• 생명과학회지
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• 제18권2호
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• pp.162-166
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• 2008

본 연구는 플라스크 배양을 통해 B. indica L3 균주를 가지고 PS-7을 생산할 수 있는 최적 조건을 조사하기 위해서 수행하였다. RSM을 통한 배지의 최적화 실험에서는 whey lactose, glucose, ammonium nitrate 세 가지의 독립변수의 조성에 따라 배양 72시간에 해당하는 DCW, PS-7, 그리고 점도의 변화에 대한 결과를 관찰하였다. 결정 계수(R square)의 값은 PS-7 생산량, DCW, 점성에서 각각 0.72, 0.64, 0.85로 신뢰성 있는 값을 획득하였다. Whey lactose와 glucose의 조합에 따른 PS-7 생산에 미치는 효과를 살펴보면 whey lactose (2%), glucose (1%)에서 최적의 PS-7 생산을 나타내었다. 결론적으로 glucose에 whey lactose를 기반으로 하는 배지 첨가와 C/N 비율이 PS-7의 생산에 큰 영향을 미침을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제19권3호
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• pp.291-298
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• 2009

The carbon metabolism of newly isolated Clostridium tyrobutyricum JM1 was investigated at varying initial glucose concentrations (27.8-333.6mM). Because an understanding of metabolic regulations was required to provide guidance for further effective metabolic design or optimization, in this case, maximizing hydrogen production, carbon and energy balances by C. tyrobutyricum JM1 were determined and applied in anaerobic glucose metabolism. The overall carbon distribution suggested that initial glucose concentrations had strong influence on the stoichiometric coefficients of products and the molar production of ATP on the formation of biomass. C. tyrobutyricum JM1 had a high capacity for hydrogen production at the initial glucose concentration of 222.4 mM with high concentrations of acetate and butyrate.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.725-730
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• 2003

Three recombinant Saccharomyces cerevisiae strains showing different levels of xylose reductase activity were constructed to investigate the effects of xylose reductase activity and glucose feed rate on xylitol production. Conversion of xylose to xylitol is catalyzed by xylose reductase of Pichia stipitis with cofactor NAD(P)H. A two-substrate fermentation strategy has been employed where glucose is used as an energy source for NADPH regeneration and xylose as substrate for xylitol production. All recombinant S. cerevisiae strains Yielded similar specific xylitol productivity, indicating that xylitol production in the recombinant S. cerevisiae was more profoundly affected by the glucose supply and concomitant It generation of cofactor than the xylose reductase activity itself. It was confirmed in a continuous culture that the elevation of the glucose feeding level in the xylose-conversion period enhanced the xylitol productivity in the recombinant S. cerevisiae.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1331-1337
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• 2006

A mathematical model has been proposed for the batch culture of Agaricus blazei with mixed carbon sources of glucose and dextrin. In the proposed model, the metabolism of A. blazei was divided into three parts: cell growth, exopolysaccharides (EPS) production, and another EPS production pathway activated by dextrin hydrolysis. Each pathway was described mathematically and incorporated into the mechanistic model structure. Batch cultures were carried out with six different carbon source compositions. Although parameters were estimated by using the experimental data from the two extreme cases such as glucose only and dextrin only, the model represented well the profiles of glucose, cell mass, and EPS concentrations for all the six different carbon source mixtures, showing a good interpolation capability. Of note, the lag in EPS production could be quite precisely predicted by assuming that the glucose-to-cell mass ratio was the governing factor for EPS production.

• Journal of Microbiology and Biotechnology
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• 제30권12호
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• pp.1944-1949
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• 2020

Mutant sugar transporter ScGAL2-N376F was overexpressed in Kluyveromyces marxianus for efficient utilization of xylose, which is one of the main components of cellulosic biomass. K. marxianus ScGal2_N376F, the ScGAL2-N376F-overexpressing strain, exhibited 47.04 g/l of xylose consumption and 26.55 g/l of xylitol production, as compared to the parental strain (24.68 g/l and 7.03 g/l, respectively) when xylose was used as the sole carbon source. When a mixture of glucose and xylose was used as the carbon source, xylose consumption and xylitol production rates were improved by 195% and 360%, respectively, by K. marxianus ScGal2_N376F. Moreover, the glucose consumption rate was improved by 27% as compared to that in the parental strain. Overexpression of both wild-type ScGAL2 and mutant ScGAL2-N376F showed 48% and 52% enhanced sugar consumption and ethanol production rates, respectively, when a mixture of glucose and galactose was used as the carbon source, which is the main component of marine biomass. As shown in this study, ScGAL2-N376F overexpression can be applied for the efficient production of biofuels or biochemicals from cellulosic or marine biomass.

