• Korean journal of food and cookery science
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• v.28 no.4
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• pp.391-397
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• 2012

This study was carried out to investigate commercialization of Kimchi made of cabbage (Brassica oleracea var. capitata L.) using pre-fermentation conditions. The pre-fermentation conditions were 0, 18, 24, and 28 h at $20^{\circ}C$, and then the samples were stored at $10^{\circ}C$ to assess changes in quality characteristics. A comparison of the quality characteristics during storage showed that PF24 (pre-fermented cabbage Kimchi during 24 h at $20^{\circ}C$) and PF28 (pre-fermented cabbage Kimchi during 28 h at $20^{\circ}C$) had pH 4.47 and pH 4.23 on the second day of storage, respectively. It was possible to shorten the fermentation time to less than that of PF0 (not pre-fermented cabbage Kimchi at $20^{\circ}C$), by approximately 3 days. Total acidity was 0.26 to 0.29% immediately after making the Kimchi. However, PF0, PF18 (pre-fermented cabbage Kimchi during 18 h at $20^{\circ}C$), PF24 and PF28 became well-fermented when they were stored for 8~14 days, 3~10 days or 2~3 days. The number of lactic acid bacteria increased with the passage of time in all treatment groups regardless of fermentation conditions. However, the longer pre-fermentation time became, the faster the number of lactic acid bacteria increased. Most samples showed similar results late in the storage period; 7.2~7.4 log CFU/mL. PF0 had the greatest volume change 2.1 times increase late in the storage period. The sensory evaluation showed significant differences for flavor, taste, and overall acceptability after a partial storage period. PF28 stored for 2~3 days showed excellent flavor, and PF24 and PF28 stored for 2~3 days showed the highest scores of 6.27 to 6.67. The PF24 and PF28 treated samples were appropriate for commercializing small packed cabbage Kimchi and for alleviating the expansion problem of the packing material. However, because mass commercial production requires a large number of samples to be used at once, the results should be assessed for industrial product development in the future.

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.217-222
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• 1982

A lactic starter organism, Lactobaciilus casei YIT 9018 was treated with N-methyl-N'-nitro-N-nitrosoguanidine (NTG) to obtain phage-resistant mutants. Freshly grown cells suspended in citrate buffer were exposed to NTG of 50 g/$m\ell$ for 40 min. Among 88 colonies isolated eight colonies showed distinct resistance to phages isolated previously from milk plants. The eight new colonies showed character similar to the original L. casei except that they responded differently to phage of different sources and thus were designated as eight different mutants of L casei. From the phage resisting toaether with the fermentative ability equivalent to the mother organism the mutants may be considered to be used as starter cultures for fermented milk.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.398-404
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• 1991

- Ethanol production by calcium alginate-immobilized baker's yeast was studied in the continuous shaked-flask reactor (CSFR) using glucose medium as a feed. Immobilized cells were stable at 30~$37^{\circ}C$ and pH 4~8. Fermentation characteristics of immobilized baker's yeast were examined changing the initial glucose concentration employed were 50, 100 and 150 g/l, respectively. It was investigated that the influent glucose concentration and the dilution rate have an influence on the ethanol fermentation characteristics at steady state in continuous culture of immobilized baker's yeast. The optimum conditions for high ethanol productivity and low residual glucose output in ethanol prodution were shown to be 0.2 h ' for the dilution rate and 150 g/l for the influent glucose concentration. The maximum ethanol productivity, ethanol yield, specific growth rate and glucose conversion rate were around 7.12 g/$l\cdot h$, 0.23, 0.366 g/$l\cdot h$ and 78.43, respectively.

• KSBB Journal
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• v.23 no.1
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• pp.54-58
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• 2008

Hydrogen is considered as an energy source for the future due to its environmentally friendly use in fuel cells. A promising way is the biological production of hydrogen by fermentation. In this study, the optimization of medium conditions which maximize hydrogen production from Enterobacter aerogenes KCCM 40146 were determined. As a result, the maximum attainable cumulative volume of hydrogen was 431 $m{\ell}$ under the conditions of 0.5M potassium phosphate buffer, pH 6.5 medium containing 30 g/L glucose. The best nitrogen sources were peptone and tryptone for the cell growth as well as hydrogen production. The control of cell growth rate was found to be a important experimental parameter for effective hydrogen production

• KSBB Journal
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• v.18 no.5
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• pp.418-423
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• 2003

A laboratory jar fermenter was modified to measure the duration for cooling water supply and the temperatures of the coolant at the inlet and outlet of water jacket. Successful operation of temperature control and on-line measurement was achieved by adjusting optimum parameters of the Proportion-Integral-Derivative temperature controller. The variables measured on-line were used to estimate cooling rates from empirical equations comprised of the time period of cooling water supply and the temperatures of coolant. The measured cooling rate showed a good correlation to the specific growth rate during batch cultivation of E. coli. Cooling rate was measured and applied to programmed cell growth in a fed-batch cultivations. Three fed-batch cultivations were demonstrated by feeding substrate to follow the programmed cooling rates increasing exponentially.

