• BMB Reports
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• v.45 no.2
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• pp.59-70
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• 2012

Carbon catabolite repression (CCR) is a key regulatory system found in most microorganisms that ensures preferential utilization of energy-efficient carbon sources. CCR helps microorganisms obtain a proper balance between their metabolic capacity and the maximum sugar uptake capability. It also constrains the deregulated utilization of a preferred cognate substrate, enabling microorganisms to survive and dominate in natural environments. On the other side of the same coin lies the tenacious bottleneck in microbial production of bioproducts that employs a combination of carbon sources in varied proportion, such as lignocellulose-derived sugar mixtures. Preferential sugar uptake combined with the transcriptional and/or enzymatic exclusion of less preferred sugars turns out one of the major barriers in increasing the yield and productivity of fermentation process. Accumulation of the unused substrate also complicates the downstream processes used to extract the desired product. To overcome this difficulty and to develop tailor-made strains for specific metabolic engineering goals, quantitative and systemic understanding of the molecular interaction map behind CCR is a prerequisite. Here we comparatively review the universal and strain-specific features of CCR circuitry and discuss the recent efforts in developing synthetic cell factories devoid of CCR particularly for lignocellulose-based biorefinery.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.77-86
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• 2021

In this study, to use as basic data for the organic waste resource energy incentive system, the energy efficiency is evaluated through the mass balance and energy balance calculation results of the anaerobic digester where food waste, food waste leachate and various organic wastes are treated. As a result of the mass balance analysis for 11 biogasification facilities, it was confirmed that 21.1% of process water and 25.7% of tap water were input in large amounts, excluding organic waste. Accordingly, it accounted for 87.6% of the total effluent of linked treated water. In addition, considering that 15.7% of the total input volume is converted to biogas and the average total solids (TS) is 22%, an average material conversion rate of 75% was confirmed. As a result of the energy balance analysis, the energy conversion rate was confirmed to be 78.5% on average by analyzing the biogas calorific value compared to the potential energy of the influent. The average biogas production efficiency including external energy sources for biogas production was 69.4%, and the biogas plant efficiency to which unused effluent energy was applied was 58.9% on average.

• Journal of Convergence for Information Technology
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• v.11 no.6
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• pp.40-48
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• 2021

The paper dealt with the fact that the green deal took place when the demand for electrical energy surged. However, the procurement of electric vehicles and much of the electric energy of the future still depends on fossil fuels. Accordingly, the importance of the IT industry is highlighted, and the demand for hydrogen-electric vehicles and related industries increases. The method of this study investigated the relevance of EV charging as a future next-generation power source rather than the electric energy demand of the IT industry. This study derives the correlation between industrial electricity and household energy PPP according to economic growth through empirical regression analysis. As the result, it was found that the amount of change, including electric and next-generation electric vehicles, was significant for on thirds of the countries in the change in purchasing power compared to GDP. This affects overall purchasing power as twelve out of thirty two countries with EV demand (Italy, Canada, Switzerland, Poland, Slovenia, Germany, Slovakia, Finland, Sweden, Czech Republic, Estonia, Denmark) are more sensitive to electric energy. This is related to the charging of EVs or hydrogen as the next-generation power of the future rather than the electric energy demand of the IT industry. By preventing waste of unused electricity of IT-electric energy sources and charging-preserving hydrogen electricity, it seems indispensable to prepare for the national IT power conservation buffer facility for supply and demand in future growth.