• Animal Bioscience
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• 제37권4호
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• pp.631-639
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• 2024

Objective: This study evaluates goat sperm motility in response to metabolic substrates and various inhibitors, aiming to assess the relative contribution of glycolysis and mitochondrial oxidation for sperm movement and adenosine triphosphate (ATP) production. Methods: In the present study, two main metabolic substrates; 0 to 0.5 mM glucose and 0 to 30 mM pyruvate were used to evaluate their contribution to sperm movements of goats. Using a 3-chloro-1,2-propanediol (3-MCPD), a specific inhibitor for glycolysis, and carbonyl cyanide 3-chlorophenylhydrazone as an inhibitor for oxidative phosphorylation, cellular mechanisms into ATP-generating pathways in relation to sperm movements and ATP production were observed. Data were analysed using one-way analysis of variance for multiple comparisons. Results: Sperm motility analysis showed that either glucose or pyruvate supported sperm movement during 0 to 30 min incubation. However, the supporting effects were abolished by the addition of a glycolysis inhibitor or mitochondrial uncoupler, concomitant with a significant decrease in ATP production. Although oxidative phosphorylation produces larger ATP concentrations than those from glycolysis, sperm progressivity in relation to these two metabolic pathways is comparable. Conclusion: Based on the present study, we suggest that goat sperm use glucose and pyruvate to generate cellular energy through glycolysis and mitochondrial respiration pathways to maintain sperm movement.

• KSBB Journal
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• 제21권4호
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• pp.267-272
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• 2006

주정공장 근처 토양에서 분리한 에탄올 발효균주 KJ는 Saccharomyces italicus로 판명되었으며, glucose가 최적의 탄소원으로 확인되었다. 균주 KJ의 최적배양조건은 온도 $30^{\circ}C$, 초기 당 농도 10%, 초기 pH 5 근방, 혐기조건으로 판명되었다. 초기 탄소원이 동일한 조건에서 YM배지(glucose 10 g/L)와 SFW배지(RS 10 g/L)에서 에탄올 생산은 각각 5.34, 5.68 g/L로 나타나, KJ균주는 음식물쓰레기 당화액을 에탄올 발효배지로 적절하게 사용될 수 있음이 확인되었다. 에탄올 생산배양에 SFW의 이용은 에탄올생산단가를 대폭 낮추게 하여 대체에너지인 에탄올의 대량생산기술의 경제성을 확보하는데 크게 기여할 것이다.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2004년도 International Meeting of the Microbiological Society of Korea
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• pp.101-104
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• 2004

Among biological hydrogen production processes, fermentative processes have some advantages. In this research, the hydrogen producing bacterium was isolated from domestic landfill area and identified as Enterobacter sp. The strain was named Enterobacter sp. SNU-1453. Important parameters for the hydrogen process include pH, temperature, concentration of initial glucose, and kind of sugars. The pH of the culture medium significantly decreased as fermentation proceeded due to the accumulation of various organic acids, and this inhibited the $H_2$ production seriously. When pH was controlled at pH 7.0, hydrogen production was 2614.5 m1/1 in 17 hours. The increase of glucose concentration resulted in higher $H_2$ production. The productivity of this strain was 6.87 mmol $H_2/l$ per hi on concentration of 25g glucose/l. Enterobacter sp. SNU-1453 could utilize various sugars. These results indicate that Enterobacter sp. SNU-1453 has a high potential as a fermentative $H_2$ producer.

• Journal of Microbiology and Biotechnology
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• 제18권8호
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• pp.1439-1444
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• 2008

The recombinant E. coli $\Delta$6 mutant (galR, glpK, gldA, IdhA, lacI, tpiA) was used to produce 1,3-propanediol (PD) from glucose. The 1,3-PD production increased with feedback control of the glucose concentration using fed-batch fermentation. The maximum 1,3-PD concentration produced was 43 g/l after 60 h of fermentation. Glycerol production was minimized when controlling the glucose concentration at less than 1 g/l. The expression levels of seven enzymes related to the 1,3-PD production metabolism were compared during the cell growth phase and 1,3-PD production phase, and their expression levels all increased during 1,3-PD production, with the exception of alcohol dehydrogenase.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.419-422
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• 2002

Fermentative hydrogen production by Citrobacter sp. Y 19 was investigated in batch culture. Optimal hydrogen production activity was observed at pH 6 - 7 and temperature of $36^{\circ}C$, and hydrogen yield and maximal hydrogen production rate were 1.12 mmol/mmol glucose and 32.3 mmol/g cell${\cdot}$h, respectively. With glucose as a substrate, the bacterium produced ethanol, acetate, and carbon dioxide as major glucose fermentation by-products. Y19 could utilize various sugars such as galactose, fructose, lactose, sucrose, and starch for cell growth and hydrogen production.