• Korean Journal of Microbiology
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• v.28 no.4
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• pp.345-350
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• 1990

In order to ferment D-xylose directly to ethanol, Yeasts capable of utilizing D-xylose as a sole carbon source and energy source were isolated from soil, sawdust and rotten woods. Among them, the yeast strain, which showed the best ability to produce ethanol, was identified as Candida sp. L-16 isolated from rotten woods. The optimal conditions for production of ethanol were 60rpm of agitation speed, 28j.deg.C of temperature, 4.5 of initial pH and 5% of D-xylose concentration. Ethanol production was reached to maximum state for 4 days culture. Under these optimal conditions, the maximum ethanol concentration and theoretical ethanol yield were 2.4%(v/v) and 74.4% of theoretical value, respectively.

• Journal of Life Science
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• v.6 no.1
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• pp.6-13
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• 1996

The possible use of milk-wastewater as a fermentation media for the production of citric acid by Aspergillus niger has been investigated. The addition of Mn$^{2+}$ , Fe$^{2+}$ and Cu$^{2+}$ to the medium promoted citric acid production while only Mg$^{2+}$ decreased citric acid production. The concentrations of citric acid produced were marked up to 7.2g/l and 16.5g/l in a batch bioreactor by Aspergillus niger ATCC 9142 with 50g/l and 100g/l of reducing sugar concentration in milk-wastewater, respectively. A mathematical model was developed and simulating the predictability of cell growth, citric acid production and substrate consumption rate, and gave good agreement results with experimental data.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.201.2-202
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• 2003

생체조직에 있어서 환원형 Glutathione(${\gamma}$-L-glutamyl-cysteinyl-glycine, GSH)은 항산화 작용, 간기능 회복 및 해독작용등의 생체 내에서 중요한 생리활성기능을 가지고 있다. 본 연구에서는 glutathione을 다량으로 함유하는 효모균주를 전통 발효주로부터 분리하여 최적 생산을 검토하였다. 분리된 균주는 형태학적, 생리학적 및 생화학적 특성을 검토한 결과 Saccharomyces cerevisiae로 동정되어 FF-8로 명명하였다. Glutathione 생산을 위한 Saccharomyces cerevisiae FF-8의 최적 생산조건은 YM(glucose 1.0%, acid peptone 0.5%, yeast extract 0.3%, malt extract 0.3%) 배지를 기본으로 하여 72시간 동안 진탕배양하면서 검토하였다. Glutathione 생산을 위한 최적 온도, 교반속도 및 pH는 각각 3$0^{\circ}C$, 100 rpm, 그리고 pH 6.0으로 나타났다. Glutathione 최대 생산배지조건은 탄소원으로 3%의 glucose, 질소원으로 3%의 yeast extract, 무기질원으로 0.06%의 KH$_2$PO$_4$및 전구체로 0.06%의 L-Cysteine으로 하였을 때 최대 생산량을 나타내었고, 최적 배지상에서 204$\mu\textrm{g}$/$m\ell$을 생산하였다.

• Journal of Dairy Science and Biotechnology
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• v.35 no.1
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• pp.33-38
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• 2017

This study was conducted to investigate the fermentation forms of goat milk, and the changes in the flavor of goat milk fermented using single and mixed strains of commercial Lactobacilli during storage. The mixed strains reached a lower pH more quickly than the single strains. The mixed strains also had higher rates of Lactobacillus proliferation. The tastes detected in sensory tests can differ depending on the skill levels of the panel, making it difficult to obtain reproducible and objective data when numerous samples are analyzed. Therefore, we measured changes in flavor during storage using taste sensors. The taste sensors measured diverse flavor changes in goat milk fermented using single strains and mixed strains. Notably, this study is the first in our country to measure changes in the taste and composition of fermented milk during cold storage using taste sensors. This work could have great value for the maintenance and monitoring of dairy products within their expiration dates.

• Microbiology and Biotechnology Letters
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• v.17 no.2
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• pp.165-169
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• 1989

To achieve higher ethanol productivity in the fermentation system, a continuous ethanol production has been investigated with the air-supplement in a packed-bed immobilized cell reactor system. Yeast cells were immobilized using sodium alginate gel. The results showed that, when the feed medium was saturated with oxygen through aeration into the medium reservoir, the maximum ethanol productivity of the reactor was enhanced from 35 g/$\ell$-gel-hr to 55 g/$\ell$-gel-hr at the residence time of 10-20 min. and the residence time for the 90% conversion of substrate to ethanol was reduced from 40 min. to 25 min. In case of 18% glucose medium, the maximum productivity was increased from 35 g/$\ell$-gel-hr to 45 g/$\ell$-gel-hr and time required for 90% conversion was from 90 min to 70 min. This behavior of air-supplemented reactor system might be due to the fact that both growth and viable fraction of yeast within the Eel were increased during reactor operation.