• KSBB Journal
• /
• 제13권6호
• /
• pp.730-734
• /
• 1998

An이ew식과 Aiba삭을 조합하여 에탄올 생산단주인 Saccharomyces cerevisiae ATCC 24858의 비성장속도를 당농도와 에탄올 농도의 함수로 표현하였다. 기침의 저해영향을 받지 않는 최대 당농도 $S_m$은 150 g/L이며 기질의 저해영향은 기질농도 S와 $S-S_{max}$항의 함수로 표현되었다. 최대 비성장 속도 ${\mu}max 는 0.49 hr^{-1}, Monod상수 K_s$는 19 g/L, Andrew식의 기질저해상수 $K_1$는 139 g/L이였다. 또한 비성장속도에 영향을 마치지 앓는 최대알콜농도 Pm이 존재하였으며 그 값은 2 g/L 이였다. 따라서 Aiba식에서 비성장속도에 영향을 미치는 에탄올 농도항은 P-Pm으보 표현되었다. 본 연구의 알코올생산균주에 대한 비성장속도의 완성된 수식은 디음과 같으며 이 수식에 위한 계산값은 평균오차 6% 내외의 범위에서 실험값과 일치하였다.

• Journal of Pharmaceutical Investigation
• /
• 제28권3호
• /
• pp.151-158
• /
• 1998

The inhibition rate of bacteria growth per molecular weight was higher according as the molecular weight increased, the rate was the highest at the molecular weight 200,000. Microcapsule of ionized calcium was able to be produced by molecular weight 15,000, 30,000, 50,000 and 200,000 of chitosan which was dried for 48 hours after melting it in 2% of acetic acid, adding ionized calcium and controlling pH 1.2. The size of ionized calcium microcapsule was between 200 and $300\;{\mu}m$, the solvency, concentration and the content showed big difference by the molecular weight of chitosan. The inhibition rate of bacteria growth of microcapsule designated high in Gram positive, which was high in S. aureus, S. epidermidis and Bacillus subtilis, low in S. mutans, high in C. albicans in fungi, low in A. niger. The inhibition rate of bacteria growth of chitosan was comparatively high in Gram positive, low in S. mutans and it showed high numerical value in C. albicans of fungi. The rate recorded good result at molecular weight 200,000 relatively, there was no difference according to the molecular weight. The inhibition rate of bacteria growth according to the concentration of the microcapsule increased differently between $1.000{\sim}10,000\;{\mu}g/ml$, it showed antibacterial activity close to the inhibition rate of growth of chitosan rather than ionized calcium. The minimum inhibitory concentration marked the highest in the mixture of chitosan and ionized calcium for all kind of bacteria generally, there was a little difference between yeast and fungi.

• Journal of Microbiology and Biotechnology
• /
• 제13권3호
• /
• pp.332-337
• /
• 2003

Enzyme kinetics data play a vital role in the design of reactors and control of processes. In the present study, kinetic studies on pectinases were carried out. Partially purified polymethylgalacturonase (PMG) and polygalacturonase (PG) were the two pectinases studied. The plot of initial rate vs. initial substrate concentration did not follow the conventional Michaelis-Menten kinetics, but substrate inhibition was observed. For PMG, maximum rate was attained at an initial pectin concentration of 3 g/l, whereas maximum rate was attained when the initial substrate concentration of 2.5 g/l of polygalacturonic acid for PG I and PG II. The kinetic data were fitted to five different kinetic models to explain the substrate inhibition effect. Among the five models tested, the combined mechanism of protective diffusion limitation of both high and inhibitory substrate concentrations (semi-empirical model) explained the inhibition data with 96-99% confidence interval.

