• KSBB Journal
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• v.30 no.6
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• pp.283-290
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• 2015

In this study was selected the cellulolytic microorganism and investigated optimum condition of cellulase production for the cellulosic bioethanol production. A bacterial strain Paenibacillus jamilae BRC15-1, was isolated from soil of domestic reclaimed land. For optimizing cellulase production from the selected strain, various culture parameters were investigated such as culture medium, pH (pH 4~10), temperature ($25{\sim}50^{\circ}C$) and culture time (2~72 h). As a result, P. jamilae BRC15-1 efficiently produced cellulase from cellulosic biomass under following conditions: 24 h of culture time (pH 7, $40^{\circ}C$) in manufactured media of CMC (carboxymethyl cellulose) with peptone. Optimum saccharifying condition of crude enzyme produced from P. jamilae BRC15-1 was identified on pH 6 and $40^{\circ}C$ of reaction temperature, respectively. This crude enzyme from P. jamilae BRC15-1 was used for saccharification of pretreated sweet sorghum (Sorghum bicolor var. dulciusculum Ohwi) bagasse under the optimal condition. Finally, pretreated sweet sorghum bagasse including 0.1 g of glucan was saccharified by crude enzyme of P. jamilae BRC15-1 into 2.75 mg glucose, 0.79 mg xylose and 1.12 mg arabinose.

• Microbiology and Biotechnology Letters
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• v.45 no.2
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• pp.162-167
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• 2017

For the production of bioethanol by the synchronous saccharification and fermentation (SSF) process, bio-capsule formation was attempted. Many saccharifying fungal strains and fermentative yeast strains were first screened. Aspergillus sp. BCNU 6200, Penicillium sp. BCNU 6201, and P. chrysogenum KACC 44363 were found to be excellent producers of saccharifying enzymes such as ${\alpha}$-amylase and glucoamylase. Saccharomyces cerevisiae IFO-M-07 showed the highest ethanol productivity among the tested strains. Secondly, we determined the optimal conditions for pellet formation, and those for bio-capsule formation. All the tested fungal strains formed pellets, and the optimal conditions for bio-capsule formation were $28^{\circ}C$ and 120 rpm. Lastly, SSF process was performed using a bio-capsule. An ethanol yield of 3.9% was achieved by using the Aspergillus sp. BCNU 6200 bio-capsule (Aspergillus sp. BCNU 6200 + S. cerevisiae IFO-M-07) at $30^{\circ}C$ with shaking at 120 rpm during the 10 days of incubation. The results provide useful information on the application of a bio-capsule in bioethanol production under the SSF process.

• 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.

• Microbiology and Biotechnology Letters
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• v.45 no.3
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• pp.236-242
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• 2017

The conversion of marine biomass to renewable energy has been considered an alternative to fossil fuels. Butanol, in particular, can be used directly as a fuel. In this experiment, the brown alga Undaria pinnatifida was selected as a biomass for biobutanol production. Hyper thermal (HT) acid hydrolysis was used as an acid hydrolysis method to produce monosaccharides. The optimal pretreatment conditions for U. pinnatifida were determined as slurry with 10% (w/v) U. pinnatifida content and 270 mM $H_2SO_4$, and heating at $160^{\circ}C$ for 7.5 min. Enzymatic saccharification was carried out with Celluclast 1.5 L, Viscozyme L, and Ultraflo Max. The optimal saccharification condition was 12 U/ml Viscozyme L. Fermentations were carried out for the production of acetone, butanol, and ethanol by Clostridium acetobutylicum KCTC 1724, Clostridium beijerinckii KCTC 1785, and Clostridium tyrobutyricum KCTC 5387. The fermentations were carried out using a pH-control. The optimal ABE fermentation condition determined using C. acetobutylicum KCTC 1724 adapted to 160 g/l mannitol. An ABE concentration of 9.05 g/l (0.99 g/l acetone, 5.62 g/l butanol, 2.44 g/l ethanol) was obtained by the consumption of 24.14 g/l monosaccharide with $Y_{ABE}$ of 0.37 in pH 5.0.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.277-283
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• 2017

