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Last Updated :2024/07/25

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Master

Affiliation (Master)

  • Research Faculty of Agriculture　Fundamental AgriScience Research　Forest Science

Affiliation (Master)

  • Research Faculty of Agriculture　Fundamental AgriScience Research　Forest Science

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Profile and Settings

Degree

  • Doctor of Agriculture（The University of Tokyo）
  • Master of Agriculture（The University of Tokyo）

Profile and Settings

  • Name (Japanese)

    Koda

  • Name (Kana)

    Keiichi

  • Name

    200901054860589835

Alternate Names

Achievement

Research Interests

  • carbon cycle   litter   pulping   bleaching   biorefinery   biodegradation   chemical modification   woody biomass   lignin   Wood Chemistry   

Research Areas

  • Life sciences / Wood science / Wood chemistry

Research Experience

  • 2020/07 - Today Hokkaido University Division of Fundamental AgriScience Research, Research Faculty of Agriculture Associate Professor
  • 2015/04 - 2020/06 Hokkaido University Graduate School of Agriculture Research Faculty of Agriculture Lecturer
  • 2011/08 - 2015/03 Hokkaido University Graduate School of Agriculture Research Faculty of Agriculture, Division of Bioresources and Product Science
  • 2007/04 - 2011/07 Hokkaido University Graduate School of Agriculture Research Faculty of Agriculture, Division of Bioresources and Product Science
  • 2006/04 - 2007/03 Hokkaido University Graduate School of Agriculture Research Faculty of Agriculture, Division of Bioresources and Product Science
  • 2000/04 - 2006/03 Hokkaido University

Education

  • 1997/04 - 2000/03  The University of Tokyo  Graduate School of Agricultural and Life Sciences  Biomaterial Sciences
  • 1997/04 - 2000/03  The University of Tokyo  Graduate School of Agricultural and Life Sciences  Division of Biomaterial Sciences (Ph.D. Course)
  • 1995/04 - 1997/03  The University of Tokyo  Graduate School of Agricultural and Life Sciences  Biomaterial Sciences
  • 1995/04 - 1997/03  The University of Tokyo  Graduate School of Agricultural and Life Sciences  Division of Biomaterial Sciences (Ms Course)
  • 1993/04 - 1995/03  The University of Tokyo
  • 1993/04 - 1995/03  The University of Tokyo  Faculty of Agriculture  Division of Forest Products

Committee Memberships

  • 2021/11 - Today   The Lignin Society   Director

Awards

  • 2018/11 リグニン討論会事務局 Excellent oral presentation award, 63th Lignin Symposium
     Assembly of electric double layer capacitor with electrode made from lignin and ionic liquid as an electrolyte 
    受賞者: Nutthira Pakkang;Keiichi Koda;Yasumitsu Uraki
  • 2018/10 日本木材学会北海道支部 2018年度・第16回北の木材科学賞（口頭発表部門）
     電気二重層キャパシタ用セパレータとしてのセルロースナノファイバー強化リグニンポリエステルフィルム 
    受賞者: Shogo Taira;Keiichi Koda;Yasumitsu Uraki
  • 2017/11 日本木材学会北海道支部 2017年度・第15回北の木材科学賞（口頭発表部門）
     リグニン形成におけるヘミセルロースの機能 
    受賞者: 古川貴大;吉永 新;高部圭司;松尾朱実;玉井 裕;幸田圭一;浦木康光
  • 2015/11 Organizing Committee, The 60th Lignin Symposium G-Award, The 60th Lignin Symposium (Oral Presentation)
     Preparation of electric double layer capacitor electrode from several kinds of isolated lignins 
    受賞者: Xiangyu You;Junlei Duan;Keiichi Koda;Yasumitsu Uraki;Tatsuhiko Yamada;Satoshi Kubo参照URL： http://www.agr.hokudai.ac.jp/news/2015/12/post-642.html
  • 2015/11 日本木材学会北海道支部 2015年度・第13回北の木材科学賞（展示発表部門）
     水溶性酢酸セルロースの電界紡糸とコンポジット化 
    受賞者: 鶴原正啓;幸田圭一;浦木康光参照URL： http://www.agr.hokudai.ac.jp/news/2015/12/post-644.html
  • 2015/11 日本木材学会北海道支部 2015年度・第13回北の木材科学賞（口頭発表部門）
     PEGリグニン由来の電気二重層キャパシタ用セパレータの開発 
    受賞者: 久保田 惇;磯崎友史;山田竜彦;幸田圭一;浦木康光参照URL： http://www.agr.hokudai.ac.jp/news/2015/12/post-643.html
  • 2014/11 日本木材学会北海道支部 2014年度・第12回北の木材科学賞（口頭発表部門）
     バイオエタノール生産に有用な両親媒性リグニン誘導体 
    受賞者: 山本陽子;Ningning Cheng;五十嵐圭日子;幸田圭一;浦木康光
  • 2014/03 日本森林学会 日本森林学会学生ポスター賞
     遡上したサケがもたらす窒素の落葉層への滞留 
    受賞者: 福井喬史;宮本敏澄;長坂 有;長坂晶子;幸田圭一;玉井 裕;矢島 崇
  • 2013/11 日本木材学会北海道支部 2013年度・第11回北の木材科学賞（展示発表部門）
     香気成分の定量的分析によるインドネシア産沈香の評価 
    受賞者: 石井貴史;幸田圭一;玉井 裕;Ina Winarni;Maman Turjama;浦木康光
  • 2012/11 日本木材学会北海道支部 2012年度・第10回北の木材科学賞（展示発表部門）
     ミズナラ緑葉に含まれるリグニンの地域間差異 
    受賞者: 川口 新;幸田圭一;宮本敏澄;浦木康光
  • 2012/11 日本木材学会北海道支部 2012年度・第10回北の木材科学賞（口頭発表部門）
     ヒドロキシプロピルセルロースゲルの熱応答性 －架橋剤が及ぼす影響－ 
    受賞者: 神田高志;幸田圭一;浦木康光
  • 2012/06 日本森林技術協会 第二十二回学生森林技術研究論文コンテスト 日本森林技術協会理事長賞
     オゾン酸化によるクラフトリグニンの改質-木質バイオマス系ポリカルボン酸の調製- 
    受賞者: 磯崎友史;主指導教員;幸田圭一;副指導教員;浦木康光
  • 2011/11 日本木材学会北海道支部 2011年度・第9回北の木材科学賞（展示発表部門）
     両親媒性リグニンを用いたAE型セメント分散剤の開発 
    受賞者: 麻生知裕;幸田圭一;山田竜彦;久保智史;中嶋 勇;浦木康光
  • 2011/11 日本木材学会北海道支部 2011年度・第9回北の木材科学賞（口頭発表部門）
     両親媒性リグニンによる酵素糖化の改善 
    受賞者: 及川千皓;イナ・ウィナルニ;幸田圭一;山田竜彦;浦木康光
  • 2010/11 日本木材学会北海道支部 2010年度・第8回北の木材科学賞（口頭発表部門）
     エレクトロスピニング法によるセルロースアセテート・ナノファイバーの調製とその利用 
    受賞者: 冨樫文哉;幸田圭一;浦木康光
  • 2010/07 セルロース学会 セルロース学会第17回香川大会 ポスター賞
     ヘミセルロース吸着ハニカムパターン化セルロースの調製とその利用 
    受賞者: 田崎裕佳;浦木康光;幸田圭一;山本貞明;藪 浩;下村政嗣
  • 2010 Oral Presentation Award at the 42nd annual meeting of Hokkaido Branch, Japan Wood Research Society, Asahikawa, Nov. 9, 2010
  • 2010 Poster Award at the 17th annual meeting of the Cellulose Society of Japan, Kagawa, Jul. 15-16, 2010
  • 2009/11 日本木材学会北海道支部 2009年度・第7回北の木材科学賞（口頭発表部門）
     高界面活性リグニン誘導体の調製とその分散性能の評価 
    受賞者: 本間春海;浦木康光;幸田圭一;久保智史;山田竜彦;松下泰幸;福島和彦
  • 2009 Oral Presentation Award at the 41st annual meeting of Hokkaido Branch, Japan Wood Research Society, Asahikawa, Nov. 9, 2009

Published Papers

  • Linping Wang, Kengo Shigetomi, Keiichi Koda, Aori Gele, Yasumitsu Uraki
    Holzforschung 74 (6) 551 - 558 0018-3830 2020/06/25 [Refereed][Not invited]
     