• 한국환경과학회지
• /
• 제31권2호
• /
• pp.141-148
• /
• 2022

In this study, the inhibition of ammonia on anaerobic digestion of butyric acid was evaluated and the potential alleviating effects of such ammonia inhibition by the addition of magnetite particles were investigated. Independent anaerobic batch tests fed with butyric acid as a sole organic source were conducted in twenty 60-mL glass bottles with 10 different treatment conditions, comprising ammonia: 0.5, 2.0, 4.0, 6.0, and 7.0 g total ammonia nitrogen (TAN)/L and magnetite particles: 0 mM and 20 mM. The increase in ammonia concentration did not cause significant inhibition on methane yield; however, a significant inhibition on lag time and specific methane production rate was observed. The IC₅₀ in the control treatments (without magnetite addition) was estimated as 6.2654 g TAN/L. A similar inhibition trend was observed in magnetite-added treatments; however, the inhibition effect by ammonia was significantly alleviated in lag time and specific methane production rate when compared to those in the control treatments. The lag time was shortened by 1.6-46.3%, specific methane production rate was improved by 6.0-69.0%. In the magnetite-added treatments, IC₅₀ was estimated as 8.5361 g TAN/L. This study successfully demonstrated the potential of magnetite particles as an enhancer in anaerobic digestion of butyric acid under conditions of ammonia stress.

• 한국미생물·생명공학회지
• /
• 제25권4호
• /
• pp.391-395
• /
• 1997

It was proved that both ethanol extracts from Mori Folium from Kangwon do and silk worm had higher inhibition acitivity on $\alpha$-glucohydrolase than the water extracts. In adding above 8.5 (mg/L) of silkworm extracts, the inhibition rate on $\alpha$-1,4 glucosidase was saturated while the inhibition rate was continuously increased in adding the extracts from Moli Folium. It was also found that the diethyl ether fraction showed much better inhibition activity than water fraction from ethanol extracts, yielding ca. 85% of inhibition rate for the extract of Moli Folium, compared to 91% for a commercially available hypoglycemic drug, Chloropropamide. In separating the diethyl ether fractions by Consecutive Sephadex gel filtration and Thin layer chromatography, three and four active spots were obtained from Moli Folium and silkworm, respectively. It is interesting that the similar Rf spots from both species among several spots in TLC have the highest inhibition acitivity on a target enzyme, which can imply that the active substances from both species are same or similar molecular weight and structure. Glucose-lowering activities of both speciese were also examined in vivo, showing that the fraction from Moli Folium had better activity than that from silkworm, and its activity was similar to that of a commercial drug.

• 미생물학회지
• /
• 제35권4호
• /
• pp.253-257
• /
• 1999

Cadaverine, putrescine, spermidine과 spermine이 spectinomycin에 의한 T4 파지 thymidylate synthase 유전자(td) intron의 splicing 억제에 미치는 영향을 조사하였다. Polyamine이 존재하지 않는 상태에서 7mM spectinomycin은 splicing rate를 약 40% 감소시켰다. 사용한 농도 범위(0.1~5mM)에서 cadaverine은 splicing rate를 감소시켰으나, putrescine은 0.5mM 농도에서 약 13% 정도의 splicing rate를 증가시켰다. Spermidine은 0.5mM 농도에서 약 11% 정도의 splicing rate를 증가시켰으며, sperimine은 0.01mM 농도에서 약 16% 정도의 splicing rate을 증가시켰다. 시험한 polyamine 중에서 특히 sperimine은 가장 낮은 농도에서 spectinomycin에 의한 억제반응을 극복하는 최고의 활성효과를 나타냈다. 이와 같은 억제 회복 효과는 polyamine에 의한 td intron 리보자임의 구조적 안정성에 기인하는 것으로 추정된다.

• 한국물환경학회지
• /
• 제33권1호
• /
• pp.8-14
• /
• 2017

Microcystis aeruginosa (M. aeruginosa) is a cyanobacterium species that can form harmful algal blooms in freshwater bodies worldwide. The use of pine needle extract (PNE) to control nuisance algae by allelopathic inhibition will be environmentally friendly and promising. PNE removed successfully upto 98% of M. aeruginosa at the following optimal conditions: pH 7, $25^{\circ}C$ of temperature, 100 rpm of mixing rate, 5 min of mixing time. These results was indicated that the amount of 1 g/L PNE was removed 1g dryweight/L of M. aeruginosa. The kinetic data showed substrate inhibition kinetics and maximum growth rate was obtained when the M. aeruginosa was grown in medium containing 0.5 g/L of initial concentration of PNE. Different substrate inhibition models were fitted to the kinetic data and found the Luong model was best. The model predicted kinetic parameters were in agreement with the experimental findings. The natural extract, PNE, can be a promising inhibition due to its high efficiency and low dose requirements.

