• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.3
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• pp.167-172
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• 2001

Staphylokinase (SAK) was produced in B. subtilis using two different promoter systems, i.e. the P43 and sacB promoters. To maximize SAK expression in B. subtilis, fermentation control strategies for each promoter were examined. SAK, under P43, a vegetative promoter transcribed mainly by $\sigma$(sup)B containing RNA polymerase, was overexpressed at low dissolved oxygen (D.O.) levels, suggesting that the sigB operon is somewhat affected by the energy charge of the cells. The expression of SAK at the 10% D.O. level was three times higher than that at the 50% D.O. level. In the case of sacB, a sucrose-inducible promoter, sucrose feeding was used to control the induction period and induction strength. Since sucrose is hydrolyzed by two sucrose hydrolyzing enzymes in the cell and culture broth, the control strategy was based on replenishing the loss of sucrose in the culture. With continuous feeding of sucrose, WB700 (pSAKBQ), which contains the SAK gene under sacB promoter, yielded ca. 35% more SAK than the batch culture. These results present efficient promoter-dependent control strategies in B. subtilis host system for foreign protein expression.

• Journal of Microbiology and Biotechnology
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• v.28 no.10
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• pp.1706-1715
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• 2018

Several non-methylotrophic bacteria have been reported to improve the growth and activity of methanotrophs; however, their interactions remain to be elucidated. We investigated the interaction between Methylocystis sp. M6 and Microbacterium sp. NM2. A batch co-culture experiment showed that NM2 markedly increased the biomass and methane removal of M6. qPCR analysis revealed that NM2 enhanced both the growth and methane-monooxygenase gene expression of M6. A fed-batch experiment showed that co-culture was more efficient in removing methane than M6 alone (28.4 vs. $18.8{\mu}mol{\cdot}l^{-1}{\cdot}d^{-1}$), although the biomass levels were similar. A starvation experiment for 21 days showed that M6 population remained stable while NM2 population decreased by 66% in co-culture, but the results were opposite in pure cultures, indicating that M6 may cross-feed growth substrates from NM2. These results indicate that M6 apparently had no negative effect on NM2 when M6 actively proliferated with methane. Interestingly, a batch experiment involving a dialysis membrane indicates that physical proximity between NM2 and M6 is required for such biomass and methane removal enhancement. Collectively, the observed interaction is beneficial to the methanotroph but adversely affects the non-methylotroph; moreover, it requires physical proximity, suggesting a tight association between methanotrophs and non-methylotrophs in natural environments.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.327-332
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• 1994

Optimum conditions for the production of acetoin and ammonia as the precursors of tetramethylpyrazine(TMP) were determined using Lactococcus lactis subsp. lactis biovar. diacetylactis FC1 in a modified Lactose-citrate broth containing galactose, citrate, and arginine. The cell growth and the productivity of acetoin and ammonia were remarkably increased in an aerobic culture with 10 $\mu M$ of hematin. For the optimum conditions of acetoin and ammonia production, the concentration of citrate and arginine were adjusted to 156 mM and 50 mM after 18 hr cultivation, and citrate and galactose to 156 mM and 50 mM after 36 hr cultivation, respectively. In these conditions, acetoin and ammonia were produced to the final concentration of 127 mM and 195 mM, which were the highest concentations, respectively. The optimum conditions of the TMP production were also determined as follows; 4 hours at 121, pH 8.3, and the maximal yield of TMP under these conditions was 0.81 g/l.

• The Korean Journal of Mycology
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• v.21 no.2
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• pp.112-119
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• 1993

Various microorganisms secreting plant growth regulators were screened from the 100 microbial isolates including bacteria, actinomycetes and fungi. The isolates showing distict influence on the plant growth were identified as Aspergillus niger. The germinations of Raphanus and Cucubis seeds were completely inhibited by the culture filtrates of A. niger KK, A. niger KKS and A. niger ATCC 9462. The culture filtrates of the three strains also inhibited the formation and development of roots and hypocotyls of Raphanus. The culture filtrates of A. niger ATCC 26550 induced the hypocotyl curvature of Raphanus like plant hormone-auxin and at the same time caused the necrosis of the whole leaves.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.2
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• pp.155-160
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• 2003

The optimum cultural conditions for production of red pigment from Monascus anka KCTC 6121 on solid culture were studied. The optimal conditions were found that the strain was cultivated on polished rice with 25% initial moisture content, at 3$0^{\circ}C$, 90% humidity for 12 days. It was also found that the maximum red pigment was extracted when the final culture was left in 80% ethanol for 2 days. The light stability of the extracted red pigment was relative stable since the discoloration rate was less than 8% in 30 days under the indirect light.

