XN15, through simultaneous saccharification and fermentation of a raw rice corn starch slurry, produced a high level of ethanol with $Y_{p/s}$ of 0.47 g/g.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.85-90
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• 1992

Saccharomyces속 효모를 사용하여 미강을 배지로 하여 에탄올을 발효특성을 조사하였다. 액화효소와 당화효소를 전처리한 미강에서 여러 Saccharomyces속 효모들을 배양한 결과 Saccharomyces cerevisiae IFO 2346이 높은 에탄올 생성 및 유리아미노산 함량을 나타내었다. 균체성장은 발효 24시간에 $3\times 10^8$cell/ml로 증가하였으며, 발효 72시간후 4.7의 에탄올을 생성하였다. 유리아미노산 총량은 발효과정중 1,099mg/l에서 829mg/l로 감소하였으나, glutamic acid, histidine 및 isoleucine은 오히려 각각 218%, 31%5 및 1%48로 증가하였다.

• Journal of Microbiology
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• 제44권3호
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• pp.276-283
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• 2006

The thermophilic fungus Thermoascus aurantiacus 179-5 produced large quantities of a glucosidase which preferentially hydrolyzed maltose over starch. Enzyme production was high in submerged fermentation, with a maximal activity of 30 U/ml after 336 h of fermentation. In solid-state fermentation, the activity of the enzyme was 22 U/ml at 144 h in medium containing wheat bran and 5.8 U/ml at 48 h when cassava pulp was used as the culture medium. The enzyme was specific for maltose, very slowly hydrolyzed starch, dextrins (2-7G) and the synthetic substrate (${\alpha}$-PNPG), and did not hydrolyze sucrose. These properties suggest that the enzyme is a type II ${\alpha}$-glucosidase. The optimum temperature of the enzyme was $70^{\circ}C$. In addition, the enzyme was highly thermostable (100% stability for 10 h at $60^{\circ}C$ and a half-life of 15 min at $80^{\circ}C$), and stable within a wide pH range.

• 농업과학연구
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• 제4권2호
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• pp.173-177
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• 1977

3종(種)의 효모(酵母)를 시험균주(試驗菌株)로 사용(使用)하여 효모(酵母)의 산(酸) 및 알콜생성(生成)에 미치는 발효조건(醱酵條件)의 영향(影響)을 검토(檢討)하였다. 시험결과(試驗結果)는 다음과 같다. 1. 3균주(菌株)는 모두 혐기적조건(嫌氣的條件)에서보다 배지면(培地面)에 공기(空氣)가 닿아있는 호기적조건(好氣的條件)에서 산성성(酸性成)과 알콜생성(生成)($CO_2$ 발생(發生))이 많았다. 2. 반합성배지(半合成培地)의 경우에 비(比)하여 료배지에서는 산(酸)과 알콜의 생성(生成)이 속(速)히 이루어졌으며 최고치(最高値)에 이르는 시간(時間)이 짧았다. 3. 료배지의 경우에는 혐기적(嫌氣的) 또는 호기적(好氣的)의 어느 조건(條件)에서도 산성성량(酸性成量)의 순위(順位)는 No. 239>No.7>No.47로 되었으며 알콜생성량(生成量)의 순위(順位)는 No. 47>No. 239>No. 7로 되었다. 4. No. 239균(菌)은 산화능(酸化能)이 강(强)할 뿐만 아니라 발효능(醱酵能)도 상당(相當)히 강(强)하므로 다산성(多酸性)의 양조주제조(釀造酒製造)에 이용(利用)할 수 있다고 생각된다.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.443-449
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• 1999

Bacillus subtilis BK-17 which produces a novel protease with fibrinolytic activity was isolated from soybean paste. Bioreactor production of the enzyme was studied in order to optimize fermentation conditions such as medium concentration, pH, agitation speed, and temperature. Under most cultural conditions, enzyme production initially began when the cell growth stopped. The onset of the enzyme production was indicated by rapid increase in both dissolved oxygen (DO) and pH. Two- to three-times more concentrated medium than the flask optimum medium yielded higher enzyme production in the bioreactor fermentation. When the medium pH was controlled constant, pH 6.5 exhibited the highest activity in the range of 6.0 to 7.5, but the activity was similar to the case when the pH was initially adjusted to 7.5 and subsequently maintained within a relatively wide range of 6.4 to 7.8. Agitation speed did not affect the enzyme production with an exception of DO reaching zero. Fermentation time was reduced when temperature increased within the range of $25^{\circ}C$ to$37^{\circ}C$. However, the highest activity, along with the slow decrease of the enzymatic activity after reaching the maximum value, was observed at $25^{\circ}C$. By shifting the temperature from $37^{\circ}C$ to $25^{\circ}C$immediately after DO reached the minimum level, the high enzyme production of 1,100 U/ml along with the short fermentation period of 13 h could be obtained.

