• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.303-311
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• 1996

The microflora changes of 10 water-controled treatments combined with livestock manures(pig, chicken) and bulking agents(sawdust, paper sludge) were investigated. The B/F values of the P-1 and C-1(65%, $H_2O$) treatments were 3571 and 5400 respectively, but those of the P-4 and C-4(50%, $H_2O$) treatments showed very low values, 667 and 334, respectively. The B/F values tended to increase with higher water content of the treatments. In the composting processes, the successions of microflora, adapting the compost environments, took place via fluctuating temperature. In the high temperature period, the numbers of mesophilic bacteria and fungi decreased, but that of the spore forming bacteria increased. However, the number of mesophilic bacteria inereased during the cold period. The B/F values of compost ranged 25-300, which indicates a decrease in the quantity of bacteria. The time required for the temperature of compost to reach $60^{\circ}C$ showed different patterns. There was no pathogenic microorganism in the treatments which reached a high temperature in a short period of time, but, in the treatments which reached a high temperature over a Long period of time, the pathgenic microorganism was not still alive.

• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.46-50
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• 2003

Lactococcus lactis SA72 from Jeot-gal (Korean traditional fermented fish foods) produces lacticin SA72. The influence of several parameters on the fermentative production of lacticin SA72 by Lactococcus lactis SA72 was studied. MRS medium among several media was selected for enhanced bacteriocin production. The mean growth rate and bacteriocin productivity of L. lactis SA72 increased as the initial pH of the media increases. The highest lacticin SA72 activity was detected 3,200 AU/ml at pH 6.0, $32^{\circ}C$, and 1% (inoculum size, v/v) in the jar fermenter. Enhanced production of lacticin SA72 was investigated by a fed-batch cultivation with the intermittent feeding of the concentrated glucose solution. Under the optimized conditions, lacticin SA72 activity finally reached to 6,400 AU/ml.

• Journal of Ginseng Research
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• v.33 no.2
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• pp.143-148
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• 2009

This study was carried out to detennine the optimal submerged culture conditions for the growth increase of ginseng adventitious roots containing germanium by means of a fractional factorial design with four factors and three levels, using the response surface methodology (RSM). The ginseng (Panax ginseng CA. Meyer) adventitious roots were induced by plant growth regulators and cultured in a liquid SH medium. The effects of various $GeO_2$ and phosphoric acid ($H_3P0_4$) concentrations in the medium, $GeO_2$ addition time and the pH of the medium on the fresh weight of the ginseng adventitious roots were investigated. The optimum pH of the medium and the phosphoric acid concentration detennined by the partial differentiation of the model equation were 4.7 and 6.0 roM, respectively. The predicted optimal $GeO_2$ concentration was 10 ppm and the $GeO_2$ addition time did not affect the growth of ginseng adventitious roots. Under these conditions, the growth of the ginseng adventitious root containing germanium was predicted to be 2.47 g.

• Microbiology and Biotechnology Letters
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• v.15 no.6
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• pp.396-401
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• 1987

Protein productivities of a cloned gene ($\beta$-galactosidase) and the cultural performances of two recombinant Escherichia coli strains, which use different host-vector systems, were studied. E. coli JM109/pTBG10 strain which carries Tac promoter had higher protein productivity than E. coli MH3000 (pRKc1857)/pASI(lacZ) strain which carries pL promoter. Induction of protein syn-thesis was optimum at the initial-and mid-logarithmic growth phases for both strains. Oxygen demand was observed to be very high during the cloned gene expression, and could be alleviated to some extent through pH control. The ratio of specific growth rates of plasmid-harboring to plasmidfree cell, $\mu$+ /$\mu$-, of the high productivity strain was observed to be lower than that of the low productivity one. Plasmid stability was analyzed for 20-30 generations, and it was found that the traction of plasmid-harboring cells dropped to l0% level in about 25 generations for both strains when the cloned gene expression was induced.

• KSBB Journal
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• v.8 no.4
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• pp.382-389
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• 1993

In order to elucidate the effect of acetate ion on the growth of Escherichia coli, flask and fermentor cultures were performed using M9 and LB media. Acetic acid was secreted at a higher rate under the conditions of high glucose concentration as well as of richer medium, i. e., LB broth. The pH in flask culture could not be controlled as i fermentor and pH decreased with the formation of acetic acid. The inhibition effect of acetic acid was pronounced at a lower pH, and the effective inhibitory concentrations of acetic acid were 2.0g/l for LB flask culture, 4.0g/l for M9 flask culture, and 8.0g/l for M9 fermentor culture. Dialysis flask culture was designed to slowly provide E coli cells with glucose. Solid LB agar was layered under LB liquid medium with the variation of agar concentration and solid volume, The increase in the solid portion in the total volume(agar＋liquid) resulted in the increase of the final cell concentration. This can be ascribed to the fact that the larger solid phase behaves like a larger reservoir for glucose and controls the growth of E. coli with a controlled rate.