To produce sweet liquor without artificial sweeteners, 8 traditional rice pre-treatment methods (juk, beombeok, seolgitteok, gumeongtteok, mulsongpyeon, injeolmi, gaetteok, and godubap) were analyzed in this study. The formation of sugars with the help of ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase using nuruk as a substrate has been previously confirmed. During the early stages of the pre-treatment processes, the amount of maltose produced (in descending order of its concentration) by ${\alpha}$-amylase was observed to be as follows: gaetteok > seolgitteok > beombeok > mulsongpyeon > juk > injeolmi > gumeongtteok > godubap. However, changes in maltose concentrations with respect to the pre-treatment processes after 48 hours were observed to be as follows: injeolmi > beombeok = godubap > gumeongtteok > gaetteok = mulsongpyeon > seolgitteok > juk. Maltose produced using either ${\alpha}$-amylase or ${\beta}$-amylase showed similar results. Glucoamylase produced 10 mg/ml of glucose during the godubap process, which was the highest amount of glucose among all the methods. Moreover, when ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase were used concurrently, glucoamylase increased glucose production in the later stages. Therefore, the possibility of producing sweet liquor without employing artificial sweeteners was confirmed, even if the amount of sugar in the liquor varied with the pre-treatment process.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.431-435
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• 2016

The aim of this study was to investigate the effect of gamma irradiation on the pretreatment of wood chips with NaOH solution. The degree of saccharification was quantified by measuring reducing sugar and glucose concentrations after enzymatic hydrolysis. After pretreatment with 10 g/L NaOH, the wood chips were irradiated at the doses of 0, 50, 100, and 200 kGy, respectively. Among the irradiated samples, wood chips irradiated at the dose of 200 kGy had the highest reducing sugar concentration of 12.2 g/L. Also, to define the effect of irradiation before pretreatment, the wood chips were first gamma-irradiated and then pretreated with NaOH. When the NaOH treatment was conducted after irradiation at 200 kGy, the reducing sugar content was further increased to 13.4 g/L and glucose content of the wood chip was as high as 7.9 g/L. These results suggest that gamma irradiation may be the promising method for pretreatment of cellulose biomass.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.494-500
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• 2016

In order to remove acetyl group from yellow poplar, deacetylation was performed using sodium hydroxide (NaOH) prior to oxalic acid pretreatment. During the deacetylation ($60^{\circ}C$ for 80 min, 0.8% NaOH), most of the acetyl group were removed from hemicellulose. Simultaneous saccharification and fermentation (SSF) and semi-SSF were carried out based on solid loading (10, 12.5, 15%) of deacetylated biomass and pre-hydrolysis with enzymes (0, 6, 12, 24 h). The highest ethanol was obtained as 26.73 g/L after 120 h when 10% of biomass was used for SSF. It is corresponding to 88.41% of theoretical ethanol yield. At the 12.5% and 15% of biomass loading, the highest ethanol was obtained from 6 h pre-hydrolysis. It was 32.34 g/L and 27.15 g/L, respectively, and corresponding to ethanol yield of 85.58 and 59.87%. In order to remove fermentation inhibitors from hydrolysates, overliming was performed using calcium hydroxide ($Ca(OH)_2$). The highest ethanol was 5.28 g/L after 72 h of fermentation.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.507-514
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• 2013

In this study, oxalic acid pretreatment of empty fruit bunch (EFB) was performed at different pretreatment temperatures. Also, we evaluated oxalic acid recovery from hydrolysate by electrodialysis. The fermentable sugar concentration in hydrolysate was high at more than $20g/{\ell}$, when pretreatment was carried out at $150^{\circ}C$. At the same time, ethanol production was $3.78g/{\ell}$ after 72 h which correspond to the ethanol yield of 0.21 g/g. On the other hydrolysate (160, $170^{\circ}C$), fermentable sugar was not consumed by Pichia stipitis during fermentation. Most of the oxalic acid was recovered and some of the fermentation inhibitors were removed by electrodialysis. For the electrodialysis treated hydrolysate, ethanol production was increased compared to the original hydrolysate. The highest ethanol production was $5.38g/{\ell}$ after 24 h which correspond to the yield of 0.33 g/g. The ethanol production by simultaneous saccharification and fermentation (SSF) under all pretreatment conditions was more than $15g/{\ell}$ after 96 h. The highest ethanol production was $20.54g/{\ell}$, when pretreatment was performed at $170^{\circ}C$. In particular, ethanol production was increased, when electrodialysis treated hydrolysate was used for SSF.

