• KSBB Journal
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• v.6 no.4
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• pp.379-383
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• 1991

Pervaporation can be successfully utilized to recover alcohol from fermentation broths and dilute process streams. Polydimethylsiloxane (thickness: $60\mu$m), such as hydrophobic membrane have been employed in this application to produce an enriched product. The fermented alcohol was continuously extracted, and simultaneously concentrated by pervaporation, from the membrane bioreactor, and the extracted alcohol concentration was 6 to 10 times higher than in the broth. This experimental conditions were 6-10 Torr vacuum line, pH=5, $32^{\circ}C$, 3.5 liters of working volume, 200rpm of agitator speed, and 0.14 wm aeration flow rate.

• KSBB Journal
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• v.16 no.5
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• pp.516-522
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• 2001

The large-scale production of antibiotics by filamentous mycelial organism requires and adequate supply of dissolved oxygen. In terms of productivity, it means that oxygen transfer is the rate-limiting step. Therefore, the oxygen transfer coefficients(K$\_$L/A) were determined in a broth involving a filamentous mycelial organism such as Streptomyces avermitilis for use in fermentations. To determine (K$\_$L/A) inn a stirred vessel, a great deal of effort is required to provide all the cells with a sufficient oxygen supply. To overcome the oxygen limitation in a batch culture, a fed-batch culture was applied to control the growth rate by an intermittent supply of nutrients. Thus, it was possible to maintain a suitable dissolved oxygen concentration at a low agitation rate. The optimal agitation speed was 350 rpm at low cell concentrations (below 7 g/L) by considering the efficiency of agitation and shear stress. The (K$\_$L/A) was found to decrease from 64.26 to 29.21h.$\^$-1/ when the biomass concentration was increased from 9.82 to 12.06 g/L. In addition, and increase in viscosity was also observed during the growth phase. By comparing the (K$\_$L/A) values for the various agitation and aeration rates, it was found that the effect of an increase in (K$\_$L/A) by aeration was reduced dramatically at high biomass concentrations. However, this effect was not observed when altering the agitation rate. This suggests that controlling the dissolved oxygen concentration by altering the agitation rate was more efficient than increase the aeration rate.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.312-312
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• 2017

The study was conducted to select optimal materials for promoting germination rate, high sprouting vigor by priming treatment using PEG 6000 (water potential -0.5 to 2.0 Mpa) and Azolla extracts (0.1, 1.0, and 10.0%) extracted by ethanol, distilled, and/or hot water in colored rice cultivars. Each rice seed (three black rice cultivars and two red rice cultivars) was soaked 24 and 48 hr including untreated control. In black rice, Joseongheugchal rice cultivar, azolla ethanol extract (0.1%) induced highest germination rate, germination speed was taken to 5 days in distilled water and to 3days in Azolla extracts extracted hot water. Otherwise, degree of bacterial inhibition (number of colony, $10^3cfu$) in dry seed, water soaking for 24hr, soaking with fungicide for 24hr and 48hr, soaking with fungicide and aeration for 24hr and 48 hr was 22, 500, 95, and 0.46, respectively. In order to minimize fungal inhibition, a method can be chosen to combination of soaking fungicide and aeration for 48 hr. In seed priming treatments using growth pouch, seed soaking with fungicide did not affect change of germination percentage and germination speed, it delayed only 2 or 4day in the Joseongheugchal rice cultivar. It differs from rice cultivars and priming materials, Azolla extract(0.1 to 1%) promotes seed germination percentage in the Ilpum, Hongjinju, and Joseonghuegchal, in addition, germination in Jeogjinju cultivar was only promoted by PEG solution(10 to 20%), otherwise, it showed much lower or inhibited on the germination in Heugjinju and Sinmyungheugchal rice cultivars. In a paddy field trial, seedling establishment rate by applying PEG6000 and azolla extract did not show significantly statistical difference. When it compared with untreated control, seedling establishment rate was increased over 50% in priming treatments. Interestingly, seedling establishment rate under azolla extract (0.1%) extracted with ethanol was promoted over 2.5 times compared to the control in a black rice, Joseongheugchal and red rice, Jeogjinju.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.263-266
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• 2000

The purified biosurfactant $3.16g/{\ell}$ was obtained after cultivation for 104hr at $25^{\circ}C$ with an optimal agitation speed of 200rpm, an aeration rate of 2vvm in a $14{\ell}$ fermenter containing $5.5{\ell}$ of LB medium and 1%(w/v) olive oil as a carbon source. For the kinetic studies, the optimal substrate concentration was analyzed on different olive oil concentrations(0.1, 0.5, 1.0, 1.5, 2.0%(w/v)) and optimal culture conditions(MLBM, 200rpm, 2vvm at $25^{\circ}C$) in a $14{\ell}$ jar fermenter. The results obtained indicate that $K_s$=0.0086 $g/{\ell}$, $q_s$= 0.664 $g/g{\cdot}h$, $q_p$= $4.2{\times}10^{-3}$ $g/g{\cdot}h$, and ${\mu}_{max}$ was determined as $0.1449h^{-1}$.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.187-191
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• 2005

