• Journal of Environmental Science International
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• v.21 no.1
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• pp.97-103
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• 2012

Suspended wood waste was being inflow into the dam and the problem of waste disposal has been occurred. In this study, ethanol production using woody floater wastes was performed to estimate value in use for raw material of renewable energy. To achieve the goal, experiments of acid hydrolysis and ethanol fermentation using dam woody floater as raw materials for bioethanol was carried out. In the results of field survey in the chungju dam, kind of woody floater was mainly Japanese larch (Larix leptolepis) and hybrid poplar (Populus tomentiglandulosa). The results of sugar extraction showed that sugar content was higher in Larix leptolepis than Populus tomentiglandulosa. Extracted sugar from wood waste was effective consumed by yeast(P. Stipitis and S cerevisiae). In the experiment consumption of sugar including glucose, galactose and xylose, the consumption rate of S. cerevisiae is faster than that of P. stipitis. and efficiency for ethanol production is higer in S. cerevisiae than P. stipitis. Also it can be confirmed that resource as ethanol production using wood waste was available.

• Journal of Mushroom
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• v.13 no.2
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• pp.85-91
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• 2015

This study was initiated to evaluate ethanol production by a Korean isolate of white rot fungus Irpex consors. It was found that the fungus could produce ethanol by converting glucose, mannose, xylose, and cellobiose under semi-aerobic condition with yields of 0.23, 0.19, 0.21, and 0.17 g ethanol per g sugars, respectively. Furthermore, the strain produced ethanol by simultaneous saccharification and fermentation of rice straw treated with steam pressured boiling water, 3% NaOH, and 3% $H_2SO_4$ with maximum yields of 0.12, 0.15, and 0.19 g ethanol per g rice straw, respectively. These results suggested that I. consors could produce ethanol from the components of cellulose and hemicellulose including glucose, mannose, xylose, cellobiose as well as rice straw treated with steam pressured boiling water, dilute sodium hydroxide, and dilute sulfuric acid. This is the first report that I. consors mycelia produce ethanol from various sugars and lignocellulosic substance including rice straw.

• Microbiology and Biotechnology Letters
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• v.43 no.1
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• pp.16-21
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• 2015

In this study, a facile two-step pretreatment method was investigated for producing fermentable sugars. Rice straw was pretreated using electron beam irradiation (EBI) and 4-methylmorpholine-N-oxide (NMMO) prior to enzymatic hydrolysis. In the first stage, the EBI on the rice straw was carried out at various doses (100, 300, 500 kGy) and then, irradiated rice straw was stirred with NMMO solution at 120°C for 1 h for the second stage. The pretreated rice straw was hydrolyzed by cellulase 1.5 L (70 FPU/ml) and Novozyme-188 (40 CbU/ml) at 50°C for 24, 48, and 72 h. A sugar yield of 83.8% was obtained from the pretreated rice straw after 72 h of enzymatic hydrolysis. Also, FTIR and XRD results indicate that the pretreatment of the rice straw was effective due to the synergic effects of the two-step pretreatment. In conclusion, rice straw might be a potential substrate for bioethanol production by yeast fermentation.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.468-471
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• 2015

Microalgae have the advantages of being able to utilize the solar energy and culturing at a low cost. In particular, microalgae have a great potential in the production of biodiesel due to the high lipid content. Lipids produced from microalgae are converted to fatty acid methyl ester (FAME) by trans-esterification reaction and FAME is called a biodiesel in general. In addition, microalgae can also be utilized as a substrate for ethanol fermentation after saccharification reaction. In this study, three types of microalgae (Nanochloris, Dunaliella tertiolecta, Tetraselmis) were cultured and their lipid contents were compared. In addition, the effects of lighting period on the growth rate and lipid content were studied. Finally, the amounts of glucose produced from each saccharified microalgae were investigated. As a result, we demonstrated that D. tertiolecta has 43.6% higher lipid content and 22% higher glucose conversion than two others.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1243-1252
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• 2019

