• Biotechnology and Bioprocess Engineering:BBE
• /
• v.5 no.5
• /
• pp.382-385
• /
• 2000

A mathematical model was developed, based on the time dependent changes of the specific growth rate, for prediction of the typical microbial cell growth in batch cultures. This model could predict both the lag growth phase and the stationary growth phase of batch cultures, and it was tested with the batch growth of Trichoderma reesei and Lactobacillus delbrueckii.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.7
• /
• pp.1114-1118
• /
• 2015

Microbial fuel cells (MFCs) have gathered attention as a novel bioenergy technology to simultaneously treat wastewater with less sludge production than the conventional activated sludge system. In two different operations of the MFC and aerobic process, microbial growth was determined by the protein assay method and their biomass yields using real wastewater were compared. The biomass yield on the anode electrode of the MFC was 0.02 g-COD-cell/gCOD-substrate and the anolyte planktonic biomass was 0.14 g-COD-cell/g-COD-substrate. An MFC without anode electrode resulted in the biomass yield of 0.07 ± 0.03 g-COD-cell/g-CODsubstrate, suggesting that oxygen diffusion from the cathode possibly supported the microbial growth. In a comparative test, the biomass yield under aerobic environment was 0.46 ± 0.07 g-COD-cell/g-COD-substrate, which was about 3 times higher than the total biomass value in the MFC operation.

• Journal of Environmental Health Sciences
• /
• v.33 no.2 s.95
• /
• pp.115-122
• /
• 2007

Methanol extracts of Perilla and Mugwort were stepwise extracted with hexane, chloroform, ethyl acetate, butanol and water. Anti-microbial activities and inhibitory effect on growth of oral tumor cell of each extract were investigated. Each extracts of Perilla and Mugwort were investigated to anti-microbial effects on oral microbes by means of agar diffusion method and MIC. These results suggest that the hexane extracts of Perilla and Mugwort have antimicrobial activities against S. mutans and potent inhibitory Effect to KB cell growth.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.5 no.3
• /
• pp.207-210
• /
• 2000

When endothelial cells isolated isolated from human umbilical venis were cultred for 6dary using 96-well microplates, the final cell density in each was fiund not to be the same although the medium composition of each well was exactly the same. Cell growth in the wells located at the periphery of a microplate was low, while that in the central area of the plate was high. A possible cause for different rate of growth was proposed as the uneven concentration of oxygen in the culture medium of each well.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.5 no.2
• /
• pp.106-109
• /
• 2000

Vascular endothelial cells (EGs) are usually difficult to culture to culture in a large scale because of their complicated requirements for cell growth. As the vascular endothelial growth factor (VEGF) is a key growth factor in the EC culture, we transfected human umbilical vein endothelial cells (HUVEC) using a plasmid containing VEGF gene and let them grow in a culture medium eliminated an important supplement, endothelail cell growth supplement(ECGS). The expression of VEGF by HUVEC tansfected with Vegf GENE was not enough to stimulate the growth of HUVEC, only 40% of maximum cell density obtainable in the presence of ECGS. However, when the culture medium was supplied with 2.5 ng/ml of basic fibroblast growth factor (bFGF), a synergistic effect effect of VEGE and bFGF was observed. In this case, the final cell density was recovered was recovered up to about 78% of maxium value.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.3
• /
• pp.195-199
• /
• 1994

Immunostimulation effects of the cell wall components isolated from Lactobacillus plantarum were investigated by studying the macrophage s tumorcidal activity, splenocyte proliferation, anticomplementary activity and the inhibition of peritoneal tumor cell growth measured with ICR mice inoculated with sarcoma 180. The immunopotentiating cell wall components were a complex of peptidoglycan and exopolysaccharides. The tumorcidal activity of macrophage against Yacl and B16 tumor cells was enhanced when the cell wall components were added into the macrophage s culture medium. They also stimulated splenocytes to proliferate up to the same level as when the concanavalin A was added into the splenocyte's culture medium. The complementary activity was inhibited by 50% when the cell wall components were incubated with the sheep red blood cells treated with hemolysin and guinea pig complement. This result confirmed that the cell wall components had an antitumor effect, because the anticomplementary activity is usually accompanied by an antitumor activity at the same time. This fact was confirmed again by the inhibition of the growth of sarcoma 180 when the cell wall components were injected intraperitoneally into ICR mice inoculated with sarcoma 180. As a result, it is concluded that the cell wall components isolated from Lactobacillus plantarum had multifunctional immunostimulation effects in vitro and in vivo.