The Study was carried out to investigate in the optimal mycelial growth and Exo-Polysaccharides of Fomitopsis pinicola. Jar fermentations were carried out to optimize the culture conditions for mycelial growth and exo- polysaccharide production. The optimal agitation speed and aeration rate were 200 rpm and 1.5 v.v.m., respectively. Under optimal culture conditions, the maximum mycelial growth and exo-polysaccharide production after 11 days with a 5 L jar fermenter containing the optimized medium were 10.21 g/L and 3.56 g/L, respectively. However, the fundamental information obtained this study is insufficient in the development of a efficient process for mycelial growth and exe-polysaccharide production from Fomitopsis pinicola.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1993.04a
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• pp.39-53
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• 1993

The minimum oil film thickness(MOFT) in the connecting-rod bering of a 1.5 liter, L-4, gasoline engine is measured up to 5500 rpm and calculated to study the dynamically loaded engine bearing. Short bearing approximation and Mobility method are used for theoretical analysis of oil film charactrtistics. And cylinder pressure, crank-pin surface temperature and bearing tenp ture are measured as the input data of theoretical analysis. The MOFT are measured by the total capacitance method(TCM). To improve the reliability of the test results, a reasonable detmuuination method of bearing clearance is introduced and used, and the effects of cavitation and aeration on the test results are neglected. The crankshaft is grounded by means of a slip ring. A scissor type linkage system was developed to measure the MOFT and bearing temperature. The effects of engine speed, load and oil viscosity on the measured and calculated minimum oil film thicknesses are investigated at 1500 to 5500 rpm. From the comparison between the measured and calculated MOFT, it is found that a qualitative similarity exists between them, but in all cases, the measured MOFT are smaller than those calculated.

• Microbiology and Biotechnology Letters
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• v.28 no.6
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• pp.349-354
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• 2000

Culture conditions and nitrogen sources were optimized for production of erythritol, a natural sweetener, by Candida magnoliae M26. The optimal culture conditions were found to be culture temperature of $28^{\circ}C$, initial pH of 7, aeration of 1 vvm and agitation speed of 500 rpm in a 2.5 1 jar-fermentor. Glucose was chosen as the best carbon cource bsed on cell growth and erythritol productivity. Kight steep water(LSW) and corn steep liquor (CSL) which are by-products in starch processing from corn were tested as a nitrogen source substitute for yeast extract. The use of either LSW or CSL did not change the fermentation performance. The experimental results using LSW and CSL showed 1.5 times higher in cell growth and almost the same value in erythritol productivity com-pared with the control fermentation using yeast extract as a nitrogen source. These results suggested that either LSW of CSL could be used as a nitrogen source in a large-scale fermentation for erythritol production.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1603-1611
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• 2009

High-cell-density cultivation of yeast was investigated using the agricultural waste products corn steep liquor (CSL) and molasses. The Saccharomyces cerevisiae KV-25 cell mass was significantly dependent on the ratio between C and N sources. The concentrations of molasses and CSL in the culture medium were statistically optimized at 10.25% (v/v) and 16.87% (v/v), respectively, by response surface methodology (RSM). Batch culture in a 5-l stirred tank reactor using the optimized medium resulted in a cell mass production of 36.5 g/l. In the fed-batch culture, the feed phase was preceded by a batch phase using the optimized medium, and a very high dried-cell-mass yield of 187.63 g/l was successfully attained by feeding a mixture of 20% (v/v) molasses and 80% (v/v) CSL at a rate of 22 ml/h. In this system, the production of cell mass depended mainly on the agitation speed, the composition of the feed medium, and the glucose level in the medium, but only slightly on the aeration rate.

• Journal of Life Science
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• v.12 no.5
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• pp.570-576
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• 2002

The extremely halophilic archaebacterium Haloarcular sp. EH-1 was isolated from solar salts. Amylae production from Halonrcular sp. EH-1 have been studied. The results obtained were as follows. The optimal medium composition for the production of amylase from Haloarcular sp. EH-1 were soluble starch 1.5%, yeast extract 1.0%, MgSO$_4$ 7h$_2$O 2.0%, KCI 0.1%, NaCl 25% (pH 7.5). The incubation temperature, aeration rate and agitation speed were 4$0^{\circ}C$, 100 $m\ell$ medium / 500 $m\ell$ shaking flask, and 110 rpm. The cell growth and enzymatic activity was highest at 9 days of incubation. So amylase production appeared to be a growth-related phenomenon.

• Journal of environmental and Sanitary engineering
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• v.24 no.1
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• pp.40-46
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• 2009

The enzyme expressed from strain L-49 was 2.01 times higher than that of original strain. Strain L-49 can grow on culture plate with $50{\mu}g/mL$ ampicillin. The synthesis of $\alpha$-amylase was greatly suppressed when strain L-49 was grown on monosaccharide such as glucose and polysaccharide at the same time cell concentration was low. Amylase production was enhanced when the bacterium was grown on starch and dextrin. Among different nitrogen sources tried, yeast extract was found to be the best followed by panpeptone, peptone, meat extract, bean meal, and corn steep liquor. The average rate of enzyme production was enhanced for 3~4 times in fermentation time from 24h to 44h. The sugar uptake rate has also increased. Low oxygen supply rate enhanced the rate of strain propagation but depressed the enzyme production. Hence it is benefit to obtain high enzyme activity that agitation speed maintained not lower than 400r/min and aeration rate maintained greater than 1:1vvm.