• Journal of Animal Science and Technology
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• v.49 no.3
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• pp.359-368
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• 2007

Holstein cows(n=12) were assigned to one of three diets containing control diet and diets containing a microbial culture, 50ml(T1) and 100ml(T2) SDN(R)(amicrobial culture), per day. The basal diet containing concentrate mixture, corn silage and timothy hay were fed midlactating cows for 12 weeks. Milk production tended to be higher for cows fed T2 diet (20.8kg/day) than fed T1(19.7kg/d) and control diet (19.2kg/day).  There was a tendency of an increase in 4% FCM for cows fed T2 diet(19.6kg/day) than T1(18.8kg/d) and control diet(18.4kg/day). Milk components were not found to be different between cows fed control diet and SDN(R) diets. There was a tendency an increase in milk protein for cows fed control diet(3.43%) compared with microbial diets, T1 and T2(3.08% and 3.20%). However, milk protein production was not significantly different between control diet(0.65kg/d) and T1(0.61kg/d) or T2(0.67kg/d). Somatic cell counts for cows fed T1(72,000) and T2(60,000/ml) were lower than cows fed control diet (108,000/ml) (P<0.05). In conclusion, the cows that were fed diets containing SDN(R) as a microbial culture resulted a tendency of an increase in milk production and a reduction of somatic cell counts which indicates improved milk quality and hygiene.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.46-52
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• 2014

This study was conducted to compare colony forming unit (CFU) of microorganisms in closed and open soilless culture systems for estimating the possibility for potential disease occurrence. Samples were collected at four different positions in four commercial greenhouses with closed or open soilless culture system using rock wool or coir as substrate, respectively. The distance between sampling positions was 3 cm starting from the substrate and the surface area of each position was $25cm^2$. The CFU of fungi was significantly higher in the open system, while that of bacteria was not significantly different but showed relatively lower in the closed system. Samples collected at the plastic surface of the substrates where little environmental effects occurred from drainage showed lower CFU than any other positions. The principal component analysis showed that samples collected on the drainage pathway highly affected the changes in microbial population in the greenhouse. These results indicated that greenhouses with closed soilless culture are expected to have more advantageous conditions for restraining the microbial growth, resulting in the lower potential of disease occurence in greenhouse ecosystem.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2006.11a
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• pp.127-130
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• 2006

Coenzyme Q10(CoQ10) is a biological quinine compound that is widely found in living organisms including yeast, plants, and animals. CoQ10 has two major physiological activities:(a)mitochondrial electron-transport activity and (b )antioxidant activity. Various clinical applications are also available: Parkinson's disease, Heart disease, diabetes. Because of its various application filed, the market size of CoQ10 is continuously expanding all over the world. A Japanese company, Nisshin Pharma Inc. is the first industrial producer of CoQ10(1974). CoQ10 can be produced by fermentation and chemical synthesis. In several companies, these two methods are used for the production of CoQ10:chemical synthesis - Yungjin, Daewoong, Nishin Parma; fermentation - Kaneka, Kyowa, Yungjin, etc. Researchs in microbial production of CoQ10 have several steps: screening of producing microorganisms, strain development, fermentation process, purification process, scale-up process, plant production. Several strategies are available for the strain development : Random mutation and screening, directed metabolic engineering. For the optimization of fermentation process, various conditions (nutrient, aeration, temperature, culture type, etc.) are considered. Purification is one of the most important step because the quality of final products entirely depends on its purity. The production cost will be reduced and the quality of the CoQ10 will be impoved by continuous researches in strain development, fermentation process, purification process.

• The Korean Journal of Mycology
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• v.25 no.2 s.81
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• pp.85-90
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• 1997

The Isozyme activities of Lentinula edodes were studied as a preliminary study for genetic analysis after protoplast fusion. The presence of peroxidase, esterase, superoxide dismutase, acid phosphatase, alkaline phosphatase, alcohol dehydrogenase and ${\alpha}-amylase$ was examined. An intracellular buffer-soluble protein from the mycelia was used for enzyme analysis on nondenaturing polyacrylamide gels. The auxotrophs of Lentinula edodes were positive for peroxidase, esterase, superoxide dismutase and acid phosphatase. However, alkaline phosphatase, alcohol dehydrogenase and ${\alpha}-amylase$ were not detected. The esterase and peroxidase were not affected by the various culture age. Isozyme identification may be a useful tool after protoplast fusion.

• Journal of Microbiology and Biotechnology
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• v.26 no.1
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• pp.120-129
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• 2016

An industrial complex in Wonju, contaminated with trichloroethene (TCE), was one of the most problematic sites in Korea. Despite repeated remedial trials for decades, chlorinated ethenes remained as sources of down-gradient groundwater contamination. Recent efforts were being made to remove the contaminants of the area, but knowledge of the indigenous microbial communities and their dechlorination abilities were unknown. Thus, the objectives of the present study were (i) to evaluate the dechlorination abilities of indigenous microbes at the contaminated site, (ii) to characterize which microbes and reductive dehalogenase genes were responsible for the dechlorination reactions, and (iii) to develop a PCE-to-ethene dechlorinating microbial consortium. An enrichment culture that dechlorinates PCE to ethene was obtained from Wonju stream, nearby a trichloroethene (TCE)-contaminated industrial complex. The community profiling revealed that known organohalide-respiring microbes, such as Geobacter, Desulfuromonas, and Dehalococcoides grew during the incubation with chlorinated ethenes. Although Chloroflexi populations (i.e., Longilinea and Bellilinea) were the most enriched in the sediment microcosms, those were not found in the transfer cultures. Based upon the results from pyrosequencing of 16S rRNA gene amplicons and qPCR using TaqMan chemistry, close relatives of Dehalococcoides mccartyi strains FL2 and GT seemed to be dominant and responsible for the complete detoxification of chlorinated ethenes in the transfer cultures. This study also demonstrated that the contaminated site harbors indigenous microbes that can convert PCE to ethene, and the developed consortium can be an important resource for future bioremediation efforts.