• Journal of Microbiology and Biotechnology
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• 제28권5호
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• pp.697-706
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• 2018

Lactobacillus pentosus K1-23 was selected from among 25 lactic acid bacterial strains owing to its high inhibitory activity against several pathogenic bacteria, including Escherichia coli, Salmonella typhimurium, S. gallinarum, Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium perfringens, and Listeria monocytogenes. Additionally, among 13 strains of Aureobasidium spp., A. pullulans NRRL 58012 was shown to produce the highest amount of ${\beta}$-glucan ($15.45{\pm}0.07%$) and was selected. Next, the optimal conditions for a solid-phase mixed culture with these two different microorganisms (one bacterium and one yeast) were determined. The optimal inoculum sizes for L. pentosus and A. pullulans were 1% and 5%, respectively. The appropriate inoculation time for L. pentosus K1-23 was 3 days after the inoculation of A. pullulans to initiate fermentation. The addition of 0.5% corn steep powder and 0.1% $FeSO_4$ to the basal medium resulted in the increased production of lactic acid bacterial cells and ${\beta}$-glucan. The following optimal conditions for solid-phase mixed culture were also statistically determined by using the response surface method: $37.84^{\circ}C$, pH 5.25, moisture content of 60.82%, and culture time of 6.08 days for L. pentosus; and $24.11^{\circ}C$, pH 5.65, moisture content of 60.08%, and culture time of 5.71 days for A. pullulans. Using the predicted optimal conditions, the experimental production values of L. pentosus cells and ${\beta}$-glucan were $3.15{\pm}0.10{\times}10^8CFU/g$ and $13.41{\pm}0.04%$, respectively. This mixed culture may function as a highly efficient antibiotic substitute based on the combined action of its anti-pathogenic bacterial and immune-enhancing activities.

• International Journal of Advanced Culture Technology
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• 제1권2호
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• pp.18-23
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• 2013

In this paper, we consider the problem of designing optimal sensing time and the minimization of energy consumption in the Cognitive radio Network. Trade-off between throughput and the sensing time are observed, and the equations are derived for the optimal choice of design variables. In this paper, we also look at the optimization problem involving all the design parameters together. The advantages of the proposed scheme for the spectrum sensing and access process are shown through simulation.

• Mycobiology
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• 제37권3호
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• pp.218-224
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• 2009

The principal objective of this study was to determine the optimal liquid culture conditions in shake flasks for maximal sporulation of Beauveria bassiana. The optimal initial pH for the spore production of B. bassiana using Potato Dextrose Broth was 5.2. The screening in shake flasks of carbon and nitrogen sources resulted in the identification of an optimal medium based on 3% sucrose and 1% casamino acid, with a C : N ratio of 22 : 4. Using this medium, a production level of $5.65{\times}10^7$ spores per ml was obtained after 5 days of culture. Using 3% corn meal, 2% corn steep powder, and 2% rice bran, the maximum spore concentration of $8.54{\times}10^8$/ml was achieved 8 days after inoculation at $25^{\circ}C$ in a rotary shaking incubator operated at 200 rpm. This represents a yield gain of approximately 2.89 times that of pre-optimization.

• Asian-Australasian Journal of Animal Sciences
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• 제21권4호
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• pp.532-537
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• 2008

In order to investigate the factors affecting the culture of mouse preantral follicles in vitro, we examined the effect of culture media, protein supplements, and culture period on their growth. The oocyte diameter (initial size: $55.6{\pm}2.5{\mu}m$) was progressively increased during culture, and the maximum size ($72.0{\pm}2.4{\mu}m$) was reached on day 10 of the in vitro culture. The chromatin configuration in the germinal vesicle (GV) oocyte progressively shifted from a non-surrounded nucleolus (NSN) to a surrounded nucleolus (SN). On day 10 of the culture, most of the oocytes progressed to the SN pattern. The survival and metaphase II rates of the oocytes in alpha-minimal essential medium (alpha-MEM) were significantly higher (p<0.05) than those in Waymouth and tissue culture medium (TCM)-199. As a protein source, fetal bovine serum (FBS) was more suitable for the culture of mouse preantral follicles as compared to human follicular fluid (hFF) and bovine serum albumin (BSA); the optimal concentration of FBS was 5%. These results suggest that in a culture of mouse preantral follicles, alpha-MEM and 5% FBS are an optimal medium and a protein source, respectively; further, the 10 days of culture is required for the complete growth of oocytes in this culture system.

• 한국수정란이식학회지
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• 제25권4호
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• pp.251-258
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• 2010

In the present study, effects of concentration and time of culture in presence of roscovitine on nuclear maturation and meiotic spindle configuration, chromosomal alignment were examined in porcine oocytes. In experiment 1, porcine cumulus oocyte complexes (COCs) were cultured at $39^{\circ}C$ in a 5% $CO_2$ atmosphere in North Carolina State University 23 (NCSU-23) supplemented with 25, 50, 75 or $100\;{\mu}M$ roscovitine for 22 h and then were cultured for additional 22 h after removal of roscovitine. Nuclear maturation and morphology of the meiotic spindle and chromosomal alignment were examined to determine the optimal concentration of roscovitine in oocyte maturation. In experiment 2, COCs were cultured in NCSU-23 supplemented with $50\;{\mu}M$ roscovitine for 17, 20, 27 or 42 h and then an additional 22 h without roscovitine was followed to determine the optimal time of culture. The optimal concentration of roscovitine to arrest and resume meiosis of porcine oocyte was $50\;{\mu}M$ by examining nuclear status (p<0.05) and normal spindle and chromosome configuration. The optimal time of culture in presence of roscovitine to arrest meiosis of porcine oocyte was 17 h (p<0.05), although MII rates and normal morphology of the meiotic spindle and chromosomal alignment were not significantly different among various times of culture. In conclusion, the optimal concentration and time of culture in presence of roscovitine to arrest porcine oocytes are $50\;{\mu}M$ and 17 h, respectively.

