• Korean journal of food and cookery science
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• v.26 no.4
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• pp.469-474
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• 2010

In this study, we isolated two species of bacteria for the powerful biotrasnformation of ginsenosides from Kimchi and human feces. Using biochemical tests and 16s rRNA sequencing, the selected strains were identified as Latobacillusplantarum (CKDHC0801) and Lactobacillussakei (CKDHC0802). Changes in cell growth and pH were examined in red ginseng. CKDHC 0801 and CKDHC 0802 reached their maximum growth phase after 24 hr and 48 hr, respectively, whereas the combined culture of CKDHC 0801 and CKDHC 0802 showed higher cell growth than bacterial strain alone. During fermentation of CKDHC 0801 and the combined culture, the pH values decreased from 5.2 to 4.2 after 24 hr, but CKDHC 0802 reached pH of 4.2 after 3day. The identities of ginsenosides were biotransferred from high molecular (Rg1 and Rb2) to low molecular (Rg3, Rg5, Rk1, PPD) by fermentation of both bacteria. Therefore, the results of this study demonstrate that CKDHC 0801 and CKDHC 0802 could be used to enhance to effects of red ginseng.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.681-686
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• 2019

In this work, the effect of the culture medium composition on microbial growth and ethanol production in Clostridium autoethanogenum culture was investigated to enhance the ethanol productivity. D-Ca-pantothenate, vitamin B₁₂ (as vitamins), and sodium sulfide (as sulfur source) were selected as examined components, and the effects of components' concentration on cell growth and ethanol production was investigated. For D-Ca-pantothenate concentrations varing from 0.5, 5, 50 and 500 mg/L, a slight increase in the ethanol production was observed at the 0.5 mg/L, but negligible differences in microbial growth and ethanol production were measured for the concentration ranges examined. The effect of vitamin B₁₂ concentrations from 0.1, 1.0, 10, and 100 mg/L on the microbial growth and ethanol production was investigated, and it was found that the ethanol production using a 0.1 mg/L of vitamin B₁₂ concentration increased by 245% compared to that of using the basic medium concentration (10 mg/L). The effect of sodium sulfide concentrations (0.5, 5, and 10 g/L) on the microbial growth and ethanol production was also studied, and the inhibition of microbial growth was observed when the sodium sulfide usage was over 0.5 g/L. In conclusion, changes in D-Ca-pantothenate and sodium sulfide concentrations did not affect the ethanol production, whereas even a 100 times lower concentration of vitamin B₁₂ than that of the basic medium improved the production.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.183-191
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• 2010

In this study, we isolated 179 bacterial strains using benzene, phenol, ethylbenzene, aniline, cumene, toluene as growth substrate from TCE contaminated soils and wastewaters. All the 179 strains were screened for TCE (30 mg/L) removal (growth substrate 0.2 g/L, $30^{\circ}C$, pH 7, cell biomass 1.0 g/L (w/v)) under aerobic condition for 21 days. EK2 strain using aniline showed the highest removal efficiency (74.4%) for TCE degradation. This strain was identified as Delftia acidovorans as the results of API kit, 16S rDNA sequence and fatty acid assay. In the batch culture, D. acidovorans EK2 showed the bio-degradation for TCE in the various TCE concentration (10 mg/L to 200 mg/L). However, D. acidovorans EK2 did not show the bio-degradation in the TCE 250 mg/L. D. acidovorans EK2 also show the removal efficiency (99.9%) for 12 days in the low concentration (1.0 mg/L). Optimal conditions to degrade TCE 200 mg/L were cell biomass 1.0 g/L (w/v), aniline 0.5 g/L, pH 7 and $30^{\circ}C$. Removal efficiency and removal rate by D. acidovorans EK2 strain was 71.0% and 94.7 nmol/h for 21 days under optimal conditions. Conclusion, we expect that D. acidovorans EK2 may contribute on the biological treatment in the contaminated soil or industrio us wastewater.

• Microbiology and Biotechnology Letters
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• v.36 no.1
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• pp.21-27
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• 2008

As an effort to search new bacterial biocontrol agents against pepper anthracnose, we screened myxobacteria, which might inhibit the growth of Colletotrichum acutatum, the agent of that plant disease. When 93 myxobacterial strains including 59 Myxococcus spp. and 34 Corallococcus spp. were tested against C. acutatum ACYSJ001 on agar plates, 10 strains identified as the genus Myxococcus significantly obstructed the growth of C. acutatum, whereas the majority of strains belonging to the genus Corallococcus did not demonstrate any counteractive effect. Such results have indicated that the strains of the genus Myxococcus have a high potential to play roles of biocontrol agents for control of pepper anthracnose. These also have revealed that the strains of the genus Myxococcus could be used as excellent microbial resources for screening novel antifungal substances.

