• KSBB Journal
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• v.25 no.5
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• pp.471-477
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• 2010

In order to improve bio-ethanol productivity by various cultivation methods in this paper, the culture modes using food wastes, such as batch culture, high-cell-density fermentation, SSF (simultaneous saccharification and fermentation) by fill & draw, continuous culture by fill & draw were performed and their productivities were compared. SSFs by fill & draw were performed by continuous decompression using 1 L evaporator system, and by 10 L bioreactor without decompression. In addition, the continuous cultures by fill & draw mode using SFW (saccharafied food wastes) medium were performed by changes of 40% culture broth with intervals of 12 h (0.03 $h^{-1}$), 6 h (0.07 $h^{-1}$), 3 h (0.13 $h^{-1}$). Consequently, productivities of bio-ethanol were 2.52 g/L-h and 1.30 g/L-h in batch culture and high- cell-density fermentation, respectively. The productivities of SSF by fill & draw showed 2.24 g/L-h and 2.03 g/L-h in continuous decompression with 1 L evaporator and 10 L bioreactor without decompression, respectively. Also, the productivities in continuous culture by fill & draw modes showed 2.02 g/L-h, 4.07 g/L-h and 6.25 g/L-h by medium change with intervals of 12 h, 6 h, and 3 h, respectively. In conclusion, the highest ethanol productivity was obtained in the continuous culture mode by fill & draw with dilution rate of 0.13 $h^{-1}$.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1624-1631
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• 2021

Prodigiosin as a high-valued compound, which is a microbial secondary metabolite, has the potential for antioxidant and anticancer effects. However, the large-scale production of functionally active Hahella chejuensis-derived prodigiosin by fermentation in a cost-effective manner has yet to be achieved. In the present study, we established carbon source-optimized medium conditions, as well as a procedure for producing prodigiosin by fermentation by culturing H. chejuensis using 10 L and 200 L bioreactors. Our results showed that prodigiosin productivity using 250 ml flasks was higher in the presence of glucose than other carbon sources, including mannose, sucrose, galactose, and fructose, and could be scaled up to 10 L and 200 L batches. Productivity in the glucose (2.5 g/l) culture while maintaining the medium at pH 6.89 during 10 days of cultivation in the 200 L bioreactor was measured and increased more than productivity in the basal culture medium in the absence of glucose. Prodigiosin production from 10 L and 200 L fermentation cultures of H. chejuensis was confirmed by high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analyses for more accurate identification. Finally, the anticancer activity of crude extracted prodigiosin against human cancerous leukemia THP-1 cells was evaluated and confirmed at various concentrations. Conclusively, we demonstrate that culture conditions for H. chejuensis using a bioreactor with various parameters and ethanol-based extraction procedures were optimized to mass-produce the marine bacterium-derived high purity prodigiosin associated with anti-cancer activity.

• KSBB Journal
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• v.9 no.2
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• pp.211-223
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• 1994

In fermentations with a 4-liter stirred tank bioreactor, a better than two-fold enhancement of the gas-liquid mass transfer coefficient$(k_La)$ in the celite-immobilized fungal cultures of Tolypocladium in flatum over the parallel conventional free-cell was observed at identical biomass concentrations, despite the higher specific oxygen uptake rate of the immobilized fungi during exponential growth. As a result oxygen sufficient conditions, i. e., dissolve oxygen(D.O.) concentrations exceeding 75% air saturation, could be maintained throughout exponential growth period of the immobilized culture, in contrast to the suspended fungal culture, whose D.O. levels fell below 50% air saturation. A linear monotonic dependence of $k_La$ upon impeller agitaion rate was found for both immobilized and conventional cultivation modes over a range of 250 to 550rpm, the slope being a function of biomass concentration for the free but not for the immobilized cell system In contrasts oxygen transfer rate was a much weaker function of aeration rate up to about 2.5 vvm for both culture configurations. Above this level, aeration rate had no further effect on the mass transfer. In addition, the immobilized cultures sustained good morphological and physiological states, leading to almost two times higher cyclosporln A (CyA) productivity overt the parallel free cell system. These experiments suggest that the celite-immobilized fungal system in a stirred tank reactor has considerable promise for scaling up cyclosporin A production in terms of high-density cultivation.

• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.363-369
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• 2009

This study was carried out to investigate the effect of ${NO_3}^-$ and ${NH_4}^+$ on the adventitious root growth and eleuthroside synthesis of Eleutherococcus koreanum in 5 L-bioreactor culture. The change in the medium components was also measured during culture. The fresh weignt of adventitious root reached to the highest level of 30.8 g FW/L in the presence of both 50 mM ${NO_3}^-$ and 10 mM $NH_4^+$, representing 3.6-fold increase compared to the 60 mM ${NH_4}^+$ alone. However, as the increase of the portion of ${NH_4}^+$, the root growth was decreased. However, the maximum eleutheroside B, E and E1 contents were $57.3{\mu}g/g$ DW, $188.4{\mu}g/g$ DW and $47.3{\mu}g/g$ DW, with 30 mM, 60 mM and 15 mM total nitrogen source, respectively. Fresh weight of adventitious root increased up to 6.8-fold of inoculum size within 9 weeks. The amounts of ${NH_4}^+$, $K^+$, ${NO_3}^-$ and ${PO_4}^-$ were decreased during culture periods. Based on these results, we suggest that various further studies are required to increase the biomass and the useful secondary metabilites.

• Applied Biological Chemistry
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• v.39 no.1
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• pp.1-8
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• 1996

A one-stage, continuous-flow bioreactor with both immobilized and suspended cells was used to investigate the roles of lipid supplements in ethanol production by Saccharomyces cerevisiae. The reactor performance and the level of alcohol dehydrogenase(ADH) activities of the suspended cells, grown under various conditions, were measured. When ergosterol and/or oleic acid were added with surfactants to the yeast culture grown under non-aerated conditions, remarkable increases in ethanol production and cell growth was achieved, but specific ADH activities were not affected. Especially, no difference of specific ADH activities of the suspended cells grown under aerated and non-aerated condition was observed. The addition of the surfactant as a supplement also resulted in significant increases in ethanol production, cell growth, and specific ADH activity. When ergosterol and oleic acid were added to the yeast culture exposed to higher ethanol concentration($>40\;g/{\ell}$) level, ethanol production, cell growth, and specific ADH activity were increased, but the addition of surfactant was as effective as at lower ethanol concentration level. The results indicated that lipid supplements were more effective at higher ethanol concentration level than at lower ethanol concentration level during ethanol production. ADH isozyme patterns of the yeast cultures grown under various conditions on starch gel electrophoresis showed only one major band, probably ADH I. The migrating distance of the major isozyme, however, varied slightly according to the culture conditions of the cells. No apparent correlation was found between specific ADH activity and amount of ethanol produced. Cell mass was more important factor for ethanol production than specific ADH activity of the cells.

• Journal of Microbiology and Biotechnology
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• v.11 no.1
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• pp.40-49
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• 2001

The present work presents a novel approach for the dynamic quantification of respiration rates on a small scale by using lysine-producing Corynebacterium glutamicum ATCC 21253. Cells sampeld from batch cultures at different times were incubated ina 12-ml scale bioreactor equipped with a membrane mass spectrometer. Under dynamic conditions, gas exchange across the gas-liquid phase, specific respiration rates, and RQ values were precisely measured. For this purpose, suitable mass balances were formulated. The transport coefficients for $O_2$ and $CO_2$, crucial for calculating the respiration activity, were determined as $k_La_{O2}=9.18h^{-1}$ and $k_La_{CO2}=5.10h^{-1}$ at 400 rpm. The application of the proposed method to batch cultures of C. glutamicum ATCC 21253 revealed the maximum specific respiration rates of $q_{O2}=8.4\;mmol\;g^{-1}h^{-1}\;and\;q_{CO2}=8.7\;mmol\;g^{-1}h^{-1}$ in the middle of the exponential growth phase after 5 h of cultivation. When the cells changed from growth to lysine production due to the depletion of the essential amino acids theonine, methionine, and leucine, $q_{O2}\;and\;q_{CO2}$ decreased significantly and RQ increased. The respiration data exhibited an excellent agreement with previous cultivations of the strain [13]. This confirms the potential of the developed approach to realistically reflect the metabolic activities of cells at their point of sampling. The short-term influence of added threonine, methionine, and leucine was highest during the shift from growth to lysine production, where $q_{O2}\;and\;q_{CO2}$ increased 50% within one minute after the pulse addition of these compounds. Non-growing, yet lysine-producing cells taken from the end of the batch cultivation revealed no metabolic stimulation with the addition of threonine, methionine, and leucine.