• 한국식품저장유통학회지
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• 제10권4호
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• pp.554-559
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• 2003

동치미로부터 분리된 Latobacillus sp. FF-3의 Bacteriocin 생산에 대한 최적 배양조건과 배양 특성을 조사하였다. Bacteriocin 생산을 위한 최적 생산조건은 MRS(proteose peptone 1%, beef extract 1%, yeast extract 0.5%, glucose 2%, polysorbate 80 0.1%, ammonium citrate 0.2%, sodium acetate 0.5%, magnesium sulfate 0.01%, manganese sulfate 0.005%, dipotassium phosphate 0.2%) 배지를 기본으로 하여 21시간 배양한 결과, 배양온도는 30∼37$^{\circ}C$, 초기 pH는 7.0 으로 확인되었다. 최적 생산배지조성으로 탄소원은 glucose 3%, 질소원은 tryptone 4%, 무기염류는 manganese sulfate 0.005%가 bacteriocin 생성에 최적 조성으로 나타났으며, 최적 배지상에서 항균활성은 최대 484 BUf/mL로 나타났다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.355-358
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• 2001

팽나무버섯균의 배양환경조사에서 최적배양온도는 $20^{\circ}C$, pH는 $6.0{\sim}7.5$ 탄소원은 yellow sugar. potato starch. 질소원은 soybean flour. Yeast extract. 무기염류는 $KH_2PO_4,\;MgSO_4,\;7H_2O$를 0.05%(w/v)에서 우수한 생장을 나타냈다. 액체종균 배양 실험에서는 전 배양시 erlenmeyer flask에서 6 일간 $21^{\circ}C$, 125rpm으로 배양 후 본 배양시 5% 접종량, 1.0vvm 통기로 4-5 일 배양하였을 때 균체량이 높게 나타났다.

• 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.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.69-74
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• 2000

The medium for erythritol production by Torula sp. in a 500-ml baffled flask was optimized to be 300 g/I sucrose, 10 g/I yeast extract, 3 g/I $KH_2PO_4$, and 10 mg/I $CuSO_4{\cdot}5H_2O{\;}at{\;}34^{\circ}C$ with initial pH of 5.5. Using this optimal medium, erythritol of 166 g/I was obtained after 140 h of cultivation, corresponding to 55.3% of the erythritol yield from sucrose with a productivity of 1.11 g/I/h. Optimal concentrations of carbbon and nitrogen sources in a fermentor were higher than that in a flask due to the higher oxygen supply of the fermentor. Employing the medium containing 300 g/I or 400 g/I sucrose for the determination of optimal C/N ratio, the C/N ratio was found to be more important than the nitrogen concentration for effective erythritol production, The optimal ratio of yeast extract to sucrose (g/g) was 20. The yield and productivity of erythritol were maximal in the medium containing 400 g/I sucrose and 20 g/I yeast extract. when dissolved oxygen in the culture was increased, the cell mass increased but the erythritol production was manimal in the range of 5 to 10% of dissolved oxygen. Under the optimal the rane of 5 to 10% of dissolved oxygen. Under the optimal culture condition of the fermentor, a final erythritol concentration of 200 gI was obtained after 120 h with a yield of 50% and the productivity was 1.67 g/I/h. The yield was the highest among erythritol-producting microorganisms

• Journal of Microbiology and Biotechnology
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• 제23권4호
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• pp.539-544
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• 2013

The effects of culture depth (2-10 cm) and cell density on the growth rate and biomass productivity of Chlorella sp. XQ-200419 were investigated through the use of a self-designed open circular pond photobioreactor-imitation system. With increases in culture depths from 2 to 10 cm, the growth rate decreased significantly from 1.08 /d to 0.39 /d. However, the biomass productivity only increased slightly from 8.41 to 11.22 $g/m^2/d$. The biomass productivity (11.08 $g/m^2/d$) achieved in 4 cm culture with an initial $OD_{540}$ of 0.95 was similar to that achieved in 10 cm culture with an initial $OD_{540}$ of 0.5. In addition, the duration of maximal areal productivity at a 4 cm depth was prolonged from 1 to 4 days, a finding that was also similar to that of the culture at a 10 cm depth. In both cases, the initial areal biomass densities were identical. Based on these results and previous studies, it can be concluded that the influence of culture depth and cell density on areal biomass productivity is actually due to different areal biomass densities. Under suitable conditions, there are a range of optimal biomass densities, and areal biomass productivity reaches its maximum when the biomass density is within these optimal ranges. Otherwise, biomass productivity will decrease. Therefore, a key factor for high biomass productivity is to maintain an optimal biomass density.