• KSBB Journal
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• v.9 no.3
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• pp.287-293
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• 1994

A bacterium isolated from waste coal mine water around Hawsun had an ability for the degradation of hydrogen sulfide. The isolate was identified as Thiobacillus sp. IW. on the basis of its morphological, physiological and chemotaxonomical characteristics. The optimum pH and temperature were 7 and $30^{\circ}C$, respectively. Growth occurred in a pH range of 3 to 9. Due to the sulfate accumulated in liquid medium, the pH decreased. As a consequence the cell growth was inhibited. Potasium nitrate and glutamic acid were utilized as a nitrogen source but urea and ammonium chloride not consumed. Denitrification occurred in a basal medium containing the glucose but did not in a basal medium containing the malate. The maximum specific growth rate of cell was 0.78h-1 and generation time was 0.9 hour. The cell productivity was 6.25mg/1$.$h and the isolate grew logarithmically up to 18 hour. These results indicate that the isolate can be a suitable bacterium responsible for degradation of hydrogen sulfide as malodorous compounds.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.522.1-522
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• 1986

5'-Xanthylic acid 생성균주인 Brevibacterium ammoniagenes ATCC 21263 R에 XMP에서 GMP로의 전환효소인 GMP synthetase활성을 부여하기 위해 동종간 세포융합을 시도하여 융합균주들을 얻었다. 이들 우량 융합균주들과 융합모균의 GMP synthetase 활성을 측정하여 상호 비교하였으며, pH 변화에 따른 GMP synthetase 활성과 GMP 생성량과의 관계를 검토하였다. 또한 최적 pH에서 균성장에 따른 당소모량과 GMP 생성량을 비교하였다.

• KSBB Journal
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• v.15 no.2
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• pp.174-180
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• 2000

Pichia pastoris and Hansenula polymorpha, the methylotrophic yeasts have been widely used as a host for the production of e eudaryotic proteins due to the advantages related to their inherited characters. This paper describes the method to enhance t the productivity of recombinant proteins by P. pastoris and H. po$\psi$morpha. In the production of recombinant proteins using a f fed batch fermentation system, the effects of specific growth rate on the specific expression rate of re$\infty$mbinant proteins w were studied. In both species, the expression system of recombinant proteins using the fed batch fermentation was optimezed.

• The Korean Journal of Mycology
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• v.22 no.1
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• pp.107-116
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• 1994

Interorder somatic hybrids were obtained by protoplast fusion between Pleurotus ostreatus in the order Agaricales and Elfvingia applanata in the order Aphyllophorales. The fusants were classified into stable heterokaryons and spontaneously segregated heterokaryons. Hyphae of all fusion products except two strains did not form clamp connections. Out of them, two clamped and three clampless fusants produced mature fruiting bodies by light-dark cycle on sawdust rice bran medium. All of these basidiocarps had clamp connections. Three fusants were analysed with the distribution of progenies and segregation of genetic characters by random spore analyses. The genetic markers were shown to segregate and recombine in the first generation of monospores isolated from basidiocarps. Phenotypes of a large number of auxotrophic progenies were not detected in the two clamped fusants. The aberration ratio of segregants indicated the gene interaction resulting from different genome structure between distantly related species. The polymerase chain reaction (PCR) was adopted for the detection of somatic hybrids nuclear DNA. Four fusants showed a positive results in three kinds of primers. The prominent reaction products are represented by new bands in primer # 87 and # 125. Out of four fusants, two somatic hybrids had non-parental mtDNA patterns when digested with EcoR1 and HindIII. Comparison of somatic hybrids, tissue culture isolates(TC) and multispore germination isolates(MS) were made using esterase isozyme analysis. It is apparent that somatic hybrids had a minor banding patterns which are quite different from those of parents.

• The Korean Journal of Food And Nutrition
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• v.16 no.4
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• pp.289-295
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• 2003

This is a part of study on the hydrolysis of seaweed using microorganisms. A microflora sample obtained from a decayed pine tree was purified by pure culture of 4 times. As the result, 16 isolated strains were obtained from the microflora sample and then each strain was incubated in a liquid medium with sea tangle powder for 3 weeks. Ratios of reduced sugar to total sugar of 08A211, 08C221 and 08B121 strains were highest. Accordingly, these three strains were incubated in 3 different liquid media of sodium alginate, sea tangle powder, and sea mustard powder for 3 or 4 weeks. The ratios of reduced sugar to total sugar and cell growth were measured once a week. Cell growth and ratios of reduced sugar to total sugar was highest for 08B121 in all the liquid media.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.349-354
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• 2016

A variety of nuruks collected in different areas in Korea were explored to isolate sixty yeast strains that was able to grow at 44℃. MBY/L1569 strain, which showed the highest growth rate, was selected and identified as Pichia farinosa (Millerozyma farinosa). The isolated strain exhibited superior resistance to heat, acid, and alkali compared with those of P. farinosa KCTC27412 as a control strain. The specific growth rate of P. farinosa MBY/L1569 at 46℃ was 0.37 ± 0.05 h⁻¹, and the highest specific growth rate of 0.50 ± 0.02 h⁻¹ was obtained when it was grown at pH 7.0 and 37℃ with 50 g/l (w/v) glucose as the carbon source. Under optimum growth conditions, strain MBY/L1569 produced ethanol 19.66 ± 0.68 g/l from glucose 50 g/l, with an approximate yield of 40%. P. farinosa MBY/L1569 was deposited at the Korean Collection for Type Cultures as pichia farinosa KCTC27753.