    Abstract Size exclusion chromatography with multi-angle laser light-scattering detectors was applied for acetylated softwood and hardwood kraft lignins (Ac-SKL and Ac-HKL) and 8-O-4′ type of linear polymeric lignin model (Ac-M-8O4′) to compare their swelling behaviors. The plot of molar mass (MM) vs. retention time for Ac-M-8O4′ was similar to that of polystyrene, which revealed that Ac-M-8O4′ exhibited swelling behavior that was similar to that of polystyrene. However, the MM values of both Ac-KLs were larger than those of polystyrene standards at any retention time. This difference indicated that both Ac-KLs had a more compact structure than those of polystyrene and Ac-M-8O4′. One hypothesis is that the larger MM of both Ac-KLs stems from their branched structures. To verify this hypothesis, the frequency of 5-5′ interunit linkage in lignin samples was determined by 1H NMR after nitrobenzene oxidation. A linear relationship between MM and 5-5′ abundance was observed in the high MM region.
  • Shogo Taira, Masataka Tsuruhara, Ryo Saito, Keiichi Koda, Yasumitsu Uraki, Haruo Konno, Shu Shimamoto
    Cellulose 27 (9) 4991 - 5001 0969-0239 2020/06 [Refereed][Not invited]
  • Nutthira Pakkang, Manish Kumar, Shogo Taira, Keiichi Koda, Kengo Shigetomi, Yasumitsu Uraki
    Holzforschung 74 (6) 577 - 588 0018-3830 2020/05/29 [Refereed][Not invited]
     
    AbstractThis article demonstrates the development of activated carbon fiber electrodes produced from hardwood kraft lignin (HKL) to fabricate electric double layer capacitors (EDLCs) with high energy and power densities using an ionic liquid (IL) electrolyte. A mixture solution of HKL, polyethylene glycol as a sacrificial polymer, and hexamethylenetetramine as a crosslinker in dimethylformamide/acetic acid (6/4) was electrospun, and the obtained fibers were easily thermostabilized, followed by carbonization and steam activation to yield activated carbon fibers (ACFs). The electrochemical performance of EDLCs assembled with the ACFs, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) as an IL electrolyte and a cellulosic separator was insufficient due to the low conductivity of the electrode. The conductivity of the electrode was improved successfully by spraying conductive carbon black (CB) onto the fibers mat during electrospinning. The CB containing electrodes with improved conductivity gave the resulting EDLCs a higher electrochemical performance, with an energy density of 91.5 Wh kg−1 and a power density of 76.2 kW kg−1.
  • Yuu Hasegawa, Mitsunori Mori, Keiichi Koda, Yasumitsu Uraki
    Journal of Wood Chemistry and Technology 40 (1) 1 - 14 0277-3813 2020/01/02 [Refereed][Not invited]
     
    Vapor-phase acetylation of heartwood in Japanese cedar wood (Cryptomeria japonica D. Don) was carried out as a surface acetylation method to elucidate the relationship between the depth of acetylated area and fungal decay resistance. The acetylated wood (VPAW), prepared with acetic anhydride vapor by heating at 80 degrees C for 72 h, indicated a significant fungal decay resistance and dimensional stability in water-soaking test, similar to liquid-phase acetylated wood (LPAW). The VPAW provided more than 15% of the weight percent gain (WPG) up to a depth of 7 mm from the wood surface, while LPAW gave similar to 20% WPG uniformly throughout the wood. However, 24-h vapor-phase acetylation, giving 15% WPG at a depth of 0-2 mm, showed insufficient fungal decay resistance. These results showed that at least 7 mm thickness of the acetylated region with 15% WPG was required to suppress the fungal decay of acetylated wood under laboratory conditions.
  • Comparison of Dehydrogenation Polymers by Commercial Enzymes, Laccase from Rhus vernicifera and Horseradish Peroxidase
    Tatsuya Matsumoto, Keiichi Koda, Kengo Shigetomi, Manish Kumar, Yasumitsu Uraki
    Lignin 1 20 - 28 2020/01 [Refereed][Not invited]
  • Keiichi Koda, Shogo Taira, Atsushi Kubota, Tomofumi Isozaki, Xiangyu You, Yasumitsu Uraki, Kazuki Sugimura, Yoshiyuki Nishio
    Journal of Wood Chemistry and Technology 39 (3) 198 - 213 0277-3813 2019/05/04 [Refereed][Not invited]
  • Md. Momotaz Ali, Nutthira Pakkang, Shogo Taira, Keiichi Koda, Koki Itoyama, Yasumitsu Uraki
    Journal of Wood Chemistry and Technology 39 (4) 282 - 295 0277-3813 2019 [Refereed][Not invited]
  • Shogo Taira, Makoto Kurihara, Keiichi Koda, Kazuki Sugimura, Yoshiyuki Nishio, Yasumitsu Uraki
    Cellulose 26 (1) 569 - 580 0969-0239 2019/01 [Refereed][Invited]
  • Nutthira Pakkang, Yasumitsu Uraki, Keiichi Koda, Manit Nithitanakul, Ampira Charoensaeng
    Journal of Surfactant and Detergents 21 (6) 809 - 816 1097-3958 2018/08 [Refereed][Not invited]
  • Linping Wang, Yasumitsu Uraki, Keiichi Koda, Aori Gele, Xuesong Zhou, Fangeng Chen
    Holzforschung 73 (4) 363 - 369 0018-3830 2018 [Refereed][Not invited]
     
    Abstract The molar mass (MM) and polydispersity indices (PDI) of acetylated hardwood kraft lignin (Ac-HWKL) and Ac-HWKL fractions were measured by size-exclusion chromatography with multi-angle laser light scattering (SEC-MALLS). The detectors worked at LL658 nm and LL785 nm. The MM of Ac-HWKL measured at 785 nm was much smaller than that measured at 658 nm. The number-average (Mn) and weight-average (Mw) molar masses of Ac-HWKL determined at 785 nm were approximately 6.2 and 6.5 times larger, respectively, than the values estimated using a conventional calibration curve created with authentic polystyrene standards in tetrahydrofuran (THF). Based on the Mw of Ac-HWKL fractions, the Mark-Houwink-Sakurada equation for Ac-HWKL was established to be [η]/ml g−1=0.320 M0.24 in THF and [η]/ml g−1=0.142 M0.26 in dimethyl sulfoxide (DMSO). These results demonstrate that Ac-HWKL has a more compact structure in an organic solvent than polystyrene.
  • Toshizumi Miyamoto, Keiichi Koda, Arata Kawaguchi, Yasumitsu Uraki
    MICROBIAL ECOLOGY 74 (2) 322 - 331 0095-3628 2017/08 [Refereed][Not invited]
     
    Despite the importance of litter decomposition under snow cover in boreal forests and tundra, very little is known regarding the characteristics and functions of litter-decomposing fungi adapted to the cold climate. We investigated the decomposition of oak leaves in a heavy snowfall forest region of Japan. The rate of litter weight loss reached 26.5% during the snow cover period for 7 months and accounted for 64.6% of the annual loss (41.1%). Although no statistically significant lignin loss was detected, decolourization portions of oak leaf litter, which was attributable to the activities of ligninolytic fungi, were observed during snow cover period. This suggests that fungi involved in litter decomposition can produce extracellular enzymes to degrade lignin that remain active at 0 A degrees C. Fungi were isolated from oak leaves collected from the forest floor under the snow layer. One hundred and sixty-six strains were isolated and classified into 33 operational taxonomic units (OTUs) based on culture characteristics and nuclear rDNA internal transcribed spacer (ITS) region sequences. To test the ability to degrade lignin, the production of extracellular phenoloxidases by isolates was quantified at 0 A degrees C. Ten OTUs (9 Ascomycota and 1 Basidiomycota) of fungi exhibited mycelial growth and ligninolytic activity. These results suggested that some litter-decomposing fungi that had the potential to degrade lignin at 0 A degrees C significantly contribute to litter decomposition under snow cover.
  • Ningning Cheng, Keiichi Koda, Yutaka Tamai, Yoko Yamamoto, Taichi E. Takasuka, Yasumitsu Uraki
    BIORESOURCE TECHNOLOGY 232 126 - 132 0960-8524 2017/05 [Refereed][Not invited]
     
    Amphipathic lignin derivatives (A-LDs) prepared from the black liquor of soda pulping of Japanese cedar are strong accelerators for bioethanol production under a fed-batch simultaneous enzymatic saccharification and fermentation (SSF) process. To improve the bioethanol production concentration, conditions such as reaction temperature, stirring program, and A-LDs loadings were optimized in both small scale and large scale fed-batch SSF. The fed-batch SSF in the presence of 3.0 g/L A-LDs at 38 degrees C gave the maximum ethanol production and a high enzyme recovery rate. Furthermore, a jar-fermenter equipped with a powerful mechanical stirrer was designed for 1.5 L-scale fed-batch SSF to achieve rigorous mixing during high substrate loading. Finally, the 1.5 L fed-batch SSF with a substrate loading of 30% (w/v) produced a high ethanol concentration of 87.9 g/L in the presence of A-LDs under optimized conditions. (C) 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
  • Yoko Yamamoto, Ningning Cheng, Keiichi Koda, Kiyohiko Igarashi, Yutaka Tamai, Yasumitsu Uraki
    CELLULOSE 24 (4) 1849 - 1862 0969-0239 2017/04 [Refereed][Not invited]
     
