• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.4
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• pp.99-104
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• 2001

The influence of agitation speed on the yeast growth was investigated in the production of probiotic feed from pulverized liquified food wastes by aerobic fermentation. A yeast Kluyvermyces marxianus was selected through a preliminary screening. The yeast was cultured by 2liter jar fermenter. in 10% solid(w/v) substrate of liquified food waste at $35^{\circ}C$ with each different agitation speed of 500, 900 and 1200 rpm. For the acceleration of enzyme excretion mixed culture with Aspergillus oryzae was also attempted and the results were compared to those of single culture. As results the viable cell number was increased by increasing agitation speed. But it showed highest value in 900rpm and then decreased in 1200rpm. The mixed culture increased amylase activity and growth rate, but did not seem to enhance the highest viable cell count in the final fermentation stage.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.10
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• pp.1399-1406
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• 2000

A continuous culture study was conducted to determine the impact of ruminal degradable soy protein (S-RDP) level and dilution rate (D) on growth of ruminal non-structural carbohydrate-fermenting microbes. Corn starch, urea and isolated soy protein (ISP) were used to formulate three diets with S-RDP levels of 0, 35 and 70% of total dietary CP. Two Ds were 0.03 and $0.06h^{-1}$ of the fermenter volume in a single-effluent continuous culture system. As S-RDP levels increased, digestibilities of dietary dry matter (DM), organic matter (OM) and crude protein (CP) linearly (p=0.001) decreased, whereas digestion of dietary starch linearly (p=0.001) increased. Increasing D from 0.03 to $0.06h^{-1}$ resulted in decreased digestibilities of dietary DM and OM, but had no effect on digestibilities of dietary starch (p=0.77) and CP (p=0.103). Fermenter pH, the concentration of volatile fatty acids (VFA) and daily VFA production were unaffected (p=0.159-0.517) by S-RDP levels. Molar percentages of acetate, propionate and butyrate were greatly affected by S-RDP levels (p=0.016-0.091), but unaffected by D (p=0.331-0.442). With increasing S-RDP levels and D, daily bacterial counts, daily microbial N production (DMNP) and microbial efficiency (MOEFF; grams of microbial N produced per kilogram of OM truly digested) were enhanced (p=0.001). The increased microbial efficiency with increasing S-RDP levels is probably the result of peptides or amino acids that served as a stimulus for optimal protein synthesis. The quantity of ruminal degradable protein from soy proteins required for optimum protein synthesis of non-structural carbohydrate-fermenting microbes appears to be equivalent to 9.5% of dietary fermented OM.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.13-19
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• 1995

In order to produce phenylalanine without tyrosine co-production, we constructed various temperature-controllable expression vectors by insertion of lower expression of the tyrA gene into the plasmid pSY130-14. And tyrosine revertant to cultivate without addition of tyrosine, was selected from Escherichia coli strain AT2471[tyrA , thi ] by spontaneous mutation. The strain AT2471 harbouring plasmid pSY146A and the tyrosine revertant 5 harbouring plasmid pSY111-14 produced 12 g/l and 15 g/l of phenylalanine respectively in a 2.5 l jar fermenter at a constant temperature of $39^{\circ}C$ after 55 hours cultivation.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.25-29
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• 1974

1. Penicillium sp. C 13-13 strain was obtained with the treatment of mutagenic agents(N.T.G.) and by single spore isolation method from the Penicillium sp. C8-14 strain, which was reported in the previous paper. 2. The above strain had a few spores and to obtain seed culture, it was cultured at $30^{\circ}C$ and initial pH $4.5{\sim}5.0$, with air rate 6l/min., and agitation 600 rpm for 48 hours in 10% wheat bran medium in 20l- Jar fermenter. When the broth that had above 70ml of mycelium was inoculated into wheat bran medium and incubated at $29{\sim}33^{\circ}C$ for 72 hrs, the cellulase activity of the koji was higher. 3. Adding calcium chloride and magnecium sulfate to the wheat bran medium to 1.5% and 0.015% respectively, the cellulase activity of the koji was higher than that of the control.

• Korean Chemical Engineering Research
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• v.47 no.4
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• pp.506-511
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• 2009

In order to improve the bacterial cellulose(BC) production yield, centrifugal and inclined centrifugal impellers were developed. A 6 flat-blade turbine impeller was used as a control system. The flow pattern in the fermenter and volumetric oxygen transfer coefficient($k_La$) of these fermentation systems were studied. Fermentations were carried out for the production of BC by G. hansenii PJK in a 2-L jar fermenter equipped with new impellers. Liquid medium was circulated from the bottom, through the cylinder of the impeller and to the wall. The volumetric oxygen transfer coefficients, $k_La$, of inclined centrifugal and centrifugal impeller systems at 100 rpm were 23 and 15% of the conventional turbine impeller system, respectively. However, the conversion of microbial cells to cellulose non-producing mutant decreased and this results in the increase in BC production at low rotating speed of impellers.

