• Journal of Animal Science and Technology
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• v.61 no.5
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• pp.260-271
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• 2019

The objective of this study was to determine the effect of different stocker management programs on skeletal muscle development and growth characteristics, satellite cell (SC) activity in growing-finishing beef cattle as well as the effects of SC-conditioned media on preadipocyte gene expression and differentiation. Fall-weaned Angus steers (n = 76; $258{\pm}28kg$) were randomly assigned to 1 of 4 stocker production systems: 1) grazing dormant native range (NR) supplemented with a 40% CP cottonseed meal-based supplement ($1.02kg{\cdot}steer^{-1}{\cdot}d^{-1}$) followed by long-season summer grazing (CON, 0.46 kg/d); 2) grazing dormant NR supplemented with a ground corn and soybean meal-based supplement fed at 1% of BW followed by short-season summer grazing (CORN, 0.61 kg/d); 3) grazing winter wheat pasture (WP) at high stocking density (3.21 steers/ha) to achieve a moderate rate of gain (LGWP, 0.83 kg/d); and 4) grazing winter WP at low stocking density (0.99 steers/ha) to achieve a high rate of gain (HGWP, 1.29 kg/d). At the end of the stocker (intermediate harvest, IH) and finishing (final harvest, FH) phases, 4 steers / treatment were harvested and longissimus muscles (LM) sampled for cryohistological immunofluorescence analysis and SC culture assays. At IH, WP steers had greater LM fiber cross-sectional area than NR steers; however, at FH, the opposite was observed (p < 0.0001). At IH, CORN steers had the lowest Myf-5+:Pax7+ SC density (p = 0.020), while LGWP steers had the most Pax7+ SC (p = 0.043). At FH, CON steers had the highest LM capillary density (p = 0.003) and their cultured SC differentiated more readily than all other treatments (p = 0.017). At FH, Pax7 mRNA was more abundant in 14 d-old SC cultures from HGWP cattle (p = 0.03). Preadipocytes exposed to culture media from proliferating SC cultures from WP cattle isolated at FH had more $PPAR{\gamma}$ (p = 0.037) and less FABP4 (p = 0.030) mRNA expression compared with NR cattle. These data suggest that different stocker management strategies can impact skeletal muscle growth, SC function, and potentially impact marbling development in growing-finishing beef cattle.

• KSBB Journal
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• v.8 no.5
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• pp.473-477
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• 1993

Up to now, 10% Fetal Bovine Serum(FBS(V/V)) was added to basal medium for the cultivation of hybridoma. For the cultivation of hybridoma cell line, CH07E02, against colon cancer, serum concentration was reduced to 3% FBS without influence on cell growth and maximum cell concentration. By the addition of cell growth promoting substances-insulin (I), pyruvate (P), oxaloacetate(O), Pluronic F-68(P) and 2-mercaptoethanol(2-ME)-to 1% FBS medium, a cell density higher than that with 1% FBS medium alone was achieved. FBS 3% medium was replaced by very cheap 2% Calf Serum (CS) medium without influence on cell growth rate and concentration. Cells grew vigorously in 0.5% CS＋IPOP medium. This composition was used during suspension culture and exhibited good viability and high specific growth rate.

• KSBB Journal
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• v.5 no.3
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• pp.307-313
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• 1990

A microcomputer-aided fermentation system was constructed for high density fed-batch culture using dissolved oxygen(DO) as a substrate feeding indicator. DO signal was processed prior to aquisition to computer. Agitation speed and oxygen flow rate was changed stepwisely to maintain DO value at a constant level. Agitation speed was controlled by the output signal of D/A converter. Oxygen flow rate was controlled by a flow rate control valve connected to a stepping motor. Substrate was fed with a feeding pump operated by the abrupt increase of DO signal. Methylobacillus sp. SK1 was cultivated to test the system and 16.53g/l of cell density was obtained after 10 hr.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.241-244
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• 2000

Continuous $H_2$ production from CO and water was studied in a trickle bed reactor(TBR) using Rhodopspedomonas palustris P4. To achieve high cell density, R. palustris P4 were cultivated by a fed-batch culture mode under chemoheterotrophic and aerobic condition, and final cell concentration was 13 g/L. TBR could provide sufficient residence time for CO to contact with cell suspension circulating TBR. The maximum CO uptake rate was found to be 16 mmol/L/hr at gas retention time of 50 min and CO partial pressure of 0.4 atm. In our correlation of the experimental data with mathematical model of TBR, the TBR operation with P4 was found to be lie in an intermediate state between mass transfer limitation and kinetic limitation. Due to the high cell density as well as hydrogen production activity in this study, TBR operation showed a superior performance to other previous reports on microbial hydrogen production.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.374-377
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• 2003

Hybridoma cells were adapted in media containing up to 80 mM $K^+$. The adapted cells obtained tolerance at high osmotic pressure and low pH. The adapted cells showed a maximum viable cell density of $1.1{\times}10^6$ cells/ml when a batch culture was progressed in a nutrient-fortified medium with Erlenmeyer flask at 450 $mOsm/kgH_2O,$ as compared to $4.8{\times}10^5$ cells/ml for non-adapted cells grown under the same conditions. The adapted cells also showed a maximum viable cell density of $7.8{\times}10^5$ cells/ml with the same method at initial pH 7.0 as compared to $5.3{\times}10^5$ cells/ml for non-adapted cells. Adaptation of animal cells at high $K^+$ levels may therefore lead to an improvement of their performance at limited conditions.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.3
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• pp.194-199
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• 2001