    Amphipathic lignin derivatives (ALDs), prepared from hardwood acetic acid lignin and softwood soda lignin via coupling with a mono-epoxylated polyethylene glycol, have been reported to improve the enzymatic saccharification efficiency of lignocellulose while maintaining significant residual cellulase activity after saccharification. We previously demonstrated that the effect of ALDs was caused by a direct interaction between ALDs and Cel6A (or CBH II). In this study, a different ALD was prepared from softwood kraft lignin in addition to aforementioned ALDs. The interactions between all the ALDs and the enzymes other than Cel6A, such as Cel7A and Cel7B, in a cellulase cocktail were investigated using surface plasmon resonance. The kraft lignin-based ALD showed the highest residual cellulase activity among all ALDs and an improved cellulolytic enzyme efficiency similar to those of the other ALDs. All ALDs were found to directly associate with major enzymes in the cellulase cocktail, Cel6A and Cel7A (or CBH I), but not with Cel7B (or EG I). In addition, the ALDs showed a much higher affinity to amino groups than to hydroxy and carboxy groups. In contrast, polyethylene glycol (molecular mass 4000 Da), one part of the ALD and a previously reported enzymatic saccharification enhancer, did not adsorb onto any enzymes in the cellulase cocktail or the amino group. Size exclusion chromatography demonstrated that the ALDs formed self-aggregates in both water and chloroform; the formation process in the latter was especially unique. Therefore, we conclude that the high residual cellulase activity is attributed to the direct association of ALD aggregates with the CBH group.
  • Xiangyu You, Junlei Duan, Keiichi Koda, Tatsuhiko Yamada, Yasumitsu Uraki
    HOLZFORSCHUNG 70 (7) 661 - 671 0018-3830 2016/07 [Refereed][Not invited]
     
    Electrodes has been prepared for application in an electric double layer capacitor (EDLC) based on polyethylene glycol lignin (PEGL) and soda lignin (SL) derived from cedar wood. Fibers with a diameter of 23 mu m were prepared by direct melt electrospinning of PEGL. Much finer fibers of 3.6 mu m diameter were obtained by dry electrospinning of 70% PEGL in a dimethyl formamide (DMF) solution at 145 degrees C. The dry electrospinning of SL alone in an alkaline aqueous solution was not achievable, but this was possible of a mixture of SL and polyethylene glycol (M-w = 500 000) at a ratio of 99/1, which resulted in thin SL fibers with a diameter of 0.85 mu m. These fibers were converted into activated carbon fibers (ACFs) by thermostabilization, carbonization, and steam activation. The specific Brunauer, Emmett and Teller (BET) surface areas of the resulting PEGL-ACFs and SL-ACFs were 1880 m(2) g(-1) and 1411 m(2) g(-1), respectively. PEGL-ACFs electrodes with an organic electrolyte exhibited an impedance of 1.6 Omega and a specific capacitance of 92.6 F g(-1) at a scan rate of 1 A g(-1), and the SL-ACFs electrodes had an impedance and specific capacitance of 4.5 Omega and 55.6 F g(-1), respectively.
  • Xiangyu You, Keiichi Koda, Tatsuhiko Yamada, Yasumitsu Uraki
    JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY 36 (6) 418 - 431 0277-3813 2016 [Refereed][Not invited]
     
    Activated carbon fibers (ACFs) with large surface area were easily prepared from melt-spun fibers of polyethylene glycol lignin (PEGL). To fabricate electric double-layer capacitors (EDLCs) with a wide potential window and a high energy density in an EDLC package, electrodes (mainly composed of ACFs) were internally laminated and connected in series, in parallel, or in a series/parallel combination. Such resultant EDLCs are termed internal tandem (IT) EDLCs. As expected, the potential window was expanded by the series connection, and the capacitance was increased by the parallel connection. As a result, the energy density in the parallel-connected EDLC was remarkably increased by 66% (16.6 Wh kg(-1)) compared with that of a single-cell EDLC. The EDLC with the combination connection showed both advantages. Thus, based on the package weight, the electrochemical performance of the EDLCs was remarkably improved by the IT-type lamination of electrodes.
  • Xiangyu You, Keiichi Koda, Tatsuhiko Yamada, Yasumitsu Uraki
    HOLZFORSCHUNG 69 (9) 1097 - 1106 0018-3830 2015/11 [Refereed][Not invited]
     
    Lignin-based activated carbon fibers (ACFs) were prepared by electrospinning of hardwood acetic acid lignin (HW-AAL) solution followed by thermostabilization, carbonization, and steam activation. The thermostabilization process was able to be remarkably shortened from 38 h to 3 h with hexamethylenetetramine (hexamine) in binary solvents, AcOH/CCl4 (8/2), when compared with conventional thermostabilization processes. The resultant ACFs possessed higher specific surface area (2185 m(2) g(-1)) than those from commercial activated carbon and electrospun lignin fibers without hexamine. These ACFs also exhibited good electrical capacitance (133.3 F g(-1) at a current density of 1 A g(-1)) as electrodes of electric double layer capacitor (EDLC) are efficient not only due to their large surfaces area but also due to their porous structure with well-developed micropores (diameter: 0.5-1.3 nm). High energy density and power density of this EDLC (42 Wh kg(-1) and 91 kW kg(-1), respectively) were also achieved.
  • Qiang Li, Keiichi Koda, Arata Yoshinaga, Keiji Takabe, Masatsugu Shimomura, Yuji Hirai, Yutaka Tamai, Yasumitsu Uraki
    JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 63 (18) 4613 - 4620 0021-8561 2015/05 [Refereed][Not invited]
     
    To elucidate the influence of wood polysaccharide components on lignin formation in vitro, models for polysaccharide matrix in wood secondary cell wall were fabricated from two types of bacterial cellulosic films, flat film (FBC) and honeycomb-patterned film (HPBC), as basic frameworks by depositing xylan onto the films. An endwise type of dehydrogenative polymerization, Zutropfverfahren, of coniferyl alcohol was attempted in the films with/without xylan. The resultant dehydrogenation polymer (DHP) was generated inside and outside xylan-deposited films, whereas DHP was deposited only outside the films without xylan. The amount of the generated DHP in the xylan-deposited films was larger than that in the films without xylan. The frequency of 8-O-4' interunitary linkage in DHP was also increased by the xylan deposition. These results suggest that xylan acts as a scaffold for DHP deposition in polysaccharides matrix and as a structure regulator for the formation of the 8-O-4' linkage. In addition, mechanical properties, i.e., tensile strength and modulus of elasticity (MOE), of both cellulosic films were found to be augmented by the deposition of xylan and DHP. Especially, DHP deposition remarkably enhanced MOE. Such effects of xylan on DHP formation and augmentation of mechanical strength were clearly observed for HPBC, revealing that HPBC is a promising framework model to investigate wood cell wall formation in vitro.
  • Yoko Yamamoto, Ningning Cheng, Kiyohiko Igarashi, Keiichi Koda, Yasumitsu Uraki
    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY 249 0065-7727 2015/03 [Refereed][Not invited]
  • Ningning Cheng, Yoko Yamamoto, Keiichi Koda, Yutaka Tamai, Yasumitsu Uraki
    BIORESOURCE TECHNOLOGY 173 104 - 109 0960-8524 2014/12 [Refereed][Not invited]
     
    Amphipathic lignin derivatives (A-LDs) were already demonstrated to improve enzymatic saccharification of lignocellulose. Based on this knowledge, two kinds of A-LDs prepared from black liquor of soda pulping of Japanese cedar were applied to a fed-batch simultaneous saccharification and fermentation (SSF) process for unbleached soda pulp of Japanese cedar to produce bioethanol. Both lignin derivatives slightly accelerated yeast fermentation of glucose but not inhibited it. In addition, ethanol yields based on the theoretical maximum ethanol production in the fed-batch SSF process was increased from 49% without A-LDs to 64% in the presence of A-LDs. (C) 2014 Elsevier Ltd. All rights reserved.
  • Ina Winarni, Keiichi Koda, Totok K. Waluyo, Gustan Pari, Yasumitsu Uraki
    JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY 34 (3) 157 - 168 0277-3813 2014/07 [Refereed][Not invited]
     
    The aim of this research is to develop an enzymatic saccharification process of sago starch waste, with a small charge of cellulase. The waste contained a significant amount of residual starch, which was recovered as glucose by mild acid hydrolysis. The starch-free residue was subjected to soda-anthraquinone pulping to yield soda pulp and soda lignin. The lignin was converted to amphipathic lignin derivatives by the reaction with epoxylated polyethylene glycol analogues. The pulp was hydrolyzed with cellulase (Genencor GC220), with the amphipathic derivatives, to yield glucose. The lignin derivative-assisted, enzymatic saccharification was repeatedly conducted by reusing cellulase recovered by ultrafiltration from saccharification media. Saccharification efficiency with the derivatives was maintained at a high level even after the fourth run of saccharification, while the efficiency was remarkably decreased by repeated use of cellulase without additive. Thus, the amphipathic sago lignin derivatives enabled repeated use of cellulase for saccharification of sago starch waste.
  • Jian Lin, Keiichi Koda, Satoshi Kubo, Tatsuhiko Yamada, Makiko Enoki, Yasumitsu Uraki
    JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY 34 (2) 111 - 121 0277-3813 2014/06 [Refereed][Not invited]
     