• Journal of Microbiology and Biotechnology
• /
• v.17 no.1
• /
• pp.110-115
• /
• 2007

Electrochemically active bacteria were successfully enriched in an electrochemical cell using a positively poised working electrode. The positively poised working electrode (+0.7 V vs. Ag/AgCl) was used as an electron acceptor for enrichment and growth of electrochemically active bacteria. When activated sludge and synthetic wastewater were fed to the electrochemical cell, a gradual increase in amperometric current was observed. After a period of time in which the amperometric current was stabilized (generally 8 days), linear correlations between the amperometric signals from the electrochemical cell and added BOD (biochemical oxygen demand) concentrations were established. Cyclic voltammetry of the enriched electrode also showed prominent electrochemical activity. When the enriched electrodes were examined with electron microscopy and confocal scanning laser microscopy, a biofilm on the enriched electrode surface and bacterium-like particles were observed. These experimental results indicate that the electrochemical system in this study is a useful tool for the enrichment of an electrochemically active bacterial consortium and could be used as a novel microbial biosensor.

• Journal of Environmental Health Sciences
• /
• v.33 no.1 s.94
• /
• pp.21-29
• /
• 2007

Paeonia lactiflora was stepwise extracted with hexane, chloroform, ethyl acetate, butanol and water. Anti-microbial activity of each extract was investigated. Methanol extract of P. lactiflora revealed anti-microbial activity against S. mutans, C. albicans, and S. aureus. Also, hexane fraction revealed anti-bacterial activity against S. mutans and ethyl acetate fraction acted as potent anti-microbial agent on C. albicans and S. aureus. The relative growth ratio(RGR) of hexane fraction of P. lactiflora against S. mutans were determined as 77.8% in concentration of 0.125 mg/ml, 98.46% in 0.25 mg/ml and 100% in 0.5 mg/ml. The ethyl acetate fraction of P. lactiflora revealed RGR against C. albicans as 52.5% in concentration of 0.125 mg/ml, 60.83% in 0.25 mg/ml and 78.33% in 0.5 mg/ml. It indicate that increasing concentration increase RGR. The measured minimal inhibitory concentration(MIC) of hexane fraction on S. mutans KCTC 5316 strain was 0.5 mg/ml and MIC of ethyl acetate fraction on C. albicans KCTC 7270 was 2.0 mg/ml. The experiment of inhibition to growth of KB roll(oral squamous cell carcinoma) result 61.9% in butanol, 76.7% in hexane extract of P. lactiflora. The hexane extract exhibit potent inhibition effect to the growth of KB cell. These results suggest that the hexane extract of Paeonia lactiflora has antimicrobial activity against S. mutans and has preventive effect to dental caries in addition to potent inhibition to KB cell growth.

• Microbiology and Biotechnology Letters
• /
• v.24 no.6
• /
• pp.749-755
• /
• 1996

From the soil collected from provincial area of South Korea, a microorganisms which have been shown good growth in the minimal poultry feces extract medium was isolated. Supplement of glucose to the poultry feces extract medium helped the complete uptake of soluble protein by microorganism. Uric acid in the poultry feces extract medium could be completely degraded during the microbial growth. Maximum cell growth (3.8 $\times$ 10$^{9}$ CFU/ml) obtained at 36 hours of incubation after inoculation. Uric acid was degraded faster in minimal medium than in the glucose complement medium. VFA (volatile fatty acid), which are known as major compounds of poultry feces odor, were almost removed from the minimal poultry feces extract medium. Glucose supplement to the minimal medium enhanced the growth of microbial cells. Addition of 4% of glucose and 4% of neopeptone to the minimal poultry feces extract medium helped the maximal growth of cells.

• Food Science and Biotechnology
• /
• v.15 no.5
• /
• pp.664-671
• /
• 2006

Modeling the growth kinetics of lactic acid bacteria (LAB), one of the most valuable microbial groups in the food industry, has been actively pursued in order to understand, control, and optimize the relevant fermentation processes. Most modeling approaches have focused on the development of single population models. Primary single population models provide fundamental kinetic information on the proliferation of a primary LAB species, the effects of biological factors on cell inhibition, and the metabolic reactions associated with cell growth. Secondary single population models can evaluate the dependence of primary model parameters, such as the maximum specific growth rate of LAB, on the initial external environmental conditions. This review elucidates some of the most important single population models that are conveniently applicable to the LAB fermentation analyses. Also, a well-defined mixed population model is presented as a valuable tool for assessing potential microbial interactions during fermentation with multiple LAB species.