• Culinary science and hospitality research
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• v.21 no.1
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• pp.30-41
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• 2015

This study was prepared by varying the type of barley sikhye to promote the use of barley. to learn the quality characteristics of traditional beverage sikhye, sikhyes were made out of different kinds of barley such as amethyst barley, black naked barley, tetrastichum barley, tetrastichum waxy barley, naked barley and naked waxy barley. The result of the study is as following. Regarding the length/width ratio of barley grain, black naked barley was the biggest; while amethyst barley was the smallest. Moisture content of barley grain was in the range of 54.96~71.74%. The saccharification liquid pH was in the range of 5.40~5.63 and the soluble solid content was in the range of 15.37~18.73 brix %. The saccharification liquid of sikhye made of tetrastichum waxy barley had the highest soluble solid content; while the saccharification liquid of sikhye made of black naked barley had the lowest soluble solid content. Reducing sugar was in the range of 4.35~7.42 mg/ 100 g; at which tetrastichum waxy barley sikhye had the highest reducing sugar while black naked barley sikhye had the lowest reducing sugar. The result of reducing sugar was similar to the result of soluble solid content. Black naked barley had low Lightness, redness and yellowness in its cooked rice grain and saccharification liquid. The result of barley sikhye characteristics was as following. Black naked barley had the strongest fullness while tetrastichum waxy barley had the weakest fullness. Black naked barley had strong feeling after swallowing the barley rice grain; while tetrastichum waxy barley had weak feeling after swallowing the barley rice grain. The result of feeling after swallowing the barley rice grain had correlation with fullness. The result of preference test was as following. naked waxy barley sikhye and naked barley sikhye had best outlook. In the smell, amethyst barley sikhye was the best. regarding texture, naked barley sikhye and naked waxy barley sikhye had high preference. In overall preference, naked barley sikhye was the best. Like above, there were differences in quality in sikhyes dependent on the variety of barley. In particular, tetrastichum waxy barley and naked barley will be able to increase the amount of sweetness without malt production during sikhye.

• Microbiology and Biotechnology Letters
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• v.44 no.2
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• pp.145-149
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• 2016

Thermal acid hydrolysis pretreatment of Kappaphycus alvarezii was carried out with 12% (w/v) seaweed slurry and 180 mM H₂SO₄ at 140°C for 5 min. Utility of the thermotolerant yeast Kluyveromyces marxianus KCTC7150 was evaluated with respect to cell growth and ethanol fermentation at 40°C was close to optimal for enzymatic hydrolysis. This could lead to the integration of both the saccharification and fermentation processes. The levels of ethanol production by simultaneous saccharification and fermentation (SSF) with non-adapted and adapted K. marxianus KCTC7150 were 9.1 g/l with an ethanol yield (Y_EtOH) of 0.24 and 10.2 g/l with an ethanol yield (Y_EtOH) of 0.27 at 156 h, respectively. The two-phase SSF process was employed in this study to improve the efficiency of ethanol fermentation. Adapted K. marxianus KCTC7150 using the two-phase SSF process produced 13.5 g/l with an ethanol yield (Y_EtOH) of 0.35 at 96 h. Development of the two-phase SSF process could enhance the overall ethanol fermentation yields of the seaweed K. alvarezii.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.439-444
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• 2003

The major factors related in enzymatic hydrolysis of food waste using cellulolytic enzymes of Trichoderma harzianum FJ1 were optimized by response surface analysis. The factors largely affecting to the reducing sugar concentration and enzymatic saccharification rate of food waste such as substrate concentration ($X_1$, %), enzyme concentration ($X_2$, U/ml), and reaction time ($X_3$, hr) were employed. A quadratic polynominal expressing the reducing sugar (RS) concentration relating with the above factors was as follows : RS (g/l) = -17.80 + $5.04X_1$ + $51.37X_2$ + $1.21X_3$ - $0.11X_1\;^2$ - $38.86X_2\;^2$ - $0.03X_3\;^2$ + $1.64X_1X_2$ + $0.04X_1X_3$ - $0.70X_2X_3$ ($R^2$=0.9939). The maximum value of the reducing sugar concentration and saccharification rate were obtained in the conditions of substrate concentration of 18.2%, enzyme concentration of 0.78 U/ml, and reaction time of 19 hr, respectively. The predicated reducing sugar concentration and saccharification rate by the response surface methodology were 95.13 g/l and 47.27%, respectively.

