• KSBB Journal
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• 제16권5호
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• pp.446-451
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• 2001

신문지와 같은 폐지지 적합한 전처리 방법을 조사하였다. 조사방법은 전처리 후 기질의 효소 가수분해에 영향을 미칠수 있는 인자, 즉 회분의 양, 기질 크기의 잉크의 유무에 따른 효소 당화율을 측정하였다. 이 세 인자 중 잉크가 효소당화율에 미치는 영향이 가장 커서 잉크를 제거하는 방향으로 전처리 방법을 고안하였다. 먼저 섬유성 기질에서 성능이 입증된 percolation반응기에 의한 전처리 방법을 사용하였다. 그러나 17$0^{\circ}C$에서 전처리된 기질은 잉크가 거의 제거되지 않앗고 효소 당화율도 전처리하지 않은 기질보다 더 낮았다. 그래서 10$0^{\circ}C$이하의 낮은 온도에서 회분식 반응기를 사용하는 방법을 연구했는데 암모니아에 과산화수소를 첨가하여 진탕교반시키는 방법이 가장 효과적이었다. 이 방법의 효소 당화율은 전처리하지 않은 기질보다 약 20% 증가한 85%이어서 신문지와 같은 폐지의 전처리에 아주 효과적이었음을 알수 있었다. 이와 같은 높은 당화율은 암모니아에 첨가한 과산화수소가 잉크제거와 기질을 팽윤시키는 작용을 하기 때문이라고 생각된다.

• Korean Chemical Engineering Research
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• 제51권3호
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• pp.303-307
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• 2013

이 연구는 목질계 바이오매스에 대한 알칼리 용액의 침지와 침출 전처리의 효능을 비교한다. 볏짚과 보리짚과 같은 다양한 바이오매스는 수산화나트륨 용액, 수산화칼륨 용액, 암모니아수 그리고 탄산나트륨 용액에 의해 침지 공정으로 수행되었다. 암모니아수에 의해 전처리된 볏짚과 보리짚의 효소 소화율은 80% 이상으로 나타났다. 전처리된 유칼립투스 부산물, 낙엽송 그리고 리기다 소나무의 효소 소화율은 상대적으로 낮은 범위로 나왔다. 하지만 전처리된 유칼립투스 부산물은 초기 바이오매스에 비해 효소 소화율이 약 5배 증가되었다. 또한 침출 공정으로 전처리된 유칼립투스 부산물의 효소 소화율은 약 12배가 증가되는 것을 확인하였다.

• KSBB Journal
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• 제28권1호
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• pp.48-53
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• 2013

Pretreatment of wastepaper using aqueous glycerol was investigated to enhance the enzymatic hydrolysis. The effects of four factors (solid/liquid ratio, glycerol concentration, acid concentration, and reaction time) on the dissolution yield, the removal of cellulose, hemicellulose and lignin, and the enzymatic digestibility were examined at $150^{\circ}C$. The 1/8 of solid/liquid was determined to perform the reaction uniformly, and the 93% of glycerol concentration was found to be a minimum concentration to conduct the reaction under atmospheric pressure. Also, it was found that the acid concentration and reaction time were strongly related to the dissolution yield and the removal of cellulose, hemicellulose and lignin, but moderately to the enzymatic digestibility. At an optimum condition of $150^{\circ}C$, 1 h and 1% acid concentration, 56% and 49% of hemicellulose and lignin, respectively, were removed, while only 4% of cellulose was removed. The enzymatic digestibility at this condition was 86%, meaning that 83% of the glucan present in the initial substrate was converted to glucose. Compared to glycerol with ethylene glycol as a pretreatment solvent, glycerol is much cheaper than ethylene glycol, but ethylene glycol is superior to glycerol in delignification.