    PEG-lignin fibers obtained by a solvolysis pulping of Japanese cedar with polyethylene glycol (PEG) 400 were successfully converted into defective-free, infusible fibers as a precursor for carbon fibers (CFs) by chemical curing followed by oxidative thermostabilization. The curing was performed by immersing PEG-lignin fibers in an aqueous mixed solution of hexamethylenetetramine (60g/L) and hydrochloric acid (3M) at 85 degrees C for 1h, resulting in the formation of crosslinkages between lignin molecules through methylene groups. These cured fibers were completely thermostabilized upon heating up to 250 degrees C at a heating rate of 2 degrees C/min under an air atmosphere. Finally, the thermostabilized fibers were carbonized to yield CFs, which showed about 1.5times the tensile strength of our CFs previously prepared.
  • Tomohiro Aso, Keiichi Koda, Satoshi Kubo, Tatsuhiko Yamada, Isamu Nakajima, Yasumitsu Uraki
    JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY 33 (4) 286 - 298 0277-3813 2013/12 [Refereed][Not invited]
     
    Lignin-based amphiphiles were prepared from the waste liquors of softwood and hardwood kraft pulpings (SKLliq and HKLliq, respectively) and their isolated lignins (SKL and HKL, respectively) by a reaction with several epoxylated polyethylene glycol analogues: polyethylene glycol diglycidylether (PEGDE), its monoglycidyl ether (EPEG), and dodecyloxypolyethylene glycol glycidyl ether (DAEO). The effect of these amphiphiles on cement dispersity was examined at 6 degrees C and 20 degrees C. Generally, only half the amount of EPEG- and PEGDE-series (e.g., 0.4%) was required to achieve the same cement dispersibility (e.g., p value of 2) compared to lignosulfonate (LS) (e.g., 0.8%). DAEO-lignin derivatives with the highest surface activity did not show cement dispersibility, suggesting no correlation between cement dispersibility and surface activity of the amphiphiles. Thus, together with the test of bending strength, it was found that the amphiphiles prepared from isolated lignins and EPEG were promising cement dispersants, which were available even in the wintertime without losing mechanical strength.
  • Ina Winarni, Chihiro Oikawa, Tatsuhiko Yamada, Kiyohiko Igarashi, Keiichi Koda, Yasumitsu Uraki
    BIORESOURCES 8 (2) 2195 - 2208 1930-2126 2013 [Refereed][Not invited]
     
    Synthesized amphipathic lignin derivatives comprised of acidic acid lignin (AL) with poly(ethylene glycol) diglycidyl ether (PEGDE), ethoxy-(2-hydroxy)-propoxy-poly(ethylene glycol) glycidyl ether (EPEG) or dodecyloxy-poly(ethylene glycol) glycidyl ether (DAEO) were added before the enzymatic saccharification of unbleached cedar pulp along with two commercially available cellulases, Meicelase and Genencor GC220. At the same filter paper unit (FPU) dosage, GC220 showed higher sugar yield than Meicelase. The difference was attributed to the composition of processive and non-processive endoglucanase activities per FPU; GC220 had higher such activities than Meicelase. The sugar yield was significantly improved by the addition of the lignin derivatives. In addition, residual activities after the saccharification were maintained at the higher level by their addition than with polyethylene glycol (PEG) 4000. In particular, EPEG-AL yielded the complete recovery of cellulase activity when using 20 FPU/g of substrate. It was found that the lignin derivatives were directly associated with Cel6A, one of cellulase components, whereas PEG 4000 was not. Thus, it is evident that the lignin derivatives are promising agents to improve the enzymatic saccharification of cellulase.
  • Yasumitsu Uraki, Yusuke Sugiyama, Keiichi Koda, Satoshi Kubo, Takao Kishimoto, John F. Kadla
    BIOMACROMOLECULES 13 (3) 867 - 872 1525-7797 2012/03 [Refereed][Not invited]
     
    Several lignin model polymers and their derivatives comprised exclusively of beta-O-4 or 8-O-4' interunitary linkages were synthesized to better understand the relation between the thermal mobility of lignin, in particular, thermal fusibility and its chemical structure; an area of critical importance with respect to the biorefining of woody biomass and the future forest products industry. The phenylethane (C6-C2)-type lignin model (polymer 1) exhibited thermal fusibility, transforming into the rubbery/liquid phase upon exposure to increasing temperature, whereas the phenylpropane (C6-C3)-type model (polymer 2) did not, forming a char at higher temperature. However, modifying the C gamma or 9-carbon in polymer 2 to the corresponding ethyl ester or acetate derivative imparted thermal fusibility into this previously infusible polymer. FT-IR analyses confirmed differences in hydrogen bonding between the two model lignins. Both polymers had weak intramolecular hydrogen bonds, but polymer 2 exhibited stronger intermolecular hydrogen bonding involving the C gamma-hydroxyl group. This intermolecular interaction is responsible for suppressing the thermal mobility of the C6-C3-type model, resulting in the observed infusibility and charring at high temperatures. In fact, the C gamma-hydroxyl group and the corresponding intermolecular hydrogen bonding interactions likely play a dominant role in the infusibility of most native lignins.
  • Jian Lin, Satoshi Kubo, Tatsuhiko Yamada, Keiichi Koda, Yasumitsu Uraki
    BIORESOURCES 7 (4) 5634 - 5646 1930-2126 2012 [Refereed][Not invited]
     
    A thermally fusible softwood lignin was directly isolated by a solvolysis of cedar wood chips with a mixture of polyethylene glycol 400 (PEG 400) and sulfuric acid. Its fusibility was found to be due to a PEG moiety introduced into the lignin by the solvolysis. The lignin was easily formed into fibers by melt-spinning at temperatures ranging from 145 to 172 degrees C without any modification. The lignin fibers could be converted into infusible fibers as a precursor for carbon fibers (CFs) by conventional oxidative thermal stabilization processing in air or a stream of oxygen for 2 days. We found that the infusible fibers resulted from the partial cleavage of the PEG moiety from the lignin fibers after treatment with 6 M hydrochloric acid at 100 degrees C for 2 h. The infusible fibers were converted into CFs with a tensile strength of 450 MPa by carbonization at 1000 degrees C under a N-2 stream.
  • Yasumitsu Uraki, Keiichi Koda, Tatsuhiko Yamada, Chihiro Oikawa, Tomohiro Aso
    FUNCTIONAL MATERIALS FROM RENEWABLE SOURCES 1107 243 - + 0097-6156 2012 [Refereed][Not invited]
     
    Technical lignins including water-insoluble isolated lignins were easily converted to water-soluble derivatives by the reaction with several types of epoxidized polyethylene glycol derivatives. The resulting lignin-based derivatives were soluble in water and organic solvents, thus having amphiphilic property. We found novel functions of the amphiphiles, such as the uses as cellulase-aid agent and cement dispersant in addition to the surfactant action. This article reviews the functions in relation to the development of biorefining processes for Japanese woody biomass.
  • Tomohiro Aso, Keiichi Koda, Satoshi Kubo, Tatsuhiko Yamada, Isamu Nakajima, Yasumitsu Uraki
    PROCEEDING OF THE 4TH INTERNATIONAL CONFERENCE ON PULPING, PAPERMAKING AND BIOTECHNOLOGY (ICPPB '12), VOLS. I AND II 90 - 93 2012 [Refereed][Not invited]
     
    Novel, non-ionic type cement dispersants were prepared from various isolated lignins, softwood and hardwood haft lignins, black liquors from softwood and hardwood haft pulpings, and softwood soda lignin by the reaction with several epoxylated polyethylene glycol (PEG) derivatives, polyethylene glycol diglycidylether (PEGDE), its monoglycidyl ether (EPEG) and dodecyloxypolyethylene glycol glycidyl ether (DAEO). Cement dispersibility of the resultant lignin-based derivatives were examined at 6 C and 20 degrees C. EPEG- and PEGDE-based lignin derivatives gave higher dispersity of cement than lignosulfonate (LS) at both temperatures. Among all the lignin derivatives, EPEG-softwood haft lignin showed the highest cement dispersibility. On the other hand, DAEO-based derivatives did not exhibit cement dispersibility in spite of the fact that it showed the highest surface activity. Thus, it was found that there was no correlation between cement dispersibility and surface activity of lignin-based amphiphiles.
  • Jian Lin, Satoshi Kubo, Tatsuhiko Yamada, Keiichi Koda, Yasumitsu Uraki
    PROCEEDING OF THE 4TH INTERNATIONAL CONFERENCE ON PULPING, PAPERMAKING AND BIOTECHNOLOGY (ICPPB '12), VOLS. I AND II 860 - 863 2012 [Refereed][Not invited]
     