• The Korean Journal of Food And Nutrition
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• v.30 no.6
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• pp.1260-1267
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• 2017

The properties of rice were studied on five rice cultivars (Ilpumbyeo, Samkwang, Goami-4, Dodamssal, and Thai rice), and employed two kinds of saccharification treatment methods (treatment I : rice shape, treatment II: grinding rice shape). Thai rice showed differences in width and length when compared to other cultivars of rice, and the Goami 4 had the lowest thousand-grain weight. The Goami4 and Dodamssal each showed high contents of amylose and resistant starch, and the water absorption rate was close to maximum at 90 minutes as well as the highest level of Goami 4 at all times. The qualities of highest water-binding capacity, solubility and swelling power was most significant in Thai rice. The lowest hardness level of wet rice resulted in the lowest hydration-related characteristics. High amylose content rice, in particular, showed low sugar content and slightly increased sugar content as the saccharification process improved (treatment II). On the other hand, high amylose cultivars had the same high degree of hardness as boiled rice. From these results, the Dodamssal was found to have the lowest viscosity at all temperatures but highest viscosity during the saccharification process, suggesting it may be successfully implemented as a thickener in rice beverage processing. The purpose of this study was to attempt to provide basic data on the development of rice beverage manufacturing technology, based upon the quality characteristics related to beverage processing of rice cultivars.

• Journal of the Korean Wood Science and Technology
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• v.15 no.4
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• pp.18-25
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• 1987

The cellulolytic activities of Aspergillus fumigatus KC-1 was investigated, which showed the most active producer of cellulase among the 256 strains of cellulose-decomposing microorganisms screened in our laboratory. All the examined cellulolytic activities (filter paper-, Avicel-, cotton-, CMC-, salicin- and xylansaccharifying activity) in a culture of A. fumigatus KC-1 grown on 1% popular sawdust pretreated with peroxide alkaline reached a maximum within 4-5 days. The optimum pH and temperature for the enzymatic activity was found to be pH 4.5 and $60^{\circ}C$ respectively. The sawdust of poplar wood delignified with 1% NaOH and 20% peracetic acid succesively recorded the highest hydrolysis rate in the tests of enzymatic saccharification. The major end product of hydrolysis of poplar wood with the cellulolytic enzymes obtained from A. fumigatus KC-1 was glucose with small amount of cellobiose and xylose. It can be concluded from these results that A. fumigatus KC-1 is an advantagous source of a cellulase that is capable of hydrolyzing cellulose to glucose rapidly. The influence of degree of delignification, substrate size and its concentration on the rate of hydrolysis of poplar wood was also discussed.

• Journal of Microbiology and Biotechnology
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• v.28 no.4
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• pp.588-596
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• 2018

An endo-${\beta}$-1,4-glucanase gene, cel9K, was cloned using the shot-gun method from Paenibacillus sp. X4, which was isolated from alpine soil. The gene was 2,994 bp in length, encoding a protein of 997 amino acid residues with a predicted signal peptide composed of 32 amino acid residues. Cel9K was a multimodular enzyme, and the molecular mass and theoretical pI of the mature Cel9K were 103.5 kDa and 4.81, respectively. Cel9K contains the GGxxDAGD, PHHR, GAxxGG, YxDDI, and EVxxDYN motifs found in most glycoside hydrolase family 9 (GH9) members. The protein sequence showed the highest similarity (88%) with the cellulase of Bacillus sp. BP23 in comparison with the enzymes with reported properties. The enzyme was purified by chromatography using HiTrap Q, CHT-II, and HiTrap Butyl HP. Using SDS-PAGE/activity staining, the molecular mass of Cel9K was estimated to be 93 kDa, which is a truncated form produced by the proteolytic cleavage of its C-terminus. Cel9K was optimally active at pH 5.5 and $50^{\circ}C$ and showed a half-life of 59.2 min at $50^{\circ}C$. The CMCase activity was increased to more than 150% in the presence of 2 mM $Na^+$, $K^+$, and $Ba^{2+}$, but decreased significantly to less than 50% by $Mn^{2+}$ and $Co^{2+}$. The addition of Cel9K to a commercial enzyme set (Celluclast 1.5L + Novozym 188) increased the saccharification of the pretreated reed and rice straw powders by 30.4% and 15.9%, respectively. The results suggest that Cel9K can be used to enhance the enzymatic conversion of lignocellulosic biomass to reducing sugars as an additive.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.101-110
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• 2011

