• Journal of Life Science
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• v.25 no.12
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• pp.1450-1457
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• 2015

To overcome the depletion of fossil fuels and environmental problems in future, the research and production of biofuels have attracted attention largely. Thermophilic microorganisms produce effective and robust enzymes which can hydrolyze plant biomass and survive under harsh bioprocessing conditions. Caldicellulosiruptor bescii, which can degrade unpretreated plants and grow on them, is the one of the best candidates for consolidated bioprocessing (CBP). C. bescii can hydrolyze pectin efficiently as well as the major plant cell wall components, cellulose and hemicelluloses. Many glycosyl hydrolases and carbohydrate lyases with multidomain structure play an important role in plant biomass decomposition. Recently genetic tools for metabolic engineering of C. bescii have developed and bioethanol production from unpretreated biomass is achieved in C. bescii. Here, we review the recent studies for biomass degradation by C. bescii and bioethanol production in C. bescii in order to provide information about metabolic engineering of themophilic bacteria and biofuel development.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.35-41
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• 2012

This paper proposes a new methodology for the real-time on-line quality monitoring of biofuel processes through the integration of infrared spectroscopy and chemometrics. A method of Partial Least Squares (PLS) in Chemometrics is employed for quantitative analysis of key components in bioethanol products. After a number of preprocessing methods and variable importance in projection (VIP) are used, Savitzky-Golay method showed the best performance in terms of spectrum correction, noise reduction, and model maintenance. The proposed method allows us to economically forecast the concentration of multiple impurities encountered with the production of bioethanol. The proposed system is also accurate enough ($R^2$ > 0.99) to replace the laboratory analysis.

• Journal of Plant Biotechnology
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• v.48 no.4
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• pp.278-288
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• 2021

The development of bioenergy through biomass has gained importance due to the increasing rates of fossil fuel depletion. Biomass is important to increase the productivity of bioethanol, and production of biomass with high biomass productivity, low lignin content, and high cellulose content is also important in this regard. Inorganic salts are important in the cultivation of biomass crops for the production of biomass with desirable characteristics. In this study, the roles of various inorganic salts in biomass and bioethanol production were investigated using an in vitro tobacco culture system. The inorganic salts evaluated in this study showed dramatic effects on tobacco plant growth. For example, H₂PO₄ substantially improved plant growth and the root/shoot (R/S) ratio. The chemical compositions of tobacco plants grown in media after removal of various inorganic salts also showed significant differences; for example, lignin content was high after Mg²⁺ removal treatment and low after K⁺ treatment and H₂PO₄ removal treatment. On the other hand, NO₃^- and H₂PO₄ treatments yielded the highest cellulose content, while enzymatic hydrolysis yielded the highest glucose concentration ratio 24 h after NH₄⁺ removal treatment. The ethanol productivity after H₂PO₄ removal treatment was 3.95% (w/v) 24 h after fermentation and 3.75% (w/v) after 36 h. These results can be used as the basis for producing high-quality biomass for future bioethanol production.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.21-29
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• 2015

In this study, the feasibility of utilizing wood chips from pitch pine (Pinus rigida) was evaluated for bioethanol production by an organosolv pretreatment and enzymatic saccharification. When wood chips from pitch wood were pretreated with 75% (v/v) ethanol and 1.7% sulfuric acid as a catalyst at H-factor 2000, average pulp yield was 43.3%, which pretreated wood fibers showed higher glucan (55.8%) and lower lignin (12.2%) contents than untreated control (43.9% glucan and 27.8% lignin). After enzymatic saccharification, the organosolv pulps with 56.2% delignification rate reached above 97% conversion rate of cellulose to glucose. These results indicated that increasing the delignification rate causes micro pores on the surface of organosolv pulps resulting in improved the accessibility of enzyme onto the substrate. Moreover, it was in agreement with the SEM examination of wood fibers.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.241-248
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• 2015

Tuak is a traditional alcoholic beverage, one of the most widely known in the North Sumateran region of Indonesia. It is produced by a spontaneous fermentation process through the application of one or more several kinds of wood bark or root, called raru (Xylocorpus wood bark or a variety of forest mangosteen), into the sap water of sugar palm (Arenga pinnata) for 2−3 days. In this research, yeast that are potentially useful for ethanol production was isolated from Tuak and identified. Based on analysis of D1/D2 domain sequence of LSU (large subunit) rRNA genes, those isolated yeast strains, HT4, HT5, and HT10 were identified as Candida tropicalis. Fermentation test of these C. tropicalis isolates displayed an ability to produce 6.55% (v/v) and 4.58% ethanol at 30℃ and 42℃, respectively. These results indicated C. tropicalis isolates more rapidly utilize glucose and obtain higher levels of the production of ethanol at the higher temperature of 42℃ than S. cerevisiae, a common yeast used for bioethanol fermentation.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.358-364
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• 2016