    Solvolysis of cedar Wood with a mixture of polyethylene glycol 400 (PEG 400) and sulfuric acid gave thermally fusible softwood lignin (PEG-lignin), which was easily spun into fibers by melt-spinning at a temperature range of 145 to 172 degrees C without any modification. It took more than 2 days to convert the fibers into thermostabilized ones by the oxidation under air or oxygen atmosphere; that is termed as "conventional thermostabilization". As a shortening process, we developed "chemical thermostabilization"; the PEG-lignin fibers were converted into infusible fibers as a precursor for carbon fibers (CFs) by immersing at 100 degrees C for 2 h. CFs with a tensile strength of 450 MPa were obtained by carbonization at 1000 degrees C under a N-2 stream. The resultant CFs were, in turn, readily converted to activated CFs with large specific surface area of 3060 m(2)/g by the steam activation. This effective activation was attributed to defects generated by chemical thermostabilization, from which the activation proceeded into inside of fibers.
  • Yasumitsu Uraki, Yutaka Tamai, Takuro Hirai, Keiichi Koda, Hiroshi Yabu, Masatsugu Shimomura
    MATERIALS SCIENCE & ENGINEERING C-MATERIALS FOR BIOLOGICAL APPLICATIONS 31 (6) 1201 - 1208 0928-4931 2011/08 [Refereed][Not invited]
     
    Wood cell wall, composed of polysaccharides (cellulose and hemicelluloses) and an aromatic polymer (lignin), exhibits a honeycomb-like alignment. We have been making attempts to fabricate cellulose-based materials to reconstruct these wood components artificially, mimicking their formation processes. Those attempts are aiming not only at better understanding of the significance and the function of each wood component, but also at providing a novel, biomass-based polymer material with functionality. This article outlines a protocol to prepare honeycomb-patterned cellulose films with two different polymorphisms, carrying different pore sizes, as a basic framework of the artificial cell wall structure. It also illustrates the effect of the presence of hemicellulose and lignin on the physical property of the honeycomb-patterned cellulose films, when they were adsorbed onto the films. (C) 2010 Elsevier B.V. All rights reserved.
  • Keiichi Koda, Satoshi Kubo, Yasumitsu Uraki
    ACS Symposium Series 1067 261 - 277 1947-5918 2011 [Refereed][Not invited]
     
    Development of low-cost, value-added bio-materials from technical lignins is essential in terms of complete utilization of woody biomass components (biorefining). A simply designed chemical modification may provide technical lignins with some unique properties: thermal fusibility, thermal moldability, amphiphilicity, and miscibility with synthetic polymers. Here, the fundamental characteristics of technical lignins are first overviewed. Second, recent progress in chemical modification of technical lignins for industrial application is reviewed. Finally, newly developed lignin-containing materials with functionality are discussed. © 2011 American Chemical Society.
  • Yasumitsu Uraki, Harumi Homma, Chihiro Oikawa, Tomohiro Aso, Keiichi Koda
    16TH INTERNATIONAL SYMPOSIUM ON WOOD, FIBER AND PULPING CHEMISTRY, PROCEEDINGS, VOLS I & II 165 - 169 2011 [Refereed][Not invited]
     
    We have developed a conversion method of isolated lignins to amphiphiles with three polyethylene glycol (PEG) analogues bearing epoxy groups, termed as PEGDE, EPEG and DAEO. These lignin-based amphiphiles showed significant surface activity. DAEO-derivative revealed the highest activity as comparable to Triton X-100, commercially available nonionic surfactant. We found another useful application of these lignin-based amphiphiles in addition to its utilization as a surfactant. When the amphipiles were added to pulp suspension in a buffered solution together with cellulase, the enzymatic saccharification yields were significantly improved and residual cellulase activity after the saccharification was maintained at higher levels than that without the amphiphiles. EPEG-derivative indicated the highest residual activity. These results suggest that the lignin-based amphiphiles can be used as a cellulase-aid agent, leading to reduction of saccharification cost. EPEG and DAEO-derivatives are also found to act as a cement admixture, which was known to reduce the amount of water used for well dispersing cement, and was very often produced from lignosulfates. These derivatives showed a superior dispersibility for cement to lignosulfates in spite of the fact that it is a nonionic surfactant. In addition, such the derivatives could be prepared directly from black liquor of kraft pulping by one step reaction without isolation of kraft lignin from the black liquor. Thus, a new type cement dispersant or admixture, as well as cellulase-aid agent, was readily prepared from isolated lignins, such as kraft lignin and organosolv lignins, by our developed modification method-with PEG analogues.
  • Teuku Beuna Bardant, Chihiro Oikawa, Masanobu Nojiri, Keiichi Koda, Yanni Sudiyani, Tatsuhiko Yamada, Yasumitsu Uraki
    MOKUZAI GAKKAISHI 56 (6) 420 - 426 0021-4795 2010 [Refereed][Not invited]
     
    A huge amount of lignocellulosic wastes are disposed on an industrial scale as unused biomass both in Japan and in Southeast Asia : including forest thinnings of Japanese cedar wood and empty fruit bunches (EFB) of the oil palm tree. Supposing the production of platform compounds from such unused biomass through enzymatic saccharification, we have developed a cellulase-aid agent by the conversion of acetic acid lignin into an amphiphilic derivative (PE-AL). EFB pulps with 1096 and 12% residual lignin and cedar pulp with 11% residual lignin were prepared by kraft and soda pulping processes, respectively, as a pretreatment of enzymatic saccharification. An addition of PE-AL significantly improved the saccharification yield of the cedar pulp, while it improved those of EFB pulps dramatically. After the enzymatic saccharification, the cellulase activity remained in the presence of PEAL, although no activity was detected in the absence of PE-AL.
  • Harumi Homma, Satoshi Kubo, Tatsuhiko Yamada, Keiichi Koda, Yasuyuki Matsushita, Yasumitsu Uraki
    JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY 30 (2) 164 - 174 0277-3813 2010 [Refereed][Not invited]
     
    To make use of technical lignins as a nonionic polymeric surfactant, we have already reported the modification of acetic acid lignin (AL) to amphiphilic derivatives by polyoxyethylation using two types of polyethylene glycol (PEG) with diglycidyl (PEGDE) and monoglycidyl (EPEG) groups.[1] Kraft lignin (KL) was converted to amphiphiles in a similar manner. The resultant KL derivatives also indicated high surface activity. Polyethylene glycol with long alkyl chain was introduced to AL, KL, and lignosulfonate (LS) to prepare surfactants of high performance, using dodecyloxy-polyethylene glycol glycidyl ether (DAEO). The resultant DAEO-derivatives showed lower critical micelle concentration by 2-4 orders of magnitude than the corresponding PEGDE- and EPEG-derivatives. The DAEO-derivatives from LS showed better dispersibility for gypsum paste, one of cement components, than LS.
  • Wood density variations of tropical wood species: Implications to the physical and chemical properties of sawdust
    Rizki Maharani, Yutaka Tamai, Keiichi Koda, Yasuo Kojima, Minoru Terazawa
    Wood Research Journal (Journal of Indonesian Wood Research Society) 1 (1) 34 - 39 2010 [Not refereed][Not invited]
  • Yasumitsu Uraki, Keiichi Koda, Takao Kishimoto, Satoshi Kubo
    RESEARCH PROGRESS IN PAPER INDUSTRY AND BIOREFINERY (4TH ISETPP), VOLS 1-3 315 - 318 2010 [Refereed][Not invited]
     
    We have first found that hardwood acetic acid lignin (HAL), one of organosolv lignins, had fusibility, which had never reported for other isolated lignins. HAL can be transformed into fibers by melt spinning, and then carbon fibers and activated carbon fibers by heat treatments. Kubo and his colleagues successfully prepared fibers by melt spinning from a hardwood organosolv lignin and a hardwood kraft lignin. The moldability of these lignins was attributed to fusibility of isolated lignins. However, the relationship between the presence of beta-O-4 bond, the major interunitary linkage of lignin, and its fusibility was not elucidated. We investigated the relationship, using artificially synthesized lignin polymers consisting exclusively of beta-O-4 bond having phenylpropane guaiacyl moiety. As a result, the model polymer was not transformed into a molten state, although it showed a glass transition. It was found, from FT-IR measurement with variable temperature mode, that its molecular motion was suppressed by the formation of intermolecular hydrogen bonding of a primary hydroxyl group at gamma-position. Therefore, the fusibility of organosolv lignins was attributed to the modification of primary hydroxyl group with the cooking solvents used for the pulping processes.
  • Yuka Tasaki, Yasumitsu Uraki, Keiichi Koda, Sadaaki Yamamoto, Hiroshi Yabu, Masatsugu Shimomura
    RESEARCH PROGRESS IN PAPER INDUSTRY AND BIOREFINERY (4TH ISETPP), VOLS 1-3 1465 - 1468 2010 [Refereed][Not invited]
     