• The Korean Journal of Food And Nutrition
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• v.29 no.5
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• pp.698-705
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• 2016

This study aimed to evaluate the quality characteristics of Gastrodia elata Blume fermented by lactic acid bacteria after saccharifying by 3 methods including enzyme, malt, and rice-nuruk. The lactic acid bacteria (LAB), Pediococcus inopinatus BK-3, isolated from kimchi could reduce the unpleasant taste and odor of Gastrodia elata Blume. The total acidity value of Gastrodia elata fermented by LAB on the malt and rice-nuruk extract solution for 3 days was 2.23% and 2.33%, respectively. After saccharification by malt and rice-nuruk extract solution for 3 days, the viable cell number of fermented Gastrodia elata was 9.14 log cfu/mL and 9.27 log cfu/mL, respectively. The total acidity values were increased above 3.35% by malt and rice-nuruk extract solution for 8 days. Thus, the viable cell number was the highest by malt and rice-nuruk extract solution fermentation for 3 days. The amino acid content of Gastrodia elata fermented by LAB after saccharification by malt extract solution was higher than that of other saccharifying methods. The free sugar content and p-hydroxybenzyl derivatives induced by the enzyme method were higher than those of other saccharifying methods. The overall acceptability was the highest at 4.2 point in Gastrodia elata fermented by malt extract solution.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.112.1-112.1
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• 2011

쌀을 주식으로 하는 우리나라의 여건상 연간 추정치로 싸라기 약 12만톤, 미강 약 49만톤, 왕겨 약 79만톤의 벼 도정 부산물이 발생하고 있다. 본 연구에서는 벼 도정 부산물 중 비식량 자원인 왕겨를 대상으로 고효율 효소 당화를 위한 바이오매스 전처리 방법을 탐색하였다. 왕겨 원시료의 초기 조성은 셀룰로스 34.5%, 헤미셀룰로스 20.5%, 리그닌 25.3%, 회분 14.6%로 나타났는데, 억새 등 초본계 바이오매스와 비교하여 특이하게 높은 성분은 회분으로 이는 벼에 대한 규산질 비료의 시용에서 기인한 것이다. 바이오매스 전처리에 많이 사용되는 암모니아, 희황산 용매와 규산염에 침식성을 가지는 가성소다 용매를 이용하여 각 용매별 단독 및 알칼리-산 복합 처리 하였을 때 효소 가수분해 효율, 고상시료 성분변화 등을 상호 비교하였다. 예비실험을 통하여 암모니아 처리조건은 15%(w/w) $150^{\circ}C$ 20분, 가성소다 처리조건은 1.5%(w/w) $150^{\circ}C$ 20분, 희황산 처리조건은 1.0%(w/w) $150^{\circ}C$ 10분으로 설정하였다. 암모니아 단독, 희황산 단독, 암모니아-희황산 복합 처리 시료의 효소 가수분해 효율은 각각 37.8%, 39.1%, 42.8%로 약 40%선에서 큰 차이가 없었다. 반면 가성소다 단독, 가성소다-희황산 복합 처리시료의 효소 가수분해 효율은 각각 62.7%, 82.8%로 나타나 앞선 3가지 처리방법 대비 50%, 100%에 가까운 효소 가수분해 효율 향상을 보였다. 이 때 전처리 고상시료의 성분 변화를 살펴보면 회분 함량에서 큰 차이를 보였는데 암모니아 단독, 가성소다 단독, 희황산 단독, 암모니아-희황산 복합, 가성소다-희황산 복합 처리에서 각각 47.8%, 77.1%, 43.5%, 55.8%, 94.7%의 회분 성분 기각률(rejection rate)을 나타냈다. 이는 왕겨 효소 가수분해 효율의 최대 저해요인이 회분임을 추정할 수 있다. 왕겨 전처리 알칼리 용매는 암모니아보다 가성소다가 더 효과적이었고 희황산 복합 처리시 그 효과가 크게 상승하였다. 따라서 규산염(회분) 함량이 높은 바이오매스는 고온 고압 조건에서 가성소다 용액으로 처리한 후 그 고상분을 희황산 용액으로 복합 처리하는 시스템이 효소 당화 증진에 매우 유리함을 확인하였다.