• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1053-1056
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• 2011

Optimal conditions for a high cell density fermentation were investigated in a recombinant Escherichia coli producing salmosin, a platelet aggregation inhibitor. The optimized carbon and nitrogen sources were glycerol 10 g/l, yeast extract 30 g/l, and bacto-tryptone 10 g/l, yielding the dry cell weight (DCW) of 10.61 g/l in a 500 ml flask culture. The late-stage induction with 1% L-arabinose in a 5 l jar fermentor showed the highest DCW of 65.70 g/l after 27 h of the fed-batch fermentation. Around 2,200 mg/l of the protein was expressed as an inclusion body that was then refolded to obtain the active salmosin of 96 mg/l. We also confirmed the inhibitory activity against platelet aggregation of the active salmosin from the high cell density fermentation.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.340-345
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• 2010

The culture variables were optimized to increase 1,3-dihydroxyacetone (DHA) production by Gluconohacter oxydans ZJB09112 in shake flasks and bubble column bioreactors. After fermentation in the optimized medium (g/l: yeast extract 5, glycerol 2.5, mannitol 22.5, $K_2HPO_4$ 0.5, $KH_2PO_4$ 0.5, $MgSO_4{\cdot}7H_2O$ 0.1, $CaCO_3$ 2.0, pH 5.0), when five times of glycerol feeding were applied, $161.9{\pm}5.9\;g/l$ of DHA was attained at a $88.7{\pm}3.2%$ conversion rate of glycerol to DHA.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.245-246
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• 2000

Agrobacterium sp. ATCC 31750( formerly Alcaligenes faecalis subsp myxogenes) was used to produce curdlan. Since the curdlan is secondary metabolite, it is important for curdlan production to increase cell concentration. The fedbatch operation was used to increase cell concentration with addition of carbon and nitrogen sources. When the initial sucrose concentration was 20g/L, it was consumed in 24 hrs and the cell concentration was 6g/L in a batch culture. The sucrose solution(200g/L) was fed to control the sucrose concentration above 10g/L.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.260-265
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• 2005

In the previous research about ethanol production, we confirmed that SFW(saccharified foodwastes) medium(0.56g-ethanol/g-glucose) is mere efficient than YM medium(0.538g-ethanol/g-glucose). Ethanol production using SFW needs large enzyme cost due to the enzymatic hydrolysis of foodwastes, although the enzymes was obtained from our economical enzyme production methods, using the intact whole culture broth of Trichoderma harzianum FJ1. Therefore, in this research we used synchronous saccharification and fermentationmethod to produce ethanol using foodwastes. Ethanol production yield was 0.45g-ethanol/g-reducing sugar in synchronous saccharification and for-mentation by a fed-batch mode.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.4
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• pp.242-246
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• 2000

Human lipocortin-I was expressed as a secretory product by Saccharomyces cerevisiae harboring an expression system consisting of GAL10 promoter, inulinase signal sequence and lipocortin-I terminator. Fed-batch fermentation was carried out to overproduce recombinant human lipocortin-I. The culture medium was desalted and concentrated by ultrafiltration, and then subjected to hydroxyapatite column chromatography. The lipocortin-I was purified to >98% purity by single-step hydroxyapatite column chromato-graphy. However, it was found that the purified lipocortin-I was a proteolytically-cleaved form which was cleaved immediately after the basic amino acid Lys26.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.722-725
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• 1999

Filamentation-suppressed recombinant Escherichia coli strain harboring the Alcaligenes latus polyhydroxyalkanoate (PHA) biosynthesis genes and the E. coli ftsZ gene was constructed and cultivated for the production of poly(3-hydroxybutyrate) [P(3HB)] with high concentration and high content. By the pH-stat fed-batch culture of this recombinant E. coli strain XL1-Blue(pJC5), the final cell concentration and P(3HB) concentration obtained in 44.25h were 172.2g cell dry weight/l and 141.9g P(3HB)/l, respectively, resulting in productivity of 3.21g P(3HB)/l-h. More importantly, the P(3HB) content obtained was 82.4 wt %, which was significantly higher than that obtained with the recombinant E. coli harboring only the PHA biosynthesis genes.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.55-58
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• 2005