• KSBB Journal
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• 제29권3호
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• pp.193-198
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• 2014

Pretreatment of wastepaper using aqueous glycerol under high pressure was studied to enhance the enzymatic hydrolysis. The pretreatment was conducted over a wide range of conditions including temperatures of $150{\sim}170^{\circ}C$, sulfuric acid concentrations of 0.5~1.5%, and reaction times of 30~90 minutes. After the effect of glycerol concentration on the pretreatment performance was investigated, 70% glycerol was selected. As glycerol concentration was increased, higher digestibility was achieved due to higher lignin removal. The optimum condition was found to be around $160^{\circ}C$, 1%, and 60 minutes. At this condition, 60% and 35% of hemicellulose and lignin, respectively, were removed, while only 5% of cellulose was lost. The enzymatic digestibility was 76%, meaning that 73% of the glucan present in the initial substrate was recovered as glucose after enzymatic hydrolysis. Also, it was found that the temperature and acid concentration than the reaction time were more strongly related to the compositional removals and enzymatic digestibility.

• Journal of the Korean Wood Science and Technology
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• 제38권2호
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• pp.149-158
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• 2010

Organosolv pretreatments which utilized sulfuric acid, sodium hydroxide and ammonia as catalysts were conducted to screen the effective catalyst for organosolv pretreatment of Liriodendron tulipifera. The enzymatic hydrolysis was achieved effectively with sulfuric acid (74.2%) and sodium hydroxide (63.7%). They were thus considered as effective catalysts for organosolv pretreatment of L. tulipifera. The organosolv pretreatments with sulfuric acid and sodium hydroxide showed a different behavior on the reaction mechanism. The pretreatment with sulfuric acid increased the biomass roughness and pore numbers. On the other hand, the pretreatment with sodium hydroxide enhanced the surface area due to the size reduction and minor defiberization which were caused by hemicellulose degradation at an initial stage and more defiberization by lignin degradation at a later stage. The organosolv pretreatment with sodium hydroxide was performed at several different conditions to evaluate effectiveness of sodium hydroxide as a catalyst for organosolv pretreatment. According to the results of enzymatic digestibility, the changes of chemical composition and the morphological analysis of pretreated biomass, it was suggested that the pretreatment time impacted primarily on enzymatic hydrolysis. Increase in surface area during the pretreatment was a major cause for improvement in enzymatic digestibility when sodium hydroxide was used as a catalyst.

• Asian-Australasian Journal of Animal Sciences
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• 제14권3호
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• pp.321-325
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• 2001

Two experiments were conducted to examine the degradation rates of 4 tropical legume forages in rumen and intestine of Kedah-Kelantan (KK) cattle. Three KK cattle, averaging $173{\pm}17.15kg$ each fitted with a permanent ruminal and a T-shaped duodenal cannulae were used. The cattle were fed a maintenance diet (1% DM of their body weight) composing of 60% oil palm frond (OPF) pellet and 40% of a legume mixture of Arachis pintoi (AP) and Leucaena throughout the study. The overall DM and CP degradabilities in the rumen for Gliricidia sepium (GS) and AP were significantly higher than those for Leucaena leucocephala-Bahru (LB) and Leucaena leucocephala-Rendang (LR). This implies that LB and LR would have higher dietary protein flows into the intestine for the more efficient enzymatic digestion. However, the results of the present study suggested only limited proportions of the ruminal undegraded protein in the Leucaenas were digested in the intestine.

• Asian-Australasian Journal of Animal Sciences
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• 제16권1호
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• pp.83-87
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• 2003

The study evaluates the enzymatic dry matter (DM) degradability and water holding capacity of leaf and stem fractions of orchardgrass (Dactylis glomerata L.) at different growth stages with or without the presence of surfactant Tween 80. While Tween 80 significantly (p<0.05) increased water and enzyme holding capacities in the leaf blades fraction, less was observed in the fraction of leaf sheath and stem of orchardgrass. The enzyme holding capacity in the leaves was also altered more than that for water holding capacity. This resulted in the increased rate and extent of enzymatic hydrolysis of the leaf blade fractions at two growth stages, whereas little was with leaf sheath and stem fractions. It was also observed that at 0.005% concentrations of Tween 80 the enzymatic DM degradability of young leaf blades was higher (p<0.05) by 20-30% compared to that of the control, as well as for water and enzyme holding capacity. For matured leaf blades the DM degradability were increased with over 0.01% concentrations of the surfactant, but the increase was less than leaf blades of young orchardgrass. This result suggests the possibility of using the surfactant Tween 80 to improve forage digestibility in the rumen.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.218-230
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• 2016

