• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.143-149
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• 1998

Sugars in Korean beer(3 brands) and Japanese beer(21 brands) were studied by HPLC and TLC. Total sugar of beer were estimated to 1.71∼3.93%(average 3.15%). Ethanol 4.5% class beers were estimated to 3.24% for Korean brands and 2.5% for Japanese brands. Ethanol 5% and 5.5% class beer were estimated to contain 3.2% for Japanese brands, respectively. Maltooligosaccharide series from glucose to maltodecaose were detected in the test of TLC and HPLC. No fermentable maltooligosaccarides and limit dextrin were estimated to 2.32%. But sugars in Korean Sikhye, rice drink saccharifide by malt, were not detected maltooligosaccharide series form maltotetraose to maltoheptaose.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.141-148
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• 2012

In order to study the utilization of brown seaweed Laminaria japonica as an alternative renewable feedstock for bioethanol production, the properties of acid hydrolysis and ethanol fermentation were investigated. The acid hydrolysis enhanced the final yield of fermentable sugars, which led great increase of ethanol productivity. The maximum yield of reducing sugars reached 135 mg/g-dry Laminaria japonica after 1.0N sulfuric acid-hydrolysis at $130^{\circ}C$ for 6 h. The Saccharomyces cerevisiae (ATCC 24858) could ferment $C_6$-sugars like glucose, galactose and mannose into ethanol, but not $C_5$-sugars like arabinose and xylose. Optimal fermentation time varied with sugars; 48 h for glucose, 72 h for galactose, and 96 h for mannose. Nevertheless, the ethanol yield from the hydrolysate reached 242 mg/g-dry Laminaria japonica after fermentation by the S. cerevisiae at $35^{\circ}C$ for 96 h, which corresponds to approximately 4 times more than the theoretical yield from total reducing sugars in the hydrolysates. It indicates that the non-reducing sugars or oligosaccharides dissolved in the hydrolysate played an important role in producing bioethanol. The ethanol concentration linearly increased from 2.4 to 9.2 g/L, while the ethanol yield per dry weight of biomass decreased from 242 to 185 mg/g, with increasing the ratio of biomass to acid solution from 1 to 5% (w/v). The bioethanol yield estimated was approximately 7,400~9,600 kg/ha/year, and indicated that Laminaria japonica is a promissing feedstock for bioethanol production.

• Journal of Mushroom
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• v.14 no.4
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• pp.127-135
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• 2016

Cellulose is the most abundant organic polymer constituent of the cell wall of green plants and of various forms of algae. The complexity of lignocellulosic biomass is a major challenge in industrial research. Most mushroom species that naturally grow on soil or wood possess cellulases and the corresponding enzymatic system and, potential candidates for the direct bioconversion of softwood polysaccharides into fermentable sugars. However, there have been fewer studies on mushroom cellulases than on fungi such as Trichoderma spp., exploit the full potential of mushroom cellulases. This review will focus on the current status ofmushroom cellulase research and applications and will provide insight into promising future prospects.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.1-7
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• 2014

Dissolving part of xylan and lignin in lignocellulosic biomass by base can be used as pretreatment technique. Cork oak was pretreated with sodium hydroxide solution and the pretreatment effects were evaluated with two critical factors - NaOH concentration and pretreatment temperature. Some of xylan and lignin were removed by base pretreatment. At $90^{\circ}C$ and 13% NaOH pretreatment, 22.0% of lignin and 78.8% of xylan removed by base treatment. Enzymatic hydrolysis of cork oak which was pretreated at higher temperature or concentration was further improved. After pretreatment of cork oak with 13% NaOH at $90^{\circ}C$, the conversion rate of cellulose to fermentable sugars were reached up to 91.3%. At ethanol fermentation with enzymatic hydrolysate from different pretreatment conditions, all enzymatic saccharification liquids were well fermented by Saccharomyces cerevisiae.