• KSBB Journal
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• v.19 no.1
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• pp.78-82
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• 2004

Experiments were carried out to select an organic nitrogen source and optimize the culture conditions for the production of arachidonic acid by Mortierella alpina DSA-12. Corn steep powder(CSP) was selected as an organic nitrogen source based on arachidonic acid production and raw material price. The optimum C/N ratio was in the range of 15 to 17 with the medium containing glucose as carbon source and CSP as nitrogen source. The optimum culture conditions for arachidonic acid production showed 500 rpm agitation and 25$^{\circ}C$ culture temperature at 0.5 vvm aeration. Under the optimum conditions, the concentration of cell, total lipid and arachidonic acid were 21.8 g/L, 10.2 g/L and 3.70 g/L, respectively, from 50 g/L glucose and 18 g/L CSP. In the 500 L fermenter with 0.5 vvm aeration and 200 rpm agitation, the concentration of cell, total lipid and arachidonic acid were 19.8 g/L, 9.1 g/L and 3.67 g/L, respectively, from 50 g/L glucose and 18 g/L CSP. This result showed that an arachidonic acid production could be possible with a bench-scale fermenter using corn steep powder as a nitrogen source.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.3
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• pp.126-131
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• 2002

For the probiotic feed production from residual food waste, aerobic liquid fermentation was conducted by thermophilic bacteria. 11 Strains of bacteria were isolated from several soil sources and residual food waste. Screening was carried by shaking incubator for the separation of thermophilic strain at $55^{\circ}C$. The isolated strains were tested for enzyme activities such as ${\alpha}$-amylase and protease. 6 Bacterial strains were chosen and were adapted by repeated fermentation processes in food waste substrate. The viable cell count of them at final fermentation stages were shown as $3-7{\times}10^9/ml$ in 2L-jar fermenter. Among them B3, B6 showed higher enzyme activity. By the mixed fermentation of B3, B6 and Bacillus stearothermophilus, the highest viable cell count reached to $1.4{\times}10^{10}/ml$ in 8 hours.

• 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.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.84-86
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• 2014

Mass production of biocontrol agent is an essential step for its commercial use. Media composition and culture conditions for production of Bacillus amyloliquefaciens SKU-78, a potential biocontrol agent against bacterial wilts, were optimized by a flask culture. Low cost media combining nitrogen and carbon sources were tested. Maximum cell growth (> $2{\times}10^9$ CFU/ml) was obtained in a medium of 5% soy flour combined with 3% corn starch after 24 h cultivation. The optimum initial pH, temperature and shaking speed was 5.5, $30^{\circ}C$ and 150-250 rpm, respectively. Fermentation of SKU-78 was scaled up in 30 L fermenter and the profiles of cell density, pH, dissolved oxygen and spore formation were recorded. After 8 h lag phase, exponential growth occurred and reached at maximum viable cell number ($1.2{\times}10^{11}$ CFU/ml) after 20 h. The SKU-78 strain grown in a low cost medium exhibited the high suppression of bacterial wilts. The results indicate that SKU-78 strain can be produced in a low cost medium and provide a basis for scaling up to industrial level.

• KSBB Journal
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• v.31 no.2
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• pp.105-112
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• 2016

Ferritin is known to regulate iron metabolism and maintain iron in a variety of the eukaryotic organisms. The region encoding the mature ferritin (0.47 kb, H-type) of Periserrula leucophryna was amplified using the designed primers including restriction enzyme site and termination codon and subcloned in frame to the pRBAS secretion vector containing the signal sequence, RBS, and promoter of amylase gene (E. coli-Bacillus shuttle vector), resulting in recombinant pRBAS-PLF vector. Recombinant ferritin (18 kDa) was correctly processed and secreted from Bacillus subtilis LKS strain harboring the pRBAS-PLF vector and quantitatively analyzed by SDS-PAGE and western blot, respectively. Secretion of the ferritin was optimized by culture conditions (host, medium, temperature, nitrogen source) in 3 L batch culture and 5 L jar fermenter. Finally. the ferritin was largely produced using 50 L fermenter as the following conditions; at $30^{\circ}C$, 150 rpm, 1 vvm in Bacillus subtilis LKS using PY medium. The secreted ferritin was maximally measured (approximately 177.6 ug/ml) when the cell density reached to 14.4 at $OD_{600}$ (20 h incubation). The iron binding activity was confirmed by Perls' staining in 7.5% non-denaturing gel, indicating that the multimeric ferritin (composed of 24 subunits) was formed in the culture broth after secretion. Biologically, the culture broth and powder type containing ferritin were tested for possibility as feed additive in chicken broiler. As a result, the ferritin stimulated the growth of chick broil and improved feed efficiency and production index.