The effect of steam explosion coupled with alkali (1% sodium hydroxide, 1% potassium hydroxide and 15% sodium carbonate) or organosolv solvent (85% methanol, 70% ethanol and dioxane) on the production of sugar, changes in the chemical composition of M. sinensis were evaluated. The steam explosion coupled with 1% potassium hydroxide and dioxane were better as compared with other treatments based on the removals of acid insoluble lignin, and about 89.0% and 85.4%. Enzymatic hydrolysis of steam explosion with 1% potassium hydroxide and dioxane treated M. sinensis, gave a 98.0% and 96.5% of glucose conversion, respectively. These results suggested that pretreatment of M. sinensis with either potassium hydroxide or dioxane could be a promising pretreatment method for glucose production.

• Asian-Australasian Journal of Animal Sciences
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• 제29권8호
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• pp.1159-1165
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• 2016

The nutritional value of feed proteins and their utilization by livestock are related not only to the chemical composition but also to the structure of feed proteins, but few studies thus far have investigated the relationship between the structure of feed proteins and their solubility as well as digestibility in monogastric animals. To address this question we analyzed soybean meal, fish meal, corn distiller's dried grains with solubles, corn gluten meal, and feather meal by Fourier transform infrared (FTIR) spectroscopy to determine the protein molecular spectral band characteristics for amides I and II as well as ${\alpha}$-helices and ${\beta}$-sheets and their ratios. Protein solubility and in vitro digestibility were measured with the Kjeldahl method using 0.2% KOH solution and the pepsin-pancreatin two-step enzymatic method, respectively. We found that all measured spectral band intensities (height and area) of feed proteins were correlated with their the in vitro digestibility and solubility ($p{\leq}0.003$); moreover, the relatively quantitative amounts of ${\alpha}$-helices, random coils, and ${\alpha}$-helix to ${\beta}$-sheet ratio in protein secondary structures were positively correlated with protein in vitro digestibility and solubility ($p{\leq}0.004$). On the other hand, the percentage of ${\beta}$-sheet structures was negatively correlated with protein in vitro digestibility (p<0.001) and solubility (p = 0.002). These results demonstrate that the molecular structure characteristics of feed proteins are closely related to their in vitro digestibility at 28 h and solubility. Furthermore, the ${\alpha}$-helix-to-${\beta}$-sheet ratio can be used to predict the nutritional value of feed proteins.

• 한국식생활문화학회지
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• 제12권4호
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• pp.375-382
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• 1997

The establishment of optimal producing condition for rice-based infant foods using modified rice powder was attempted. The modification of rice powder was prepared by microwave heating as well as partial enzymatic hydrolysis. Not only thermal treatment but also enzymatic hydrolysis on rice powder increased D.E. value from 1.25 to 3.81. The water binding capacity, swelling power, solubility, digestibility by ${\alpha}-amylase$, light transparency, and paste clarity of the modified rice powder compared to unmodified rice powder were increased from 107% to 249%, from 7.80 to 42.52, from 0.04% to 0.89ft, from 9.19% to 23.01, from 33% to 42%, and from 2.2% to 3.9%, respectively. On the other hand, gelatinization temperature, apparent viscosity, and degree of retrogradation of modified rice powder showed negative correlation with D.E. value. The 「results suggested that the thermal and enzymatic treatment on rice powder improved the physicochemical properties of rice based infant food by enhancing carbohydrate absorptionability and lowering the viscosity and opacity.