    Honeycomb-patterned cellulose films were prepared, and coated with arabinogalactan, a larch hemicellulose. An application of the hemicellulose-coated, honeycomb-patterned cellulose films was proposed. First, we attempted to control the pore sizes of honeycomb-patterned bacterial cellulose (HPBC) films. HPBC films with pore sizes of 10, 15, and 20 mu m were successfully fabricated, but the one with a pore size of 5 mu m was not. Second, we evaluated the applicability of the arabinogalactan-coated, honeycomb-patterned regenerated cellulose (HPRC) films to scaffolds for hepatocyte culture. It was observed that the arabinogalactan-coated HPRC films had a unique adhesion of hepatocyte: formation of spheroid-like structure and insertion of individual globular cells each in the honeycomb pores.
  • Chihiro Oikawa, Keiichi Koda, Yasumitsu Uraki, Masanobu Nojiri, Tatsuhiko Yamada, Kiyohiko Igarashi
    RESEARCH PROGRESS IN PAPER INDUSTRY AND BIOREFINERY (4TH ISETPP), VOLS 1-3 1306 - 1309 2010 [Refereed][Not invited]
     
    An effective cellulase-aid agent has to be developed to establish an efficient saccharification system for bioethanol production from huge piles of unused, lignocellulosic biomass. We have successfully developed some types of lignin derivatives that enhance the efficiency of enzymatic hydrolysis of unbleached pulp with cellulase and help to maintain its original activity after repeated use. These cellulase-aid agents were prepared by the conversion of acetic acid lignin into amphiphilic derivatives with polyethylene glycol-related compounds.
  • Yoshie Kanazawa, Takao Kishimoto, Keiichi Koda, Kazuhiko Fukushima, Yasumitsu Uraki
    JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY 29 (2) 178 - 190 0277-3813 2009 [Refereed][Not invited]
     
    Dimeric lignin model compounds with non-phenolic and phenolic moieties and a -O-4 type artificial lignin polymer were subjected to thioacidolysis to evaluate the reaction efficiency of thioacidolysis for cleavage of -O-4 interunitary linkage. The obtained yields of thioethylated monomeric products from the dimeric lignin model compounds reached nearly 100% under the conventional condition, whereas that from the artificial lignin polymer was as low as 74%. Neither prolonged reaction time nor increased concentration of ethanethiol (the thioacidolysis reagent) enhanced the resulting monomer yields from the polymer (69-79%). Thioacidolysis of the lignin model compounds followed by HPSEC analysis also showed the dimeric model compounds were degraded almost quantitatively, but that the artificial lignin polymer was not. Thioacidolysis followed by desulfurization gave at least one dimeric product resulting from incomplete -O-4 cleavage at significant yield. These results suggested the conventional thioacidolysis could not achieve quantitative cleavage of -O-4 linkages in lignin macromolecules.
  • Yoshie Kanazawa, Takao Kishimoto, Keiichi Koda, Kazuhiko Fukushima, Yasumitsu Uraki
    PROCEEDINGS OF INTERNATIONAL CONFERENCE ON PULPING, PAPERMAKING AND BIOTECHNOLOGY 2008: ICPPB '08, VOL I 659 - 663 2008 [Refereed][Not invited]
     
    Non-phenolic and phenolic lignin-dimeric model compounds and a beta-O-4 type artificial lignin polymer have been subjected to thioacidolysis with ethanethiol and boron tribromide etherate to evaluate the reaction efficiency of thioacidolysis for cleavage of beta-O-4 linkage. The obtained yields of thioacidolysis products from dimeric model compounds reached nearly 100% under conventional thioacidolysis conditions, whereas those for the artificial lignin polymer were only at around 70%. Neither prolonged reaction time nor increasing In the concentration of the thioacidolysis reagent enhanced the yields of thioacidolysis products. Thioacidolysis of the lignin models followed by high performance size exclusion chromatographic (HPSEC) analysis also showed that dimeric model compound was degraded almost quantitatively, but artificial lignin polymer was not. These results suggested that conventional thioacidolysis could not achieve quantitative cleavage beta-O-4 linkages in lignin macromolecules.
  • The change of lignin structure of the triploid Polulus tomentosa during kraft pulping
    Liu Yu, Zhan Huai-yu, Chen Jia-chuan, Keiichi Koda, Dimitris Argyropoulos
    Zhongguo Zaozhi Xuebao (Transaction of China Pulp and Paper) 21 (4) 14 - 18 2006 [Refereed][Not invited]
  • H Goto, K Koda, GL Tong, Y Matsumoto, G Meshitsuka
    JOURNAL OF WOOD CHEMISTRY AND TECHNOLOGY 26 (1) 81 - 93 0277-3813 2006 [Refereed][Not invited]
     
    To evaluate the effect of the presence of carbohydrates on the determination of the methoxyl content of lignin, the mechanism of acid-catalyzed reaction of lignin methoxyl groups with iodide ion to form methyl iodide was evaluated using carbohydrate and lignin model compounds. Not only the iodide concentration but also the acid concentration was found to significantly affect the rate of formation of methyl iodide. This fact and Hammett plots of the relative reaction rates observed for several model compounds suggest an S(N)2cA reaction mechanism for methyl iodide formation. Carbohydrates interfered with the rate of formation of methyl iodide, probably by acting as Lewis bases. Interestingly, the study also revealed that a certain amount of methyl iodide could arise from carbohydrates even when the carbohydrates did not contain methoxyl groups as potential precursors to methyl iodide. These sources of error were significant when methoxyl content was determined for samples with low lignin content.
  • H Goto, K Koda, GL Tong, Y Matsumoto, G Meshitsuka
    JOURNAL OF WOOD SCIENCE 51 (3) 312 - 314 1435-0211 2005 [Refereed][Not invited]
  • K Koda, AR Gaspar, L Yu, DS Argyropoulos
    HOLZFORSCHUNG 59 (6) 612 - 619 0018-3830 2005 [Refereed][Not invited]
     
    An integrated picture of the distribution of functional groups should be provided as a function of molecular size within residual kraft lignins. With this goal we developed a reliable and reproducible method for determination of the molecular weight and molecular weight distribution of residual kraft lignins (RKLs) over the whole delignification range. In general, our data indicate that for reliable measurement of the molecular weight and its distribution of residual lignin in pulps, the lignin-carbohydrate bonds have to be cleaved prior to size exclusion chromatography. The recently developed method for isolating residual lignins, which involves cellulolytic treatment followed by a mild acid hydrolysis step, was found to be the most suitable approach to achieve this. The molecular weight and polydispersity of all RKLs decreased as a function of delignification. As anticipated, the observed decrease in molecular weight was clearly reflected in the concomitantly decreasing amount of beta-O-4 structural linkages present. Similarly, the total phenolic hydroxyl content increased as the molecular weight of the RKLs decreased during kraft pulping. Despite the smaller size of the lignin remaining on the kraft fiber at the end of delignification, the preponderance of condensed phenolic structures within these lignins offers an explanation for delignification problems during bleaching.
  • DS Argyropoulos, YH Hou, R Ganesaratnam, DN Harpp, K Koda
    HOLZFORSCHUNG 59 (2) 124 - 131 0018-3830 2005 [Refereed][Not invited]
     
    A novel analytical protocol for the absolute determination of the various polysulfide species present in alkaline aqueous media was developed. The method is comprised of alkylating polysulfide ions with dimethyl sulfate, followed by quantitative proton NMR spectroscopy using 1,3,5-tributyl benzene as the internal standard. In order to arrive at a quantitative acquisition protocol, a number of variables were examined in detail for their effect on the alkylation reaction, including the presence of oxygen, the amount of dimethyl sulfate and sodium hydroxide, and the various modes of adding the alkylating reagent to the reaction mixture. Most of these variables were found to play a role in determining the quantitative reliability of the procedure. Consequently, a method is described that can be used for the efficient and reliable quantitative detection of polysulfide ions. The protocol developed could be particularly useful in promoting our understanding of the intricate and delicate chemistry of polysulfide equilibria in aqueous alkaline media.
  • H Goto, K Koda, GL Tong, Y Matsumoto, G Meshitsuka
    2nd International Symposium on Technologies Of Pulping, Papermaking and Biotechnology on Fiber Plants, Proceedings 75 - 79 2004 [Refereed][Not invited]
     
    In an effort to evaluate the effect of the presence of carbohydrates on the determination of methoxyl content in lignin, an improved method similar to Baker's one was developed. The method employs a closed system for the HI treatment of sample with subsequent G C determination of the product (methyl iodide). Not only the iodide concentration but also the acid concentration wag found to significantly affect the formation rate of methyl iodide. This, and Hammett Plots of the relative reaction rate observed for several model compounds suggest an SN2cA reaction mechanism for methyl iodide formation. As predicted by this mechanism, carbohydrates interfered with the formation rate of methyl iodide, probably acting as Lewis base that consumes protons. Interestingly, our research also revealed that a certain amount of methyl iodide could arise from carbohydrates even when the carbohydrate did not contain a methoxyl group as a precursor of methyl iodide.$ These sources of error were significant when methoxyl content was determined for a sample with low lignin content.
  • K Koda, H Goto, H Shintani, Y Matsumoto, G Meshitsuka
    JOURNAL OF WOOD SCIENCE 47 (5) 362 - 367 1435-0211 2001 [Refereed][Not invited]
     
