• Journal of Life Science
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• v.15 no.1 s.68
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• pp.15-20
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• 2005

The unstructured model was tested to describe mycelial growth, exopolysaccharide formation, and substrate consumption in submerged mycelial culture of Paeeiliomyees tenuipes C240. The Logistic equation for mycelial growth, the Luedeking-Piret equation for exopolysaccharide formation, and Luedeking­Piret-like equations for glucose consumptions were successfully incorporated into the model. The value of the key kinetic constants were: maximum specific growth rate ${\mu}m,\;0.7281\;h^{-1};$ growth­associated constant for exopolysaccharide production $(\alpha),\;0.1743g(g\;cells)^{-1}$; non-growth associated constant for exopolysaccharide production $(\beta),\;0.0019g(g\;cells)^{-1}\;;$ maintenance coefficient $(m_s),\;0.0572g\;(g\;cells)^{-1}$. When compared with batch experimental data, the model successfully provided a reasonable description for each parameter during the entire growth phase. The model showed that the production of exopolysaccharide in P. tenuipes C240 was growth-associated. The model tested in the present study can be applied to the design, scale-up, and control of fermentation process for other kinds of basidiomycetes or ascomycetes.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.4
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• pp.147-152
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• 2000

For the probiotic feed production from residual food waste by using the yeast Kluyveromyces marxianus, aerobic liquid fermentation was attempted at $35^{\circ}C$. After grinding finely, optimal fermentation conditions of the substrate was investigated in shaking incubator. By controlling water content yeast growth was studied at each different solid content of 5, 10 and 15% respectively. The most active growth of the yeast was shown at 10%. For the stimulation of the cell growth, mixed culture with Aspersillus oryzae was conducted in a 2 litre-jar fermenter. As the results, the yeast growth rate was increased, but the maximum viable cell count amounted was slightly higher as $3.5{\times}10^9/ml$ than single culture.

• Journal of Microbiology and Biotechnology
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• v.18 no.12
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• pp.1938-1944
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• 2008

The procpb gene encoding human procarboxypeptidase B (proCPB, GeneBank access code AJ224866) was cloned and its Pichia expression plasmid, $pPIC9{\alpha}$/hproCPB (9.2 kb), was constructed, in which procpb was under the control of the AOXl promoter and connected to the downstream of the mating factor ${\alpha}$-1 ($MF{\alpha}1$) signal sequence. The plasmid was linearized by digestion with Sacl, and integrated into the genome of P. pastoris strain GS115. By culturing of Pichia transformant on methanol medium, the human proCPB was successfully expressed and secreted into the culture supernatant. Moreover, Western blot analysis of the extracellular proteins showed proCPB bands clearly at a molecular mass of 45 kDa, confirming the expression of proCPB with its right size. The CPB activity reached about 3.5 U/ml and 12.7 U/ml in the flask and fermentor batch cultures of Pichia transformant, respectively. No CPB enzyme activity was found in the intracellular fraction. When the fed-batch cultivation was performed with methanol and glycerol mixture as a feeding medium, the extracellular CPB activity was increased to 42.0 U/ml, which corresponds to a 3.3-fold higher level of CPB activity than that of batch culture. The $K_m$ and $k_{cat}$ values of recombinant human CPB enzyme for hippuryl-$_L$-Arg as a substrate were estimated to be 0.16 mM and $11.93\;sec^{-1}$, respectively.

• Journal of the Korean Society of Food Culture
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• v.14 no.1
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• pp.21-28
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• 1999

This study was conducted to investigate the antioxidant and synergistic effects upon different concentration(0.02, 0.1, 1%) of tryptophan and arginine of soybean oil during incubation at $60^{\circ}C$. Peroxide value(POV), acid value(AV) and thiobarbituric acid(TBA) value of each oil were monitored. Tryptophan and arginine showed antioxidative effects in all concentration. In case of incubating antioxidative effect of tryptophan was similar to that of TBHQ that of arginine was considerably higher than that of ${\alpha}-tocopherol$, but was lower than that of tryptophan. Synergistic effects among tryptophan, arginine and some food antioxidant were shown to be available in all substrates and the best effect was shown in substrate added compound of tryptophan and ${\alpha}-tocopherol$.

• Korean Journal of Microbiology
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• v.44 no.2
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• pp.156-163
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• 2008

In this study, we isolated 32 strains of kerosene degrading bacteria from oil contaminated soil by enrichment culture. Isolates were screened for kerosene degradation efficiencies and K14 were selected which had the highest removal efficiency for 1,000 mg/L of kerosene. K14 were identified as Pseudomonas aeruginosa by morphological, biochemical test and 16S rDNA analysis. The optimal culture condition were determined as initial inoculated cell concentration, 1.0 g/L; substrate concentration, 1,000 mg/L; temperature $30^{\circ}C$; pH 7. When we enforced batch test in this condition, K14 degraded 72% of kerosene with 1,000 mg/L during 72 hr. And, at low concentration (200 mg/L), K14 degraded 95.8% of kerosene during 48 hr. As a result, kerosene biodegradation by Pseudomonas aeruginosa K14 could be useful for clean up of groundwater and soil contaminated with crude oil.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.160-165
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• 2003

