• Journal of the Korean Wood Science and Technology
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• 제18권4호
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• pp.18-25
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• 1990

As polysaccharides in lignocellulosic materials are encrusted with aromatic lignin molecules and have high crystallinity, these require pretreatment to improve their digestability by cellulolytic enzymes. Though a number of pretreatment methods have been proposed, the steam explosion process is evaluated as a promising method. This study was performed to investigate the effect of delignification treatment by alkali, methanol and the others on the enzymatic hydrolysis. Delignification treatment resulted in great increase rate in enzymatic hydrolysis. Concerning to the effect of delignication reagents on the enzymatic hydrolysis, methanol treatment was more effective than alkali in the case of oak wood. In pine wood, the delignification did not showed any significant enhancement of hydrolysis rate. Complete delignification by Alkali-Oxygen. Alkali treatment showed high saccharification rate of 99.5%.

• Journal of the Korean Wood Science and Technology
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• 제22권1호
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• pp.34-39
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• 1994

Effects of Mg-base acid sulfite and Mg- or Na-base bisulfite on pine bark cooking were examined. In the presence of 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid. However, the delignification could not be achieved by 50 % or more under these cooking conditions. When cooked with 50~65 % free acid and at 155~165 $^{\circ}C$, the rate of cooking and delignification was remarkably improved. Thus, the bark was delignified up to 73 % when cooked for 2 hours in the presence of 50 % free acid and 24 % total acid. Na-base bisulfite was slightly more effective than Mg-base bisulfite for cooking, giving 76 % delignification of pine bark. However, there was no significant difference in selectivity of delignification between Na- and Mg-base bisulfite cooking.

• 펄프종이기술
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• 제39권5호
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• pp.7-11
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• 2007

Kraft pulping of Trema orientalis (Nalita) was studied in order to find kinetic data for delignification. Pulping runs were carried out in the temperature range of $160-180\;^{\circ}C$ under constant and well-defined conditions. The delignification was found to be first order with respect to residual lignin and was chemically controlled. The rate of delignification reaction was increased 1.11-1.23 for $10\;^{\circ}C$ temperature increase in the range of $160-180\;^{\circ}C$ range. A mean value of 93% of lignin was removed at the transition between bulk and residual delignification. The influence of cooking temperature on the rate constant was expressed by an Arrhenius-type equation. The obtained activation energy of the delignification reaction was 6,164 cal/mol. The transition point between bulk and residual phase was shifted to lower lignin and carbohydrate yield with the increase of temperature.

• Journal of the Korean Wood Science and Technology
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• 제20권3호
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• pp.11-20
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• 1992

Steam explosion is one of the most effective pretreatment for fractionating wood. This leads to the total utilization of wood basic components; cellulose, hemicellulose and lignin. The amount of sugar and lignin extracted with the hot water method was very low. The lignin content of residues after extraction with using a sodium hydroxide treatment, increased delignification of carbohydrate as the concentration of alkali was increased. Oak, pretreated with steam exploded at 25kg/$cm^2$ for 6 min. then 1% alkali for 2hrs. showed a delignification rate up to 95%. A sodium chlorite treatment of steam exploded pine and oak also afforded a high deligninfication effect. Pine, treated 10% sodium chlorite for 2hrs. showed high delignification. However, by using a sodium hydroxide treatment, a 2% retreatment for Ihr. after a 2% for 2hrs. afforded remarkable delignification effect on exploded wood at 30kg/$cm^2$ for 9min. and at 35kg/$cm^2$ for 3-6min. In oak, an initial 2hrs. treatment of 2% sodium chlorite was followed by a second 2hrs. treatment at 10%. This showed a delignification rate of 96%.