Chlorella kessleri cultivated in artificial wastewater using diurnal illumination of 12h light/12h dark (L/D) cycles. The inoculum density was 10(sup)5 cells/mL and the irradiance in light cycle was 45$\mu$mol㎡s(sup)-1 at the culture surface. As a control culture, another set of flasks was cultivated under continuous illumination. Regardless of the illumination scheme, the total organic carbon (TOC) and chemical oxygen demand (COD) was reduced below 20% of the initial concentration within a day. However, cell concentration under the L/D lighting scheme was lower tan that under the continuous illuminating scheme. Thus the specific removal rate of organic carbon under L/D cycles was higher than that under continuous illumination. This result suggested that C. kessleri grew chemoorganotrophically in the dark periods. After 3 days, nitrate was reduced to 136.5 and 154.1mg NO$_3$-N/L from 168.1mg NO$_3$-N/L under continuous illumination and under diurnal cycles, respectively. These results indicate nitrate removal efficiency under continuous light was better than that under diurnal cycles. High-density algal cultures using optimized photobioreactors with diurnal cycles will save energy and improve organic carbon sources removal.

• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.257-263
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• 1998

Alcaligenes eutrophus was successfully recovered from high cell density broth by pre-treatment with Fe-based coagulants. An inorganic coagulant, Fe$_2$(SO$_4$)$_3$, and a polymerized coagulant, Ferix-3, were used. Good coagulation was observed in broad pH range of 3 to 13, the floe size was increased with increasing pH of culture broth. The optimum pH of fermentation broth for cell recovery was 10 to 13. The optimum coagulant dosages to recover cells with 95% cell recovery were increased with increasing cell concentration. Optimal coagulant dosage was lower when the polymerized coagulant was used rather than the inorganic coagulant. The coexistence of NH$_4$$\^$+/ was increased coagulant requirement, and the coagulant requirement was 0.066g Fe$_3$$\^$+//g NH$_4$$\^$+/.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.211-215
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• 2003

When Saccharomyces cerevisiae MTY62, a high-RNA content yeast, was cultivated by fed-batch mode feeding molasses and com steep liquor, the cell density less than 45g-DCW/L and the RNA content less than 140mg/g-cell were obtained, indicating that unknown compounds inhibiting the cell growth and RNA accumulation are contained in the molasses. Therefore, in order to obtain higher levels of cell density and RNA content, $Ca^{++}$, $Cu^{++}$and $K^{+}$ ions in molasses were removed by pretreatments of molasses with various agents such as IonClear BigBead, $Na_2$$HPO_4$, $H_2$$SO_4$, citric acid, $K_2$$HPO_4$, and EDT A. Among them, IonClear BigBead, $Na_2$$HPO_4$, and EDTA gave the highest $Ca^{++}$ removal efficiency of about 60-90%. In the batch culture with pretreated molasses, the cell concentration of 18.6g-DCW/I and RNA concentration of 3127 mg/I, maximum specific growth rate of 0.459$h^{-1}$ , and specific consumption rate of reducing sugar of 1.28g-sugar/g-cell-h were obtained, which are about 10%, 17%,47%, and 36% higher levels, respectively, over the batch culture with untreated molasses.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.551-553
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• 2000

A strong constitutive $P_{JH}$ promoter from Bacillus was applied to overexpress the endoxylanase gene in B. subtilis. The expression plasmid, pHJKJ4, was designed to contain the $P_{JH}$ promoter and endoxylanase promoter ($P_B$), and introduced into B. subtilis DB104. Through batch fermentation of the trasformant cell on a maltose medium, endoxylanase was produced in a growth-associated manner as the predominant protein. The total activity reached about 600 unit/ml at the end of the cultivation, which corresponded to 698 mg endoxylanase protein/l with a specific activity of 860 unit/mg protein. It was also found that the segregational plasmid instability was less than 30% and most of the endoxylanase activity was detected in the culture medium. This result suggests that the secretory production of endoxylanase can be significantly enhanced with the use of the $P_{JH}$ promoter and high-cell density culture techniques, quantitatively as well as qualitatively.

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.474-481
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• 2009

A novel microorganism, designated as LG12, was isolated from soil based on its ability to use acrylic acid as the sole carbon source. An electron microscopic analysis of its morphological characteristics and phylogenetic classification by 16S rRNA homology showed that the LG12 strain belongs to Rhodococcus erythropolis. R. erythropolis LG12 was able to metabolize a high concentration of acrylic acid (up to 40 g/l). In addition, R. erythropolis LG12 exhibited the highest acrylic acid-degrading activity among the tested microorganisms, including R. rhodochrous, R. equi, R. rubber, Candida rugosa, and Bacillus cereus. The effect of the culture conditions of R. erythropo/is LG12 on the production of 3-hydroxypropionic acid (3HP) from acrylic acid was also examined. To enhance the production of 3HP, acrylic acid-assimilating activity was induced by adding 1 mM acrylic acid to the culture medium when the cell density reached an $OD_{600}$ of 5. Further cultivation of R. erythropo/is LG 12 with 40 g/l of acrylic acid resulted in the production of 17.5 g/l of 3HP with a molar conversion yield of 44% and productivity of 0.22 g/l/h at $30^{\circ}C$ after 72 h.