The combustion and exhaust emission characteristics in a spark ignition (SI) engine with various test fuels (bioethanol - gasoline blends) and air-fuel ratio were investigated in this research. To investigate the influence of the excess air ratio and ethanol blends on the combustion characteristics such as the cylinder pressure, rate of heat release (ROHR), and fuel consumption rate were analyzed. In addition, the reduction effects of exhaust emissions such as carbon monoxide (CO), unburned hydrocarbon (HC), and oxides of nitrogen (NOx) were compared with those of neat gasoline fuel under the various excess-air ratios. The results showed that the peak combustion pressures and the ROHR of bioethanol fuel cases were slightly higher than those of gasoline fuel at all test ranges and fuel ratio. As compared with gasoline fuel (G100) at each given excess air ratio, BSFC of bio-ethanol was increased. The CO, HC, NOx emissions of bio-ethanol blends were lower than those of gasoline fuel under overall experimental conditions.

• KSBB Journal
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• v.29 no.4
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• pp.297-302
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• 2014

The autoclaving assisted by an irradiation pretreatment method was developed without toxic chemicals to produce fermentable sugars for their conversion to bioethanol. In the first step, electron beam irradiation (EBI) of rice straw was performed at various doses. The electron beam-irradiated rice straw was then autoclaved with DI water at $120^{\circ}C$ for 1 h. A total sugar yield of 81% was obtained from 300 kGy electron beam-irradiated rice straw after 72 h of enzymatic hydrolysis by Cellulase 1.5L (70 FPU/mL) and Novozyme-188 (40 CbU/mL). Also, the removal of hemicellulose and lignin was 32.0% and 32.5%, respectively. This result indicates that the environmentally-friendly pretreatment method of rice straw by an electron beam irradiation could be applied for bioethanol production in plant.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.135-139
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• 2017

BACKGROUND: Identification and characterization of endophytic yeasts inhabiting the roots of Ulmus parvifolia Jacq. and Quercus salicina Blume require biotechnological and culture-based techniques. METHODS AND RESULTS: Homogenized U. parvifolia and Q. salicina root samples were spread onto four types of agar medium containing ancgtibiotics, L-sorbose, and Triton X-100. In total, 25 yeast strains were isolated and subjected to phylogenetic analysis based on their internal transcribed spacer region sequences. The results revealed that the yeast genera Cyberlindnera (12 isolates) and Cryptococcus (1 isolate) were associated with roots of U. parvifolia; and the genera Rhodotorula (8 isolates), Trichosporon (3 isolates), and Kluyveromyces (1 isolate) were associated with roots of Q. salicina. Additionally, a Kluyveromyces isolate produced a detectable level of bioethanol. The yeast strains reported herein may be used in industrial production of biosurfactants and bioethanol. CONCLUSION: Our findings revealed that the endophytic yeast genera Cyberlindnera and Cryptococcus predominated in roots of U. parvifolia; and the genera Rhodotorula (8 isolates), Trichosporon (3 isolates), and Kluyveromyces (1 isolate) predominated in roots of Q. salicina. Additionally, Kluyveromyces isolates produced a detectable level of bioethanol.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.274-286
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• 2009

Lignocellulosic biomass is the most abundant raw material for bioconversion in many country. However the high costs for pretreatment and enzymatic hydrolysis currently deter commercialization of lignocellulosic biomass, especially wood biomass which is considered as the most recalcitrant material for enzymatic hydrolysis mainly due to the high lignified structure and the nature of the lignin component. Therefore, overcoming recalcitrance of lignocellulosic biomass for converting carbohydrates into intermediates that can subsequently be converted into biobased fuels and biobased products is the primary technical and economic challenge for bioconversion process. This study was mainly reviewed on the research trend of pretreatment with lignocellulosic biomass in bioethanol production process.

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.42-47
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• 2024

Limonene was separated from waste citrus peels by a vacuum drying process with a venturi, and bioethanol was produced from dried citrus peels. Vacuum drying using venturi was very effective in removing moisture and limonene compared to hot air drying and natural drying. Citrus peels prepared by venturi vacuum drying were the most suitable for ethanol fermentation. The moisture and limonene content of the citrus peels dried for 15 hours were 17.0% and 3.2%, respectively. By venturi vacuum drying, essential oil containing limonene and floral water were obtained, respectively. The amount of essential oil separated by venturi vacuum drying was 4.21 mL essential oil/kg citrus peel, 79.9% of the separated essential oil was limonene.