• KSBB Journal
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• v.13 no.3
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• pp.251-258
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• 1998

A structured kinetic model is proposed to describe cell growth and secondary metabolite, flavone glycosides, synthesis in batch suspension culture of Scutellaria baicalensis G. The model has been developed by representing the physiological state of cell described as the activity and viability which can be estimated based on the culture fluorescence. In the model, three type of cells are considered; active-viable, nonactive-viable and dead cells. Viable cell weight could be determined based on the relative fluorescence intensity. The flavone glycosides could be produced by both active-viable and non-active viable cells with a different production rate. And the model includes the cell expansion due to glucose concentration and death phase which accounts for the release of intracellular secondary metabolite into medium. Dependent variables include substrate concentration(glucose), cell mass(dry cell weight and fresh cell weight), product concentration(flavone glycosides), activity and viability. Satisfactory agreement between the model and experimental data is obtained from shake flask culture of Scutellaria baicalensis G. The proposed model can predict the cell growth and flavone glycosides synthesis as well as intermediate materials.

• KSBB Journal
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• v.11 no.3
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• pp.374-379
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• 1996

The production of extracellular mannitot by an efficient mannitol-producing bacterium, Lactobacillus sp. KY-107 was studied in shake flask culture using the modified MRS medium. Maximum mannitol production was obtained with fructose as the sole carbon source. Within 95 hours of incubation, a final concentration of 70g/L of mannitol from 100g/L fructose was obtained with an indicated yield of 86% based on fructose consumed. However, higher concentrations of fructose could not effectively be transformed to mannitol due to a lack of osmotolerance. The strain produced no other polyols such as glycerol and sorbitol as by-products. Yeast extract was best nitrogen source and high levels of inorganic phosphate up to 10g/L did not show any detrimental effect for mannitol formation. Manganese ion played important role in both cell growth and mannitol production. The optimum culture temperature and initial pH were $35^{\circ}C$ and 6-8, respectively.

• KSBB Journal
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• v.11 no.2
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• pp.246-253
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• 1996

An obligatory methanotroph Methylosinus trichosporium OB3b was cultivated for the production of poly-${\beta}$-hydroxybutyric acid(PHB) in shake-flask using liquefied natural gas(LNG) as the sole source of carbon and energy. The maximal specific growth rate decreased by 40% using LNG compared with that obtained with pure methane. This is attributed to the inhibition by ethane and propane presents in the LNG as impurities. For the production of PHB, two-stage culture separating the production stage from the growth stage was carried out. PHB accumulation was observed after switching nutrient-sufficient to nutrient-limited condition of non-carboneous component (NO3-, PO43-, K+, Na+, Fe2+, or Mg2+). The limitation of K+ or Mg2+ resulted in relatively high PHB content, but the highest content was obtained by nitrate limitation. The optimal pH and temperature for PHB accumulation was 7.0 and $30^{\circ}C$. Under the optimal condition the maximal PHB content was about 45% after 4-day cultivation.

• KSBB Journal
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• v.14 no.5
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• pp.534-538
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• 1999

For the optimization of operating conditions for plant cell suspension culture in bioreactors, effects of bioreactor types, various kinds of impellers, and aeration rates were examined using Nicotiana tabacum cells as a model system. Stirred tank bioreactor and airlift bioreactor were used for the comparison of bioreactor type. Growth rates in both bioreactors were lower than in shake flasks. In terms of final cell concentration, stirred tank bioreactor supported a little bit better growth compared to airlift bioreactor. Impeller type did not affect cell growth significantly, but it was apparent that cell size index decreased in the case of using hollowed paddle impeller. When the aeration rate was maintained at 0.3 vvm, cell growth was the best. At above 1.0 vvm, growth inhibition as well a browning was noticed. In addition, it was found that cell size index reduced proportionally to the increased of aeration rate.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.221-225
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• 1992

The possibility of using Chinese cabbage juice as a substrate for the production of Candida utilis cell mass was explored. Dry cell weight production and cell yield coefficient were 1.35-1.45 g/100 ml undiluted juice and 47-50%, respectively, when C. utilis was grown by shake flask culture at $30^{\circ}C$ for 24 hr on more than three-fold diluted Chinese cabbage juice to make the final sugar content be equal to or less than 1.0%. Supplementation of glucose(2%), $KH_2PO_4(0.2%)$ and $(NH_4)_2SO_4(0.2%)$ to three-fold diluted Chinese cabbage juice did not enhance the dry cell weight yield or the protein content of the yeast cell, while supplementation of yeast extract(0.2%) and peptone(0.2%) increased dry cell weight production and protein content but not as much as the amount of each nutrient added. It was found that Chinese cabbage juice was an excellent substrate for the cultivation of C. utilis.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.95-100
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• 1982

Torulopsis candida FRI YA-15, a selected yeast, was cultivated in alcohol distiller's waste-filtrate of dried sweet potato for microbial protein production and BOD reduction. The General composition of waste-filterate was BOD$_{5}$ 15700 ppm, COD 36800 ppm, reducing sugar 3300 ppm, total nitrogen 910 ppm, total solids 51800 ppm and ash 390 ppm. The pH of waste was 3.85. The yield to the medium of T. candida cultivated in shake-flask at $25^{\circ}C$ for 48 hrs was 3.38g/$\ell$ and effectiveness in reducing BOD$_{5}$ and COD of waste was 38.9% and 31.8%, respectively. In batch cultivation using 3 $\ell$-jar fermenter, maximum yield to the medium reached 3.2g/$\ell$after 28 hrs cultivation under the condition of temperature 35$^{\circ}C$, initial pH 4.0, aeration rate 2vvm, agitation speed 100rpm. Dry yeast was composed of crude protein 47.98% and ash 5.23%.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.324-332
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• 2016