• 전자공학회논문지
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• 제52권9호
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• pp.141-146
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• 2015

최근 들어 건강에 대한 관심이 증가하면서 발효 식품에 대한 관심과 소비가 증가하고 있다. 대표적인 발효 식품으로 홍어가 있다. 홍어의 경우 각자의 취향에 따라 선호하는 정도가 매우 다르다. 그래서 홍어의 발효 정도를 수치화하여 보여줄 수 있다면, 사람들은 각자의 취향에 맞게 홍어를 먹을 수 있을 것이다. 본 논문에서는 스마트 RFID 태그를 이용하여 소비자의 취향에 맞는 홍어의 발효 정도를 모니터링 하는 시스템을 제안한다. 제안하는 시스템은 RFID 태그, $NH_3$센서, 리더기 및 서버로 구성되어 있다. 제안하는 시스템의 유용성을 확인하기 위해, 홍어 발효에 대한 실험을 한다. 제안한 모니터링 시스템은 홍어의 발효 정도를 Very Low, Low, Medium, Strong의 4등급으로 보여준다. 스마트 RFID 태그를 통해, 홍어의 발효 정도를 확실하게 추정한다.

• 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.

• 한국식품저장유통학회지
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• 제3권2호
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• pp.179-185
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• 1996

This study was carried out for the purpose of improving the persimmon vinegar. Crushed persimmon(persimmon pulp) was used at alcohol fermentation using Saccharomyces bayanus for persimmon alcohol medium preparation. Glucose(8.39%) and fructose(7.96%) were the dominant free sugar in persimmon pulp before the at cohol fermentation. They decreased abruptly during alcohol fermentation and glucose was consumed more rapidly than fructose. Final alcohol concentration was finally reached to 8%(v/v) in 5 days for mentation of persimmon pulp. Pectinase pre-treatment of persimmon pulp resulted in tusker contents of galacturonic acid, galactose, methyl alcohol and isoamyl alcohol in main mash for alcohol fermentation than those in main mash prepared without pectinase pre-treatment. After alcohol fermentation tannin concentration was 350ppm and astringency was not perceived.

• Asian-Australasian Journal of Animal Sciences
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• 제14권7호
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• pp.974-978
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• 2001

The effect of three varying ratios (high, medium and low) of Rumen Degradable Protein (RDP) to Undegradable Dietary Protein (UDP) of 37:63, 52:48 and 70:30 in iso-nitrogenous and iso-caloric concentrate mixtures on rumen fermentation profile was studied using rumen fistulated Jersey crossbred cows. Rumen pH and ammonia nitrogen concentration were found to be lower with a concentrate mixture containing a higher UDP level of 63.38% when compared with those having medium and low UDP levels of 47.55 and 29.75%, respectively, at all post feeding intervals. Total volatile fatty acid concentration as well as concentrations of individual fatty acids viz., acetate, propionate and butyrate were also found higher in animals fed concentrate mixture with the highest UDP level.

• Journal of Microbiology and Biotechnology
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• 제24권2호
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• pp.188-196
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• 2014

Extracellular production of recombinant human bone morphogenetic protein-7 (rhBMP-7) was carried out through the fermentation of Bacillus subtilis. Three significant fermentation conditions and medium components were selected and optimized to enhance the rhBMP-7 production by using the response surface methodology (RSM). The optimum values of the three variables for the maximum extracellular production of rhBMP-7 were found to be 2.93 g/l starch, 5.18 g/l lactose, and a fermentation time of 34.57 h. The statistical optimization model was validated with a few fermentations of B. subtilis in shake flasks under optimized and unoptimized conditions. A 3-L jar fermenter using the shake-flask optimized conditions resulted in a higher production (413 pg/ml of culture medium) of rhBMP-7 than in a shake flask (289.1 pg/ml), which could be attributed to the pH being controlled at 6.0 and constant agitation of 400 rpm with aeration of 1 vvm.