    Methanol liberation and methoxyl loss during chlorine bleaching of softwood kraft pulp were quantitatively investigated to estimate the degree of structural modification of lignin aromatics. An increase in the chlorine multiple led to enhanced methoxyl loss from lignin;. Our result, using pH-adjusted chlorine water (pH 5.7), by which chlorination under oxidation-favorable conditions was achieved, strongly supported the importance of the oxidation reaction by chlorine during delignification and lignin degradation. It was also suggested that methanol can be produced not only via catalytic hydrolysis by chlorine but via oxidative cleavage of the ether bond as well. The infrared spectrum of chlorolignins suggested that chlorine oxidation can open aromatic rings to muconic acid derivatives without cleaving ether bonding of the methoxyl group. No straight relation: between the methoxyl content and the kappa number of chlorinated pulps was shown, The methoxyl content of bleached kraft pulps subjected to successive chlorination and alkali extraction showed a good relation with the kappa number. This means that almost all the portions of the oxidatively modified lignin structure were successfully removed during these treatments, and the aromatic structures of residual lignin in chlorinated and alkali-extracted pulps were thought to remain intact.
  • Seung-Young Park, Keiichi Koda, Yuji Matsumoto, Gyosuke Meshitsuka, Kenji Iiyama
    Kamipa Gikyoushi (Japan TAPPI Journal) JAPAN TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUSTRY 54 (9) 1245 - 1251 0022-815X 2000 [Refereed][Not invited]
     
    As we attempt to preserve forests and to decrease impact on environment, the development of novel technologies for the utilization of rice straw, especially to achieve complete delignification with minimum silica removal during its pulping, seems to be important and significant. It was examined whether or not oxygen-weak base pulping is useful for rice straw to control silica removal in this study. Delignification, silica removal and carbohydrate retention of rice straw during oxygen-sodium sulfite pulping and oxygen-ammonia pulping were compared with those during conventional alkaline pulping and oxygen-sodium hydroxide pulping. By an oxygen-sodium sulfite pulping of rice straw, sufficient delignification could be achieved without significant removal of silica into cooking liquor. The carbohydrate yield of oxygen-sodium sulfite pulping method was quite high (more than 80%) even when 95% of delignification was achieved, which is supported by the high retention of both cellulose and hemicellulose. In contrast to this, carbohydrate yield of oxygen-ammonia pulping was found to be rather low, even though high retention of silica was achieved. Low carbohydrate yield by this pulping was attributed to the significant degradation of both cellulose and hemicellulose.
  • K Koda, H Shintani, Y Matsumoto, G Meshitsuka
    JOURNAL OF WOOD SCIENCE 46 (4) 339 - 341 1435-0211 2000 [Refereed][Not invited]
  • Seung-Young Park, Keiichi Koda, Yuji Matsumoto, Gyosuke Meshitsuka, Kenji Iiyama
    Japan TAPPI Journal JAPAN TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUSTRY 53 (11) 1492 - 1499 0022-815X 1999 [Refereed][Not invited]
     
    A systematic study on kinetics of delignification and silica removal is necessary for optimization and a control of rice straw pulping process. Delignification and silica removal from four fractions (internode, sheath, blade and ear) of rice straw were kinetically investigated under soda pulping conditions in the temperature ranges from 30 to 70°C and from 100 to 140°C. Both delignification and silica removal by sodium hydroxide treatment were suggested to be a pseudo first order reaction. The delignification progress of rice straw was separated clearly into at least two phases. About 80% delignification was achieved in the first phase even under a mild condition at 80°C under which the degradation reaction of wood lignin was almost impossible to occur. The delignification rates of the internode, sheath and blade are larger than that of ear. It was confirmed that silica removal is a kinetically easier process than delignification under alkali pulping conditions. The rate of silica removal is greater than that of delignification, and the former is easier to increase with increasing temperature. Therefore, it was concluded that complete delignification from rice straw without serious silica removal can not be achieved as long as sodium hydroxide is employed as a cooking reagent. Other components of cell wall (i.e. hemicellulose) had virtually no effect on the kinetic parameters of silica removal.
  • K Koda, H Shintani, Y Matsumoto, G Meshitsuka
    JOURNAL OF WOOD SCIENCE 45 (2) 149 - 153 1435-0211 1999 [Refereed][Not invited]
     
    A modified method was developed to evaluate how much chlorine is consumed by the oxidation reaction during the chlorine bleaching process. This evaluation is, in principle, based on the sum of chloride produced during the chlorination stage (C-stage) and produced during alkali treatment of both the C-stage effluent and the chlorinated pulp. Results obtained by this method proved that about 50%-75% of chlorine was consumed by the oxidation reaction during chlorine bleaching, depending on the reaction condition of chlorination. Even under a reaction condition that is not favorable to an oxidation reaction (low pH), approximately three electrons were abstracted from one lignin structural unit by chlorine bleaching. This result provides additional evidence for our recent observation that lignin is extensively oxidized during chlorine bleaching even when pure chlorine without any chlorine dioxide substitution was used.
  • H Shintani, K Koda, Y Matsumoto, G Meshitsuka
    ISWPC - 9TH INTERNATIONAL SYMPOSIUM ON WOOD AND PULPING CHEMISTRY - POSTER PRESENTATIONS 1041 - 1044 1997 [Refereed][Not invited]
     
    Unbleached hardwood kraft pulp and unbleached softwood kraft pulp were chlorinated at various levels of chlorine ratio (0.10-0.23), and were separated to chlorinated pulps and C-stage effluents. The amount of total organic carbon (TOC) and total organic chlorine (TOCl) of C-stage effluents increased with chlorine ratio for both hardwood and softwood kraft pulps. The TOCl/TOC ratios of C-stage effluents were almost constant (0.12) at any chlorine ratio for both hardwood and softwood kraft pulps. The chlorine content of the residual lignin in chlorinated pulp increased with chlorine ratio, and the organic chlorine per carbon of the residual lignin which was estimated roughly by E-stage effluent lignin were quite larger than 0.12 for both pulps (high chlorine ratio). These results indicate that residual lignin were already reacted by substantial amount of chlorine. About 80% of chlorine was chlorination.

MISC

Books etc

  • 小池, 孝良, 中村, 誠宏, 宮本, 敏澄 (Contributor【コラム４・４】ヘミセルロースに含まれる糖類)
    農山漁村文化協会 2021/04 (ISBN: 9784540122101) 191p p.87
  • 石井, 忠, 石水, 毅, 梅澤, 俊明, 加藤, 陽治, 岸本, 崇生, 小西, 照子, 松永, 俊朗 (Contributor2.1.3 31P NMRによるリグニン水酸基の定量)
    弘前大学出版会 2016/02 (ISBN: 9784907192211) xi, 403p p.65-70
  • Encyclopedia of polymeric nanomaterials
    Yasumitsu Uraki, Keiichi Koda (ContributorLignin)
    978-3-642-36199-9 2015 (ISBN: 9783642361999) 2672 pp.1073-1080
  • セルロースナノファイバーの調製、分散・複合化と製品応用
    浦木康光, 游 翔宇, 幸田圭一 (Contributorエレクトロスピンイング法によるセルロースナノファイバーの調製とその特性)
    ㈱技術情報協会 2015/01 (ISBN: 9784861045660) 535 135-139
  • 坂, 志朗 (第5章 リグニンの利用の現状と展望 1 リグニンを原料としたポリエステル)
    シーエムシー出版 2013/07 (ISBN: 9784781308050) v, 244p p.145-152
  • Functional materials from renewable sources
    Yasumitsu Uraki, Keiichi Koda, Tatsuhiko Yamada, Chihiro Oikawa, Tomohiro Aso (ContributorNovel functions of nonionic, amphiphilic lignin derivatives)
    American Chemical Society, Washington, DC, USA 2012 (ISBN: 9780841227880) 361 243-254
  • Sustainable Production of Fuels, Chemicals, and Fibers from Forest Biomass
    Keiichi Koda, Satoshi Kubo, Yasumitsu Uraki (ContributorChemicals from lignin based on thermal fusibility and amphiphilicity)
    American Chemical Society, Washington, DC, USA 2011 (ISBN: 9780841226432) 526 261-277
  • 中村 太士, 小池 孝良 (Contributor【コラム】リグニンを調べる)
    朝倉書店 2005/09 (ISBN: 425447038X) 218 162