Sophorolipid was produced by Candida bombicola ATCC 22214 from soybean dark oil, a byproduct of soybean oil processing. With a fed-batch culture of C. bombicola for 7 days, 90 g/l of sophorolipid was obtained. The CMC (critical micelle concentration) and minimum surface tension of the sophorolipid in aqueous solution were found to be 150 mg/l and 48 mN/m, respectively. The dispersion capability of sophorolipid was higher than that of the chemical surfactants such as SDS and Brij30. The molar solubility ratio (MSR) of 4-methylnaphthalene was 0.2. Linoleic and oleic acids were the main constituents of the fatty acid composition of the sophorolipid. The sophorolipid showed antimicrobial activity against Propionibacterium acne and Bacillus subtilis.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.628-631
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• 2000

The timing of poly(3-Hydroxybutyrate) (PHB) biosynthesis was controlled by varying the agitation speed of a stirred tank fermentor during the pH-stat fed-batch culture of recombinant Escherichia coli strain GCSC 6576 harboring pSYL107. Using a concentrated whey solution containing ca. 200 g/l lactose as the nutrient feed, the PHB content was only 57% after 35h due to volumetric limitation of the fermentor. However, by limiting the oxygen by maintaining the agitation speed at 300 rpm, the final PHB content increased to 70% after 70h with a cell concentration of 15 g/l. When the agitation speed was increased up to 500 rpm, a cell concentration of 31 g/l with 80% PHB was obtained after 52h. A further increase in the maximum agitation speed increased the cell concentration, PHB concentration, and PHB productivity, however, the PHB content decreased to 56-58%.

• KSBB Journal
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• v.7 no.4
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• pp.296-301
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• 1992

A Pseudomonas fluorescens was selected from mushrooms and studied in both batch and fed-batch cultures in order to get maximal biomass concentration. P. fluorescens is an aerobic bacterium and antagonistic to Pseudomonas tolaasii which causes blotch disease on the mushroom cap. P fluarescens and P. tolaasii were identified by Gram staining, gelatin liquefaction, oxidase test, etc. and were characterized by pigment production, temperature sensitivity, salt tolerance and rapid pitting test, etc., Celts of P. fluorescens well in medium containing 30g/L of glucose, whereas the growth was inhibited at the glucose levels at higher than 30g/L. The highest values of specific growth rate and productivity were obtained when using 10g/1 of yeast extract. Optimum concentrations of $NH_4Cl$ and ${(NH_4Cl)}_2SO_4$ for culture were found to be 1.0g/L and 0.1g/L respectively. Optimum concentration of $MgSO_4{\cdot}7H_2O$ used as a sulfursource was 1.0g/L. It was also found that the cell concentrations reached the maximum level when grown on the medium containing 1.0g/L of $KH_2PO_4$ and 0.1g/L of $CaCl_2$. Also, the optimum culture conditions were $30^{\circ}C$ and pH 6.0. Cultivation of P. fluarescens at high dissolved oxygen (DO) concentration led to a decrease of bacterial productivity in batch culture. Maximum productivity was achieved at 40% DO concentration.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.532-539
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• 2004

For efficient lincomycin production from Streptomyces lincolnensis L1245, various vegetable oils, natural nitrogen sources, and surfactants were investigated at the pilot-scale level in the flask. Olive oil as the sole carbon source was the most suitable one for producing lincomycin. When 20 g/lof olive oil was used, the lincomycin concentration and lipase activity reached 1.01 g/land 182 U/ml, respectively, after 5 days of culture. Among the various unsaturated fatty acids, when linolenic acid was used, the cell growth and lincomycin production were markedly decreased. On the other hand, when 0.2 g/l of oleic acid was added to the culture broth, the maximum lincomycin concentration was 1.0 g/l, which was about 1.7-fold higher than that obtained without the addition of oleic acid. Among the various natural nitrogen sources, pharmamedia or soybean meal was the most suitable nitrogen source. In particular, in the case of a mixture of 10 g/l of pharmamedia and soybean meal, 1.5 g/l of lincomycin concentration and 220 U/ml of lipase activity were obtained. When Span 180 was used as the surfactant, lincomycin production, lipase activity, and oil consumption increased. The correlation between the consumption rates of oil and lincomycin production in a culture using olive oil as the sole carbon source was also investigated. The lincomycin production depended on the consumption rate of olive oil. Using these results, fed-batch cultures for comparing the use of olive oil and starch as a conventional carbon source were carried out in a 5-1 fermentor. When olive oil was used as the sole carbon source, 34 g/l of olive oil was consumed after 7 days of culture. The maximum lincomycin concentration was 3.0 g/l, which was about 2.0-fold higher than that of starch medium after 7 days of culture. The product yield was 0.09 gig of consumed carbon source, which was about 3.0-fold higher than that of starch medium after 7 days of culture.