• Microbiology and Biotechnology Letters
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• v.27 no.2
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• pp.145-152
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• 1999

Brettanomyces custersii CBS 5512 which has reported as a thermotolerant glucose-cellobiose co-fermentable yeast strain was mutated with UV and NTG to improve ethanol yield at higher than 4$0^{\circ}C$ B. custersii H1-23, H1-39, H1-55 and H1062 were finally selected for hyper-fermentable strains at higher than 4$0^{\circ}C$ from thermotolerant 7510 colonies through 5th selection. Among the selected strains, H1-39 mutant had better fermentability at 4$0^{\circ}C$ and 43$^{\circ}C$ from different concentrations of glucose. H1-39 and H1-23 mutants yielded more than 70% of the theoretical ethanol yield in 4 and 8% mixed sugars at above 4$0^{\circ}C$, which was 5-11% higher than those by original strain. Especially, H1-39 mutant had better fermentability in 4% mixed sugar. It showed 78.5% of the theoretical yield at 4$0^{\circ}C$ and 72.2% of the theoretical yield at 43$^{\circ}C$. On the other hand, theoretical yield of ethanol by H1-39 mutant in 8% mixed sugar at 4$0^{\circ}C$ and 43$^{\circ}C$ were 75.2% and 70.2%, respectively. Theses values increased up to 7-11% as compared to those by orginal strain. By the simultaneous saccharification and fermentation, ethanol production by H1-39 mutant increased up to more than 23% as compared to that by original strain.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.397-405
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• 2009

In this study, we investigated the potential of producing bioethanol from Liriodendron tulipifera by using oxalic acid pretreatment. Amounts of fermentable sugars, mostly xylose and glucose, in the liquid fraction (hydrolysate) was $40.22g/{\ell}$ after the biomass was pretreated with 0.037 g/g of oxalic acid for 20 minutes at $160^{\circ}C$. Production amounts of ethanol was $8.6g/{\ell}$ from the 72 hours of simultaneous saccharification and fermentation (SSF) on solid fraction of the pretreated sample. At the same condition, when the reaction time increased to 40 minutes, $32.66g/{\ell}$ of fermentable sugars in the hydrolysate and $9.5g/{\ell}$ of ethanol was produced from the process of pretreatment and SSF. As a result of analyzing the fermentation inhibitors, such as acetic acid, 5-HMF, furfural and total phenolic compounds, as the reaction time increased, the amount of the fermentation inhibitors in the hydrolysate increased. Production of the fermentation inhibitors was more affected by initial concentration of oxalic acid rather than reaction time. $3.39{\sim}5.78g/{\ell}$ of acetic acid was produced by pretreatment with 0.013 g/g of oxalic acid, and the amount of furfural produced by decomposition of xylose was 2~3 times higher than the amount of 5-HMF produced by decomposition of glucose. All the hydrolysates contained more than $5g/{\ell}$ of total phenols considered as the degradation product of lignin. Therefore, by analyzing the amount of fermentable sugars and fermentation inhibitors in the hydrolysate, and producing ethanol from SSF of solid fraction of the pretreated sample, the biomass pretreated with 0.037 g/g of oxalic acid for 20 minutes at $160^{\circ}C$ can be expected to produce the most ethanol.

• The Korean Journal of Mycology
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• v.41 no.3
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• pp.192-196
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• 2013

Fungal development is largely affected by many environmental factors. In a model filamentous fungus Aspergillus nidulans, asexual development is promoted by exposure of light, presence of salt and non-fermentable sugars. In other hand, sexual development is largely induced by absence of light, fermentable sugars and hypoxic condition. Also, some important genes including veA and nsdD play positive roles in activating sexual development. Here, we reported that the effect of high concentration of $CO_2$ on developmental decision in A. nidulans. When wild-type $veA^+$ strain was cultured in normal condition, sexual and asexual development occurred in balanced manner. However, high concentration of $CO_2$ (~5%) strongly activated sexual development and inhibited asexual development. Furthermore, this $CO_2$ effect was controlled by the veA or nsdD gene. High $CO_2$ culture of $veA^-$ or $nsdD^-$ mutant didn't activate sexual development, suggesting that the activation of sexual development induced by high $CO_2$ cannot overcome the genetic requirement of sexual development such as veA or nsdD. Since 5% $CO_2$ is an important condition for human pathogenic fungi for surviving and adapting in human body, this developmental pattern of A. nidulans affected by $CO_2$ concentration may provide interesting clues for comparative study with human fungal pathogens including Aspergillus fumigatus.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.235-238
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• 2008