This study was carried out to investigate the effect of several substrates; used rockwool, several spent mushroom composts, and common used media, such as rockwool and vermiculite, on growth and fruit quality of cucumber. Cucumber grew dramatically in the rockwool+peatmoss (1:2 v/v) (RP) and fine granular rockwool in hydroponic system using Yamaztiki's solution for cucumbers. The yield of cucumber fruit was highest in recycled winter mushroom compost (RW), and followed by 100% perlite (Par), recycled oyster mushroom compost (RO), and RR but there was no significant difference among these three media. Soluble solid and firmness were higher in Per and vermiculite (Ver), and any difference was not found among the others. Vitamin C was not influenced by kind of substrate. The results confirm that several reused or recycled substrates have high possibilities for use as medium for hydroponic culture in cucumber.

• Journal of Life Science
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• v.14 no.2
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• pp.320-324
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• 2004

The objective of this study was investigate the characteristic of biosurfactant produced from the isolated strain. The strain was isolated from soil samples and identified as Bacillus sp. TBM 911-5 by physiological characteristics and the partial nucleotide sequence analysis of 16S rDNA. We measured the surface tension every 6 hours for 80 hours. The surface tension of the culture filtrate of Bacillus sp. TBM 911-5 was decreased to 29 mN/m. Biosurfactant concentration was determined by diluting the culture filtrate until the critical micelle concentration (CMC). The biosurfactant emulsified hydrocarbons, vegetable oil and crude oil. Using soybean oil as substrate, the maximum emulsification activity and stability was obtained from the biosurfactant. The biosurfactant produced from Bacillus sp. TBM 911-5 had strong properties as an emulsifying agent and an emulsion-stabilizing agent.

• Mycobiology
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• v.42 no.4
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• pp.368-375
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• 2014

Red ginseng (Panax ginseng), a Korean traditional medicinal plant, contains a variety of ginsenosides as major functional components. It is necessary to remove sugar moieties from the major ginsenosides, which have a lower absorption rate into the intestine, to obtain the aglycone form. To screen for microorganisms showing bioconversion activity for ginsenosides from red ginseng, 50 yeast strains were isolated from Korean traditional meju (a starter culture made with soybean and wheat flour for the fermentation of soybean paste). Twenty strains in which a black zone formed around the colony on esculin-yeast malt agar plates were screened first, and among them 5 strains having high ${\beta}$-glucosidase activity on p-nitrophenyl-${\beta}$-D-glucopyranoside as a substrate were then selected. Strain JNO301 was finally chosen as a bioconverting strain in this study on the basis of its high bioconversion activity for red ginseng extract as determined by thin-layer chromatography (TLC) analysis. The selected bioconversion strain was identified as Candida allociferrii JNO301 based on the nucleotide sequence analysis of the 18S rRNA gene. The optimum temperature and pH for the cell growth were $20{\sim}30^{\circ}C$ and pH 5~8, respectively. TLC analysis confirmed that C. allociferrii JNO301 converted ginsenoside Rb1 into Rd and then into F2, Rb2 into compound O, Rc into compound Mc1, and Rf into Rh1. Quantitative analysis using high-performance liquid chromatography showed that bioconversion of red ginseng extract resulted in an increase of 2.73, 3.32, 33.87, 16, and 5.48 fold in the concentration of Rd, F2, compound O, compound Mc1, and Rh1, respectively.

• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.242-247
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• 1991

- Since steroid $\Delta^1$-dehydrogenase synthesis has been known to be inducible, the mechanism of the enzyme induction of Arthrobacter simplex IAM 1660 was investigated. Among various steroids tested for inducers, hydrocortisone was the most effective inducer when hydrocortisone was used as a substrate for steroid $\Delta^1$-dehydrogenase. Steroid $\Delta^1$-dehydrogenase synthesis was effectively induced by progesterone, prednisolone and androstenedione, while the enzyme was less induced by cholesterol and not by phytosterols. The results suggest that the presence of 3-keto group and short side chain of steroids are the favorable factors for the induction of the $\Delta^1$-dehydrogenase synthesis. The enzyme was induced at the highest level when hydrocortisone was added at early log phase to the concentration of 0.01% of the culture and the culture was grown for 15 hours.

• Korean Journal of Microbiology
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• v.17 no.1
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• pp.42-48
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• 1979

Cellulases were isolated from both healthyl(PC) and virus0infected penicillum chrysogenum(PCV) in the wheat bean culture, and some properties of the enzymes were studied. 1) At $37^{\circ}C$, pH 6, 4 and 6day's culture the maximal enzyme yield was obtained in both PC and PCV. 2) The optimum temperature for the PC cellulase was at $50^{\circ}C$, and that for the PCV enzyme was the same. 3) The optimum pH for the PC enzyme was at 5.0, whereas the PCV enzyme was at 6.0, indicating that they are isozymes. 4) When Na-CMC was used as a substrate, PC enzyme was twice as high as the activity of PCV enzyme.