• KSBB Journal
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• v.18 no.4
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• pp.312-317
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• 2003

The addition of glycine up to 0.5％ (w/v) to Luria broth (LB) media on the secretion of levansucrase in a recombinant strain Escherichia coli JM109/pUPLK1 was observed to enhance the release of periplasmic proteins from the cell to the broth, without significantly affecting the cell growth rate and protein productivity. However, the glycine concentration at 1 ％ (w/v), the cell density attainable at the stationary phase fell to about 50％ and the extracellular activity of levansucrase corresponded to about 80％ of the total (extracellular plus intracellular) activity and increased by 2.6-fold, comparing to the cells grown in the absence of glycine. The increased pH at stationary phase accelerated the degradation of levansucrase. Maximal extracellular activity was attained when 1 ％ glycine was supplemented at the onset of strain growth.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.18-23
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• 2005

The purpose of this work was to investigate the physiological characteristics of Lactobacillus sp. JK-8 isolated from a shrimp aquaculture pond. The strain JK-8 was grown on MRS media, and morphological and physiological characteristics of the strain were examined. The bacterium was identified as a strain of the genus Lactobacillus on the basis of BIOLOG test. Strain JK-8 produced both lactic acid and acetic acid, which were responsible for the pH decrease during growth. Concentrations of lactic acid and acetic acid increased to 192.8 mM and 43.6 mM, respectively, and the initial pH 7.0 of the cultures decreased to 3.8 at the end of incubaction. The bacteriocidal effect against eight target bacteria was examined with 5-fold concentrated culture supernatants. All bacteria tested in this work were completely killed within 3 hrs after treatment with the culture supernatant. The bacteriocidal effects were clearly observed, only when the pH of the culture supernatants were not adjusted. HPLC was used to reslove lactic acid and acetic acid in the culture solution, and GC-MS was used to verify the metabolites.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.61-66
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• 2004

To investigate the effect of charcoal on the physico-chemical characteristics in the growing media and the growth of oriental melon, six treatment, 0%, 10%, 20%, 30%, 40%, and 50% charcoal, were added into the growing media, Baroker. The value of pH in the charcoal contained growing media (CGM) was recorded higher and further increased by raising the charcoal ratio and by growing period. In 20% CGM, the range of pH was adequate to grow crop as 5.2${\sim}$5.8. Contents of Ca and K in CGM increased by raising the ratio of charcoal, while contents of Mg and Na decreased. The growth of oriental melon seedlings in 20% and 30% CGM was better than in other treatments, in terms of fresh and dry weight of shoot, plant height, leaf area, lear width and relative growth rate. Both the physico-chemical properties of growing media and the growth of oriental melon seedlings were changed by the addition of charcoal. These results suggest that charcoal can be used as mixing material with other potting media for producing the seedling of good quality.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.768-774
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• 2009

To improve the productivity of 1,3-propanediol(1,3-PD) with K. pneumoniae DSM4799 using pure glycerol and crude glycerol derived from the biodiesel process, optimizing fermentation conditions was performed by changing environmental factors such as anaerobic/aerobic condition, temperature, glycerol concentration, and pH. When anaerobic conditions were maintained, there was an improved 1,3-PD production compared with that from aerobic/anaerobic 2-stage fermentation. From the results with temperature $26{\sim}37^{\circ}C$, the higher 1,3-PD production yield was observed at $30{\sim}33^{\circ}C$. For an initial glycerol concentration higher than 60 g/L, cell growth and 1,3-PD production were inhibited. When crude glycerol was used, the initial 1,3-PD production appeared to be inhibited. After 48 hr of incubation, however, 1,3-PD production with crude glycerol was even higher than that with pure glycerol, demonstrating the feasibility of 1,3-PD production using crude glycerol as a substrate. Fed-batch fermentation was applied for the high concentration of 1,3-PD without substrate inhibition. By regulating pH at 7 during the fed-batch with glycerol lower than 40 g/L, the yield of 1,3-PD was 25% higher than that without pH regulation(0.56 g/g vs. 0.45 g/g). In conclusion, based on our results, anaerobic conditions, temperature at $30^{\circ}C$, pure or crude glycerol lower than 40 g/L, and pH regulation at 7 were the optimized conditions for 1,3-PD production using K. pneumoniae DSM4799, making it more feasible to produce 1,3-PD at higher concentration and a lower price.

• Journal of Ginseng Research
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• v.29 no.3
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• pp.145-151
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• 2005

This study was carried out to determine the optimal submerged culture conditions for production of ginseng root containing germanium using plant tissue culture technology. The ginseng (Panx ginseng C.A. Meyer) .cot induced by plant growth regulators of 0.5 mg/L BAP and 3.0 mg/L NAA was cultured on SH medium and the effects of various $GeO_2$ concentrations, addition time of $GeO_2$ and pH of medium were investigated on fresh weight, saponin production and germanium accumulation in ginseng root. Optimal $GeO_2$ concentrations for fresh weight, saponin and germanium content were 10, 0 and 110ppm, respectively. When $GeO_2$ was added after 2 weeks cultivation of ginseng root, germanium content was higher than that of adding $GeO_2$ at the initial cultivation time, but saponin content and fresh weight were lower. pH 5.5 was found to be the most favorable condition for the growth of ginseng root and germanium accumulation, but saponin production was best at pH 6.0.