Presentations

  • Development of Lignin-based Bioploymers for Sustainable Use of Woody Biomass  [Invited]
    Keiichi Koda
    The First International Conference of Lignocellulose in conjunction with The 10th International Symposium for Sustainable Humanosphere 2021 (ICON-LIG & ISSH 2021)  2021/09
  • Woody Biomass Refinery -Its Significance and Future Perspective-  [Invited]
    Keiichi Koda
    Asia Pacific Regional Meeting 2021 (APRM 2021)  2021/06
  • Lignin-based flexible film as a separator for electric double-layer capacitor Preparation of lignin-based activated carbon fiber and its electrical application  [Invited]
    Keiichi Koda, Atsushi Kobota, Tomofumi Isozaki, Tatsuhiko Yamada, Yasumitsu Uraki
    5th ISETPP & 3rd IPEC  2016/11  Guangzhou, China  South China University of Technology
  • 幸田圭一
    第25回時計台サロン 農学部に聞いてみよう  2015/04  札幌時計台2F演武場（札幌市）  北海道大学農学部／農学院／農学研究院
  • KODA, Keiichi
    北海道大学総合博物館 土曜市民セミナー  2013/10  北大総合博物館１F「知の交流」コーナー（札幌市）  北海道大学総合博物館
  • Challenging Adventure on Lignin Chemistry  [Invited]
    KODA, Keiichi
    Invited Lecture at Mulawarman University  2006/09  Samarinda, Indonesia  Mulawarman University
  • リンのNMRによるリグニン官能基の視覚化  [Invited]
    幸田圭一
    セルロース学会北海道・東北支部主催講演会『木質バイオマスの化学的利用－育種から先端利用まで－』  2005/11  北大農学部（札幌市）  セルロース学会北海道・東北支部
  • ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY. Vol. 229. 1155 16TH ST, NW, WASHINGTON, DC 20036 USA: AMER CHEMICAL SOC, 2005.  [Not invited]
    D.Argyropoulos, A. Gaspar, K. Koda
    Abstracts of Papers of the Amirian Chemical Society Vol. 229. 1155 16TH ST, NW, WASHINGTON, DC 20036 USA: AMER CHEMICAL SOC, 2005.  2005  San Diego  ACS
  • 製紙用パルプの塩素系漂白で生成する高分子有機塩素化合物の微生物分解挙動  [Invited]
    幸田圭一
    北海道科学技術ネットワークセッション-若手研究者研究成果発表会・交流会-  2003/03  かでる2・7（札幌市）  〔財〕北海道科学技術総合振興センター
  • クラフトパルプの塩素漂白過程で副生する環境有害物質の追跡  [Invited]
    幸田圭一
    平成12年度繊維学会北海道紙パルプ技術懇談会講演会  2001/03  北海道大学百年記念会館（札幌市）  繊維学会北海道紙パルプ技術懇談会

Association Memberships

  • The Lignin Society   Japan Wood Research Society   繊維学会   日本腐植物質学会   ヨウ素学会   木質炭化学会   高分子学会   紙パルプ技術協会   セルロース学会   Fiber Science and Technology   Japan Humic Substances Society   The Society of Iodine Science   The Wood Carbonization Research Society   The Society of Polymer Science, Japan   Japan TAPPI   The Cellulose Society of Japan   The Japan Wood Research Society   

Research Projects

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2018/04 -2021/03 
    Author : Uraki Yasumitsu
     
    This study clearly demonstrated the effect of hemicelluloses on ligninfication through lignin formation in the artificial polysaccharide matrices; xylan contributed to lignin formation and generation of 8-O-4' interunitary linkage, which was a major linkage in native lignin, while glucomannan inhibited lignin formation. In addition, xyloglucan, which located only at primary wall of tree, was found to enhance the frequency of 5-5' interunitary linkage. From the analysis of solution structure for isolated lignins by using size-exclusion chromatograph equipped with multi-angle laser light scattering detector, 5-5' linkage was found to be closely related to the densed structure, especially much compact structure of lignin fraction with larger molar mass compared to that with small molar mass.
  • Extended analysis of interunitary linkages of lignin by improved alkaline nitrobenzene oxidation
    Japan Society for the Promotion of Science (JSPS)：Grant-In-Aid for Scientific Research (C)
    Date (from‐to) : 2018/04 -2021/03 
    Author : KODA, Keiichi
  • リグニンは落葉の生分解を強く規定するか？
    Japan Society for the Promotion of Science (JSPS)：Grant-In-Aid for Scientific Research (C)
    Date (from‐to) : 2015/04 -2018/03 
    Author : 幸田圭一
  • 木材細胞壁模倣多糖類マトリックス中でのリグニンの形成とその構造決定因子の解明
    Japan Society for the Promotion of Science (JSPS)：Grant-In-Aid for Scientific Research (A)
    Date (from‐to) : 2014/04 -2018/03 
    Author : Yasumitsu Uraki
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2013/04 -2016/03 
    Author : MIYAMOTO Toshizumi, KODA Keiichi, SHIGETOMI Kengo
     
    We isolated litter-decomposing fungi capable of producing active extracellular phenoloxidases at 0 °C from decomposing litter under snow cover in the forests. Molecular phylogenetic analysis and identification of extracellular enzymes of these fungi were conducted. It was revealed that the fungi involved in lignin decomposition under snow cover were consisted of various taxonomic groups inhabiting in litter of various plant species. These fungi were isolated from beginning of snow cover period to snow melting season. Lac, LiP, and MnP active at 4°C were produced from the mycelia of these fungi. A new method to determine lignin content of decomposing leaf litter was also developed. Loss of lignin in litter during the snow cover period was monitored by the new method. Lignin was lost at higher rate than previously reported.
  • 公募研究課題３「木質リグニンからの材料製造技術の開発」
    農林水産省 農林水産技術会議：委託プロジェクト研究「農山漁村におけるバイオ燃料等生産基地創造のための技術開発」（平成24年度～27年度）
    Date (from‐to) : 2012/04 -2016/03 
    Author : 大原誠資
  • 広葉樹の道管相互壁孔に常在する抽出成分の同定と通水への影響解析
    Japan Society for the Promotion of Science (JSPS)：Grant-In-Aid for Scientific Research (C)
    Date (from‐to) : 2011/04 -2015/03 
    Author : Yuzo Sano
  • 冷温帯林における積雪下でのリター分解菌類群集の組成とその分解酵素活性
    Japan Society for the Promotion of Science (JSPS)：Grant-In-Aid for Scientific Research (C)
    Date (from‐to) : 2009/04 -2012/03 
    Author : Toshizumi Miyamoto
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    Date (from‐to) : 2009 -2011 
    Author : URAKI Yasumitsu, TAMAI Yutaka, KODA Keiichi, HIRAI Takuro, SUGIYAMA Junji
     
    In this study, hemicellulose-adsorbed honeycomb-patterned cellulose films termed as artificail wood cell wall were developed to investigate the function of hemicelluloses in wood cell wall and to develop the cell culture for liver cells. Tensile strength and its modulus of the cellulosic films were enhanced by the adsorption of hemicelluloses, xylan and arabinogalactan (AG). Xylan adsorption and its tensile modulus were improved by microwave irradiation. We judged proposed theory for the elucidation of deformation mechanism of wood cross-scetion upon the mechanical stress from the tensile properties of honeycomb-patterned films. As a result, the theory of bending-stretching model was suitable for the elucidation, and xylan-adsorbed film showed more fitting to the theory. In addition, we evaluated AG-adsorbed honeycomb-patterned film as a culture substrate for mouse liver cells. The films with small pores were found to be a new type candidate substrate for the culture. On the other hand, the films with larger pores would be suggested to be a plate for cell array, but the number of attached cell was so small. For the industrial application, this problem should be overcome.
  • Identification of extractives occurring in vessel perforation in hardwood
    Cooperative Research
    Date (from‐to) : 2011
  • 木質バイオマスの利活用を指向したリグニン単位間結合の新規切断方法の開発
    経常研究
    Date (from‐to) : 2005 -2010 
    Author : 幸田圭一
  • Biodegradation and Environmental Fate of Lignin and Lignin-like Substances in Forest Ecosystem
    Ordinary Research
    Date (from‐to) : 2006
  • A Novel Procedure for Ether Cleavage of Lignin Interunit Linkages under Mild Reaction Conditions -For Complete Utilization of Woody Biomass-
    Ordinary Research
    Date (from‐to) : 2005
  • 製紙用パルプ漂白排水成分の生分解性ならびに環境毒性の総合的評価系の確立
    The Ministry of Education,Culture,Sports,Science and Technology (MEXT)：Grant-In-Aid for Scientific Research (KAKENHI)
    Date (from‐to) : 2003/04 
    Author : Keiiichi Koda
     
    (※North Carolina State Universityでの博士研究員（2003年7月～2005年5月）に内定したため、交付決定後、辞退)
  • パルプの塩素漂白で生成する高分子塩素化合物の代謝モデル系の確立
    ノーステック財団（北海道科学技術振興財団）：平成13年度一般研究奨励事業 若手研究者研究奨励補助金
    Date (from‐to) : 2001/04 -2002/03 
    Author : 幸田圭一

Industrial Property Rights

  • 特開2019-108441(P2019-108441A).:組成物  2019/07/04
    浦木康光, 幸田圭一, 今野晴男  国立大学法人北海道大学;日本製紙株式会社

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