A bacterial strain capable of hydrolyzing xylan was isolated from fermented soybean paste obtained from a domestic Buddhist temple, using enrichment culture with rice straw as a carbon source. The isolate, named YB-1301, was identified as Bacillus safensis on the basis of its DNA gyrase subunit B gene (gyrB) sequence. The xylanase productivity of strain YB-1301 was drastically increased when it was grown in the presence of wheat bran or various xylans. In particular, the maximum xylanase productivity reached above 340 U/ml in the culture filtrate from LB broth supplemented with only birchwood xylan at shake-flask level. The xylanase production was significantly induced by xylans at the stationary growth phase in LB medium containing xylan, whereas only a small amount of xylanase was constitutively produced from cells grown in LB medium with no addition of xylan. Furthermore, xylanase biosynthesis was induced more rapidly by the enzymatically hydrolyzed products of xylan than by the non-hydrolyzed xylan. In addition, the xylanase in the culture filtrate of B. safensis YB-1301 was found to have optimal activity at 55℃ and pH 6.5–7.0.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.168-176
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• 2014

The morphology of filamentous fungi closely correlates with the productivity in submerged culture. Using itaconic acid (IA) production by Aspergillus terreus as a research model, the quantitative relationship between the growth form of A. terreus and IA production was investigated. IA fermentation was scaled up from shake flasks to a 7 L stirred tank bioreactor based on the quantitative relationship. Our results demonstrated the following: (1) Three morphologies of A. terreus were formed by changing the inoculum level and shape of the flask. (2) Investigation of the effects of the three morphologies on broth rheology and IA production revealed the higher yield of IA on dry cell weight (DCW, IA/DCW) and yield of glucose on DCW (consumed glucose/DCW) were achieved during clump growth of A. terreus. (3) By varying the $KH_2PO_4$ concentration and culture temperature, the relationships between clump diameter and IA production were established, demonstrating that the yield of IA on DCW ($R^2$ = 0.9809) and yield of glucose on DCW ($R^2$ = 0.9421) were closely correlated with clump diameter. The optimum clump diameter range for higher IA production was 0.40-0.50 mm. (4) When the clump diameter was controlled at 0.45 mm by manipulating the mechanical stress in a 7 L fermentor, the yield of IA on DCW and yield of glucose on DCW were increased by 25.1% and 16.3%, respectively. The results presented in this study provide a potential approach for further enhancement of metabolite production by filamentous fungi.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1136-1140
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• 2008

The Rhodopseudomonas palustris KUGB306 hemA gene codes for 5-aminolevulinic acid (ALA) synthase. This enzyme catalyzes the condensation of glycine and succinyl-CoA to yield ALA in the presence of the cofactor pyridoxal 5'-phosphate. The R. palustris KUGB306 hemA gene in the pGEX-KG vector system was transformed into Escherichia coli BL21. The effects of physiological factors on the extracellular production of ALA by the recombinant E. coli were studied. Terrific Broth (TB) medium resulted in significantly higher cell growth and ALA production than did Luria-Bertani (LB) medium. ALA production was significantly enhanced by the addition of succinate together with glycine in the medium. Maximal ALA production (2.5 g/l) was observed upon the addition of D-glucose as an ALA dehydratase inhibitor in the late-log culture phase. Based on the results obtained from the shake-flask cultures, fermentation was carried out using the recombinant E. coli in TB medium, with the initial addition of 90 mM glycine and 120 mM succinate, and the addition of 45 mM D-glucose in the late-log phase. The extracellular production of ALA was also influenced by the pH of the culture broth. We maintained a pH of 6.5 in the fermenter throughout the culture process, achieving the maximal levels of extracellular ALA production (5.15 g/l, 39.3 mM).

• Environmental Analysis Health and Toxicology
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• v.20 no.4 s.51
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• pp.351-358
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• 2005

The n -octanol/water partition coefficient (Pow) is one of the most important parameters employed for estimating a chemiral's environmental fate and toxicity. The shake-flask method, one direct experimental method, i.1 prone to experimental artifacts for highly hydrophobic compounds. Thus, a valid method for direct determination of the Pow of highly hydrophobic compounds is needed. The slow -stirring method has been demonstrated to provide reliable log Pow data to log Pow greater than 5. This study was performed to evaluate the accuracy of slow- stirring experiment for determination of log Pow, particularly for highly hydrophobic compounds. 1, 2, 3, 4-tetrachlorobenzene, hexachlorobezene, 2, 2', 3, 3', 5, 5', 6, 6'-octachlorobiphenyl, decachlorobiphenyl, and p, p'-DDT (4.5$\times$0.02, 5.41$\times$0.06, 7.26$\times$0.04, 7.87$\times$0.10, and 6.03$\times$0.06, respectively. The octanol/water partition coefficient by the slow-stirring method were very similar to the literature values. These results indicate that the slow- stirring method allows for reliable determination of log Pow of highly hydrophobic chemicals.