The purpose of this study is to investigate the optimum conditions of biomass pretreatment with potassium hydroxide (KOH) for efficient utilization of cellulose, hemicellulose and lignin from Miscanthus. The optimization of variables was performed by response surface methodology (RSM). The variation ranges of the parameters for the RSM were potassium hydroxide 0.2~0.8 M, reaction temperature 110~190℃ and reaction time 10~90 min. The optimum conditions of alkali pretreatment from Miscanthus were determined as follows: concentration of KOH 0.47 M, reaction temperature 134℃ and reaction time 65 min. At the optimum conditions, the yield of cellulose from the solid fraction after pretreatment was predicted to be 95% by model prediction. Finally, 66.1 ± 1.1% of cellulose were obtained by verification experiment under the optimum conditions. The order contents of solid extraction were hemicellulose 26.4 ± 0.4%, lignin 3.7 ± 0.1% and ash 0.5 ± 0.04%. The yield of ethanol concentration of 96% was obtained using separated saccharification and fermentation.

• Journal of Applied Biological Chemistry
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• v.59 no.3
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• pp.215-220
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• 2016

Abstract Secondary cell wall is the most abundant biomass produced by plants. Plant secondary cell wall is composed of a complex mixture of cellulose, hemicellulose, and lignin. Lignin, a phenolic polymer that hinders the degradation of cell wall polysaccharides to simple sugars destined for fermentation to bio-ethanol. Cell wall biosynthesis pathway-specific biomass engineering offers an attractive 'genetic pretreatment' strategy to improve bioenergy feedstock. Recently, we found a transcription factor, MYB7, which is a transcriptional switch that may turns off the genes necessary for lignin biosynthesis. To gain insights into MYB7 mediated transcriptional regulation, we first established a dominant suppression system in Arabidopsis by expressing MYB7-SRDX. Then we used a transient transcriptional activation assay to confirm that MYB7 suppress the transcription of the lignin biosynthetic gene. Taken together, we conclude that MYB7 function as a repressor of the genes involved in the lignin biosynthesis.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.45-51
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• 2014

This is to study the effects of various pretreatment methods of agricultural residue, corn stover, and to compare the feature and pros and cons of each method including dilute sulfuric acid (DSA), soaking in aqueous ammonia (SAA), and ammonia recycle percolation (ARP). In order to convert corn stover to ethanol, various pretreatments followed by simultaneous saccharification and co-fermentation (SSCF) were tested and evaluated in terms of ethanol yield. With 3%, w/w of glucan loading using ARP-, DSA-, and SAA-treated solids, SSCFs using recombinant E. coli strain (ATCC$^{(R)}$ 55124) with commercial enzymes (15 FPU of Spezyme CP/g-glucan and 30 CBU/g-glucan enzyme loading) were tested. In the SSCF tests, 87, 90, and 78% of theoretical maximum ethanol yield were observed using ARP-, DSA-, and SAA-treated solids, respectively, which were 69, 58, and 74% on the basis of total carbohydrates (glucan + xylan) in the untreated corn stover. Ethanol yield of SAA-treated solid was higher than those of ARP- and DSA-treated solids. In addition, SSCF test using treated solids plus pretreated hydrolysate indicated that the DSA-treated hydrolysate showed the strongest inhibition effect on the KO11 strain, whereas the ARP-treated hydrolysate was found to have the second strongest inhibition effect. Bioconversion scheme using SAA pretreatment and SSCF can make the downstream process simple, which is suggested to produce ethanol economically because utilization of hemicellulose in the hydrolysate is not necessary.

• KSBB Journal
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• v.24 no.5
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• pp.439-445
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• 2009

The process for ethanol production requires lignocellulosic biomass to be hydrolyzed to generate monomeric sugars for the fermentation. During hydrolysis step, a monomeric sugars and a broad range of inhibitory compounds (furan derivatives, weak acids, phenolics) are formed and released. In this study, we investigated the effects of inhibitory compounds on the fermentative performance of Saccharomyces cerevisiae K35 and Pichia stipitis KCCM 12009 in ethanol production, two yeast strains were fermented in the synthetic medium including six inhibitory compounds such as 5-hydroxymethylfurfura (5-HMF), furfural, acetic acid, syringaldehyde, vanillic acid and syringic acid. Ethanol of over 40 g/L was produced by two yeast strains in the absence of inhibitory compounds, respectively. Most inhibitory compounds except acetic acid had a little effect on the ethanol production, but acetic acid showed high inhibition effect on the cell growth and ethanol production.