We examined butanol fermentation by Clostridium beijerinckii NCIMB 8052 using various hydrolyzates obtained from rice bran which is one of the most abundant agricultural by-products in Korea and Japan. In order to increase the amount of fermentable sugars in the hydrolyzates of rice bran, various hydrolysis procedures were applied. Total eight different hydrolyzates were prepared using rice bran (RB) and defatted rice bran (DRB) with enzyme or acid treatment and both. Each hydrolyzate was evaluated in terms of total sugar concentration and butanol production after fermentation by C. beijerinckii NCIMB 8052. Acid treatment yielded more sugar than enzyme treatment and combined treatment with enzyme and acid yielded even more sugars as compared to single treatment with enzyme or acid. As a result, the highest sugar concentration (33 g/L) was observed from the hydrolyzate from DRB (100 g/L) with combined treatment using enzyme and acid. Prior to perform fermentation of the hydrolyzates, we examined the effect of P2 solution containing yeast extract, buffer, minerals, and vitamins on production of butanol during the fermentation. Fermentation of the hydrolyzates with or without additionof P2 was performed using C. beijerinckii NCIMB 8052 in a 1 L anaerobic bioreactor. Although the hydrolyzates RB were able to support growth and butanol production, addition of P2 solution into the hydrolyzates significantly improved cell growth and butanol production. Highest butanol production (12.24 g/L) was observed from the hydrolyzate of DRB with acid and enzyme treatment after supplementation of P2 solution.

• Journal of Microbiology and Biotechnology
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• v.19 no.5
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• pp.482-490
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• 2009

We examined butanol fermentation by Clostridium beijerinckii NCIMB 8052 using various hydrolyzates obtained from rice bran, which is one of the most abundant agricultural by-products in Korea and Japan. In order to increase the amount of fermentable sugars in the hydrolyzates of rice bran, various hydrolysis procedures were applied. Eight different hydrolyzates were prepared using rice bran (RB) and defatted rice bran (DRB) with enzyme or acid treatment or both. Each hydrolyzate was evaluated in terms of total sugar concentration and butanol production after fermentation by C. beijerinckii NCIMB 8052. Acid treatment yielded more sugar than enzyme treatment, and combined treatment with enzyme and acid yielded even more sugars as compared with single treatment with enzyme or acid. As a result, the highest sugar concentration (33 g/l) was observed from the hydrolyzate from DRB (100 g/l) with combined treatment using enzyme and acid. Prior to fermentation of the hydrolyzates, we examined the effect of P2 solution containing yeast extract, buffer, minerals, and vitamins on production of butanol during the fermentation. Fermentation of the hydrolyzates with or without addition of P2 was performed using C. beijerinckii NCIMB 8052 in a 1-1 anaerobic bioreactor. Although the RB hydrolyzates were able to support growth and butanol production, addition of P2 solution into the hydrolyzates significantly improved cell growth and butanol production. The highest butanol production (12.24 g/l) was observed from the hydrolyzate of DRB with acid and enzyme treatment after supplementation of P2 solution.

• The Korean Journal of Food And Nutrition
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• v.10 no.3
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• pp.365-369
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• 1997

Glutinous rice Sikhye was fermented by Saccharomyces cerevisiae for 10 day at 29$^{\circ}C$. Fermentable sugars such as maltose and maltotriose in glutinous rice Sikhye were converted into ethanol by the yeast, but limit dextrin was remained after the fermentation. fermentation rate of sugars in glutinous rice Sikhye was lower than that in rice Sikhye. Glutinous rice Sikhye wine was found to contain 7.3% of limit dextrin, 3.6% of ethanol, 0.35$\mu$mol/ml of amino acid, 100$\mu\textrm{g}$/ml of protein, and the acidity of the Sikhye showed 3.2, respectively, and its pH was 3.23. Limit dextrin in glutinous rice Sikhye wine showed both signal of $\alpha$-1, 4- and $\alpha$-1,6- glucisidic linkage with its estimation ratio of 5.6:1 by 1H-NMR analysis. The taste of rice Sikhye wine was similar that of wine.