• KSBB Journal
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• v.27 no.3
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• pp.186-194
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• 2012

Various human host cell lines, which are more effective than the other original human cell lines, have been developed and used. Highly efficient human cell line can be obtained from the fusion between human embryonic kidney 293 (HEK293) and human Burkitt's lymphoma cells (Namalwa). Fused cell line has the advantages of both cell lines such as the high transfection efficacy of HEK293 cells and the constitutive expression of Epstein-Barr virus (EBV) genome which is related with high expression of target protein and anti-apoptotic growth of Namalwa cells. In this study, characterization of two original cell lines was performed by using design of experiment (DOE) considering cell maintenance, media development, optimization of culture condition, and scale-up. The formation of aggregates was apparent with high glutamine concentration at more than 6 mM. Supplementation of hydrolysates showed positive effects on the growth performances of HEK293 cells. On the contrary, Namalwa cells showed negative results. It was confirmed that Namalwa cells were more sensitive to lower temperature at $35^{\circ}C$ and hyperosmotic condition over 260 mOsm/kg. In addition, both cell lines showed limited growth in 3-L bioreactor due to shear stress.

• Journal of Plant Biotechnology
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• v.30 no.2
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• pp.173-177
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• 2003

The effect of IBA and NAA on adventitious root cultures of Panax ginseng C.A. Mater were investigated. Results indicated differences in growth and development of the roots according to 5mg/L IBA and 2mg/L NAA. IBA resulted in a normal root development and a higher growth compared to NAA. The roots formed on NAA-containing media were shorter and thicker than those in IBA, showing a hypertrophy of the root tip. NAA induced more than 1.6 times higher ethylene production compared to IBA, which caused inhibition of the root growth. Under the ventilation, in the other hand, on difference was observed in ethylene concentration and the root growth between IBA and NAA treatments. Under ventilation ethylene production was not detected until 10 days of culture, while detected from the initial stage under on ventilation. The results suggested the importance of ventilation during the culture for the growth and development of ginseng adventitious roots.

• Advances in environmental research
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• v.9 no.2
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• pp.109-121
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• 2020

Phenol is frequently present as the hazardous pollutant in petrochemical and pesticide industry wastewater. Because of its high toxicity and carcinogenic potential, a proper treatment is needed to reduce the hazards of phenol carrying effluent before being discharged into the environment. Phenol biodegradation with microbial consortium offers a very promising approach now a day's. This study focused on the formulation of phenol degrading bacterial consortium with three bacterial isolates. The bacterial strains Bacillus cereus strain VCRC B540, Bacillus cereus strain BRL02-43 and Oxalobacteraceae strain CC11D were isolated from detergent contaminated soil by soil enrichment technique and was identified by 16s rDNA sequence analysis. Individual cultures were degrade 100 μl phenol in 72 hrs. The formulated bacterial consortium was very effective in degrading 250 μl of phenol at a pH 7 with in 48 hrs. The study further focused on the analysis of the products of biodegradation with Fourier Transform Infrared Spectroscopy (FT/IR) and Gas Chromatography-Mass Spectroscopy (GC-MS). The analysis showed the complete degradation of phenol and the production of Benzene di-carboxylic acid mono (2-ethylhexyl) ester and Ethane 1,2- Diethoxy- as metabolic intermediates. Biodegradation with the aid of microorganisms is a potential approach in terms of cost-effectiveness and elimination of secondary pollutions. The present study established the efficiency of bacterial consortium to degrade phenol. Optimization of biodegradation conditions and construction of a bioreactor can be further exploited for large scale industrial applications.

• Microbiology and Biotechnology Letters
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• v.47 no.2
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• pp.242-249
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• 2019

Biosynthesis of indole-3-acetate (IAA) from L-tryptophan via indole-3-pyruvate pathway requires three enzymes including aminotransferase, indole-3-pyruvate decarboxylase, and indole-3-acetate dehydrogenase. To establish a bio-based production of IAA, the aspC, ipdC, and iad1 from Escherichia coli, Enterobacter cloacae, and Ustilago maydis, respectively, were expressed under control of the tac, ilvC, and sod promoters in C. glutamicum. Cells harboring ipdC produced tryptophol, indicating that the ipdC product is functional in this host. Analyses of SDS-PAGE and enzyme activity revealed that genes encoding AspC and Iad1 were efficiently expressed from the sod promoter, and their enzyme activities were 5.8 and 168.5 nmol/min/mg-protein, respectively. The final resulting strain expressing aspC, ipdC, and iad1 produced 2.3 g/l and 7.3 g/l of IAA from 10 g/l L-tryptophan, respectively, in flask cultures and a 5-L bioreactor.