The experiment was conducted to evaluate the different NaOH pretreatment concentrations (0.25%, 0.50%, 0.75%, and 1.00%) on enzymatic saccharification (with cellulase, and ${\beta}$-glucosidase) and fermentation (by Saccharomyces cerevisiaeKCCM 11304) for bioethanol production from rice straw and rice husk. Pretreatment of rice straw and rice husk were conducted under both natural and powder state to observe the potentiality of the biomass condition (natural and powder state). In this study, glucose and ethanol production were increased with the increase of NaOH percentage for both rice straw and rice husk (natural and powder state). For rice straw, the highest amount of glucose was obtained in 1.00% NaOH pretreatment (0.81 g $g^{-1}$ in a natural, and 0.63 g $g^{-1}$ in a powder state pretreatment). Similarly, for rice husk, the highest amount of glucose was obtained in 1.00% NaOH pretreatment (0.47 g $g^{-1}$ in a natural, and 0.46 g $g^{-1}$ in a powder state pretreatment). However, 0.75% NaOH pretreatment resulted in glucose yield near about 1.00% NaOH pretreatment for both rice straw and rice husk (natural and powder state). On the other hand, for rice straw, the highest amount of ethanol was obtained in 1.00% NaOH pretreatment (0.36 g $g^{-1}$ in a natural, and 0.31 g $g^{-1}$ in a powder state pretreatment). In addition, for rice husk, the highest amount of ethanol was also obtained in 1.00% NaOH pretreatment (0.24 g $g^{-1}$ in a natural, and 0.23 g $g^{-1}$ in a powder state pretreatment). Moreover, 0.75% NaOH pretreatment resulted in ethanol yield near about 1.00% NaOH pretreatment for both rice straw and rice husk (natural and powder state). It was confirmed that higher amount of NaOH use is cost effective. Moreover, higher amount of glucose and ethanol was observed when powder was prepared after pretreatment. So 0.75% NaOH pretreatment in a natural state is supposed to be suitable for enzymatic saccharification and fermentation for bioethanol production.

• Journal of the Korean Wood Science and Technology
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• v.39 no.1
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• pp.75-85
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• 2011

The main purpose of this study is to evaluate the potential of producing bioethanol from yellow poplar ($Liriodendron$ $tulipifera$) wood chips by oxalic acid pretreatment and to examine the pretreatment conditions by response surface methodology (RSM). Based on $2^3$ factorial design, adjusted variables were reaction temperature ($^{\circ}C$), residence time (min), and acid loading (g/g), and a series of distinct 15 experimental conditions was organized with duplication at central point (total 16 performances). After pretreatment, simultaneous saccharification and fermentation (SSF) was subjected on solid fraction with yeast strain $Pichia$ $stipitis$. Maximum ethanol yields of the most samples were measured at 72 hours and applied to RSM as a dependent variable. 9.7 g/${\ell}$ of ethanol was produced from the solid pretreated at $180^{\circ}C$ for 40 min with 0.013 g/g of oxalic acid loading. According to the response surface methodology, it was determined that the temperature is the most governing factor via statistic analysis.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.89-95
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• 2009

Because of high contents of cellulose (~37 wt%) and hemicellulose (~17%), rice straw seems to be a potential lignocellulosic biomass for production of bioethanol. In this study, Ammonia Recycled Percolation (ARP) pretreatment of rice straw was extensively investigated. In particular, the experimental study included the effects of temperature, reaction time and concentration of ammonia on compositions and enzymatic digestibility of the resulting solid residues; the ranges of pretreatment conditions were, in turn, $150{\sim}190^{\circ}C$, 10~90 min and 0~20 wt%. Through ARP pretreatment, the lignin content was reduced by as high as ~84% while 20~80% of the hemicellulose was also solubilized. The solid residue resulted from the pretreatment with 15 wt% aqueous ammonia solution at $170^{\circ}C$ for 90 mim showed as high as ~90% of digestibility with 15FPU/g of glucan enzyme loading. Supplement of xylanese to cellulase led to a notable enhancement of digestibility, indicating a discernable inhibitory role of hemicellulose. Simultaneous Saccharification and Fermentation (SSF) and Simultaneous Saccharification and Co-Fermentation (SSCF) were performed to obtain ethanol productions of 13.8 g/L (corresponding to 81% yield) and 15 g/L (corresponding to 89% yield), respectively.

• Culinary science and hospitality research
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• v.19 no.3
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• pp.46-56
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• 2013

This study investigates the quality characteristics of Sikhye, a Korean traditional drink, made with different amounts of Monascus anka rice, or red yeast rice, and the results are as follows. During the saccharification process of red yeast rice, there was not significant change in pH, and its sugar content increased. It revealed that the optimal hours of saccharification for making Sikhye were four or five hours, which showed the highest in $^{\circ}Brix$. PH decreased significantly with increasing amounts of red yeast rice, and there was no change in sugar content and reducing sugar. Chromaticity L values decreased with increasing amounts of red yeast rice, and a value, b value and the turbidity increased. DPPH free radical scavenging activity of the samples showed significant differences in the samples with high scores as the amounts of red yeast rice increased. As a result of measuring the total microorganism number of the sample stored at $4^{\circ}C$, storability was improved with increasing amounts of red yeast rice. Preference was high in the order of 40%, 50%, 30%, 20%, 0%, and 10%, and the optimal amount of red yeast rice was less than 40-50%. Adding red yeast rice showed high scores in the sensory test, showing red color in Sikhye. In addition, its antioxidative activity effect and microbial growth inhibitory activity were considered to improve storability and preference.