• 한국식품영양학회:학술대회논문집
• /
• 한국식품영양학회 2003년도 하계 학술 심포지엄
• /
• pp.77-77
• /
• 2003

This study was performed to investigate the antioxidative effect as the inhibition of MDA and BSA conjugation reaction, inhibition of lipid peroxidation and the scavenging effect on DPPH radical, and antimutagenic capacities as the Ames test in 7 common vegetables taken by Korean for suggestion of prevention and dietetic treatment of chronic diseases and development of antioxidative and antimutagenic functional food. The water extracted fractions of perilla leaves were most effective in the inhibition of MDA and BSA conjugation reaction showing 77.2% of inhibition rate among 7 vegetables. The inhibition rates of ethanol extracted fractions of sedum and wild water dropwort on the lipid peroxidation were 67.1% and 61.5%, respectively. The ethanol extracted fractions of crown daisy and wild water dropwort showed the most effective results among 7 vegetables in the DPPH radical scavenging capacities showing inhibition rate of 78.8% and 73.6%, respectively. The indirect and direct antimutagenic effects of ethanol extract of 7 vegetables were examined by Ames test using Salmonella typimurium TA98 and TA100. Inhibitory effects of wild water dropwort was superior to the other vegetables on the Ames test. These results suggest that common 7 vegetables taken by Korean are believed to be a possible antioxidative and antimutagenic capacities, although the resultswere different, some or less, according to the assay method and vegetables used.

• 상하수도학회지
• /
• 제28권1호
• /
• pp.47-54
• /
• 2014

Nanotechnology has become one of the fastest developing technologies and recently applied to a variety of industries. Thus, increasing number of nano materials including various nanoparticles would be discharged into wastewater and consequently entering a biological wastewater treatment process. However, the impact of the nano particles on biological wastewater treatment has not been estimated intensively. In this research, we investigated the effect of silica nanoparticle on the oxygen uptake rates (OURs) of activated sludge used in a conventional wastewater treatment process. The inhibition (%) values were estimated from the results of OURs experiments for the silica nanoparticles with various sizes of 10-15, 45-50, and 70-100 nm and concentrations of 50, 250, and 500 ppm. As results, the inhibition value was increased as the size of silica nano particles decreased and the injected concentration increased. The maximum inhibition value was investigated as 37.4 % for the silica nanoparticles with the size of 45-50 nm and concentration of 50 ppm. Additionally, the effect of size and concentration on the inhibition should be considered cautiously in case that the aggregation of particles occurred seriously so that the size of individual particles was increased in aquatic solution.

• Environmental Analysis Health and Toxicology
• /
• 제19권1호
• /
• pp.25-32
• /
• 2004

Aim of the present study was the development of a bioassay which enables the detection of toxic effects of heavy metal ions to a bacterium, Escherichia coli. Inhibition effects of the metals on growth rates of the bacterium were studied in the absence or presence of fulvic acid. This method does not clearly differentiate among metals, but does detect overall AGB inhibition rate (toxicity) for 5 different heavy metals. The toxicity of the metals in the absence of fulvic acid in the same testing conditions was significantly increased in following order: Hg < Pb, Zn < Cd < Cu, whereas the inhibition rate (toxicity) in the presence of FA was shown to be increased In following order: Cd < Pb, Hg < Cu < Zn. The results of the present study indicate that this simple and fast biomonitoring assay with direct exposure of E coli. might be a valuable supplement to analytical methods of contaminated media.