• Journal of the Korean Wood Science and Technology
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• 제27권2호
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• pp.46-52
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• 1999

소나무 수피를 알칼리성 아황산염-안트라퀴논(AQ) 증해하고, 고도로 탐리그닌 시킬 수 있는 조건을 검토하였다. 수피의 탈리그닌은 약알칼리성 아황산염 증해 조건에서보다 알칼성 아황산염 증해 조건에서 용이하였다. 그러나 알칼리성 아황산염 증해조건에서도 수피리그닌의 90%이상을 용출시키기는 어려웠다. AQ는 알칼리성 아황산염 증해 조건에서 수피의 증해 및 탈리그닌 속도를 현저하게 향상 시킬 뿐만 아니라 탈리그닌 선택성도 개선시켰다. 결과적으로 수피에 대하여 0.2% AQ의 첨가로 90%이상의 탈리그닌이 가능하였다. 수피 알칼리성 아황산염-AQ증해시 증해온도 및 NaOH의 투여량은 탈리그닌 선택성에 대해서 큰 영향을 미치지 못하였다. 그러나 $Na_2SO_3$ 투여량은 수피의 탈리그닌 선택성에 큰 영향을 미쳐 $Na_2O$로서 30%의 $Na_2SO_3$ 투여조건에서 가장 양호한 탈리그닌을 나타내었다.

• Journal of the Korean Wood Science and Technology
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• 제20권1호
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• pp.60-71
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• 1992

To investigate the delignification behaviour in solvolysis pulping process, Populus alba ${\times}$ glandulosa H. and Pinus Kuraiensis S. et Z. were cooked with p-cresol and vater solvent(2:8, 5:5, 8:2 v/v) at $175^{\circ}C$ for 9 cooking time levels(20, 40, 60, 80, 100, 120, 140, 160, 180, min). Pulp yield, residual lignin content, de lignification rate, decarborhydration rate were determined. Delignification behaviours were analyzed by TEM. 1. The p-cresol-water solvent cooking of P. alba ${\times}$ glandulosa showed good delignification at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v), while the cooking of P. koraiensis with the p-cresol and water mixture ratio of 5:5 was no good. 2. P. alba ${\times}$ glandulosa showed three step-delignification phenomena at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v) anti 5:5(v/v). But P. koraiensis showed a first order delignification reaction at the same mixture ratio of p-cresol and water solvent system. 3. In TEM micrograph obtained for the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), the partial delignification of the cell corner of P. alba ${\times}$ glandulosa and P. koraiensis were observed at 60min. of cooking time. Complete delignification at the cell corner of P. alba ${\times}$ glandulosa was observed at 160min. and that of P. koraiensis was observed of 180min. of cooking time. 4. In optical microscopic observation, fiber separation of P. alba ${\times}$ glandulosa occured at 120min. and that of P. koraiensis began at 140min. of cooking time. 5. At the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), middle layer on secondary wall($S_2$) and cell corner of P. alba ${\times}$ glandulosa were more selectively delignified than primary wall(P) and outer layer on secondary wall($S_1$). However P. koraiensis did not showed any difference in delignification between cell wall layers and cell corner.

• Journal of the Korean Wood Science and Technology
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• 제22권1호
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• pp.28-33
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• 1994

The chemical compositions of pine bark from mechanical pulp industry were determined, and effect of Ca base acid sulfite on bark cooking was investigated under various conditions. The pine bark was composed of 39.5 % alkali extractives, 50.3 % lignin, and a small amount of carbohydrate. The contents of alkali extractives and lignin were remarkably higher than those of pine wood. The bark was composed of high content of arabinose and xylose, while the wood was composed of high content of mannose. When pine bark was cooked with 75 % free acid at 145 $^{\circ}C$, the rate of cooking and delignification was improved with the increase of total acid, but it was very difficult to delignify the bark by 50 % and over under these conditions. In the presence of 60~65 % free acid and at 155~165 $^{\circ}C$, initial cooking rate, delignification, and delignification selectivity were considerably increased, but condensation reaction of lignin was considerable at the end of cooking. Therefore, it was shown that pine bark was very difficult to delignify by the Ca-base acid sulfite cooking.

• 펄프종이기술
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• 제47권4호
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• pp.21-29
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• 2015

In this study, the feasibility of utilizing wood chips from pitch pine (Pinus rigida) was evaluated for bioethanol production by an organosolv pretreatment and enzymatic saccharification. When wood chips from pitch wood were pretreated with 75% (v/v) ethanol and 1.7% sulfuric acid as a catalyst at H-factor 2000, average pulp yield was 43.3%, which pretreated wood fibers showed higher glucan (55.8%) and lower lignin (12.2%) contents than untreated control (43.9% glucan and 27.8% lignin). After enzymatic saccharification, the organosolv pulps with 56.2% delignification rate reached above 97% conversion rate of cellulose to glucose. These results indicated that increasing the delignification rate causes micro pores on the surface of organosolv pulps resulting in improved the accessibility of enzyme onto the substrate. Moreover, it was in agreement with the SEM examination of wood fibers.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.285-290
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• 2006

As an alternative method to solve air pollution problem and difficulty of pulp bleaching of kraft pulping process, NaOH-Urea pulping was applied. The properties of NaOH-Urea pulp were compared to those of NaOH and kraft pulps. Addition of urea in low alkali charges retarded delignification rate compared to NaOH pulping. But, in high alkali application, delignification was significantly enhanced not from the addition of urea but from the high alkalinity. It was disclosed that urea did not participate on delignification reaction by the experiment using lignin model compound. Compared to paper strengths at the same level of sheet density, NaOH-Urea pulp gave as almost same breaking length and tensile index as those of kraft pulp. Especially tensile energy absorption and burst index were higher than those of kraft pulp.

• 한국산림과학회지
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• 제56권1호
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• pp.26-50
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• 1982

본(本) 연구(硏究)에서는 효소(酵素) 알칼리 증해(蒸解)의 리그닌 용출거동(溶出挙動) 파악하기 위(爲)해 잣나무(Pinus koraiensis S. et Z.) 목분(木粉)을 공시(供試)하여 $110^{\circ}C$, $120^{\circ}C$, $130^{\circ}C$, $140^{\circ}C$, 및 $150^{\circ}C$의 5 수준(水準) 온도(溫度)로 60분간(分間) 1단(段) 등온(等溫) 효소(酵素) 알칼리 탈(脱)리그닌 처리(処理)를 행(行)한 후(後), 그 탈(脱)리그닌 반응속도(反応速度), 활성화(活性化)에너지 및 반응시간별(反応時間別) 알칼리와 효소(酵素)의 소비동향(消費動向)을 동역학적(動力學的) 방법(方法)으로 구명(究明)하였다. 그 결과(結果)를 보면 탈(脱)리그닌은 반응초기(反応初期)에 전(全)리그닌 함량(含量)의 2/5가량이 급속(急速)히 용출(溶出)되는 초기(初期) 산화반응(酸化反応)을 나타냈다. 탈(脱)리그닌 반응(反応)의 속도상교(速度常敎)(K)는 반응온도(反応溫度) $150^{\circ}C$의 경우, 소오다법(法)에 비(比)해 3배정도(倍程度) 더 컸다. 본 법(法)의 활성화(活性化)에너지 값은 크라프트나 소오다 펄프법화(法化)보다 1/3정도(程度) 낮은 수준(水準)이었다. 알칼리소비량은 효소(酵素)의 경우와 마찬가지로 반응초기(反応初期)에 총투입량(總投入量)의 1/2가량이 급속히 소모된 후, 완만한 소비협추세(消費趨勢)를 보였다. 탈(脱)리그닌 반응속도(反応速度)는 증해과정중 생성되는 유기산(有機酸) 때문에 pH가 감소됨에 따라 크게 영향을 받았다. 또한 증해용출(蒸解溶出)된 리그닌은 잘 침전(沈澱)되지 않을 만큼 저분자화(低分子化) 됨을 알수 있었다. 리그닌의 메톡실기(基)는 급속히 감소(減少)되는데 반(反)해, 페놀성(性) 하이드록실기(基), 카보닐기(基) 및 카복실기(基)는 증가(增加)추세를 보였다.