Shiho Takahashi

Bio: Shiho Takahashi is an academic researcher from University of Tsukuba. The author has contributed to research in topics: Lignin & Polyethylene glycol. The author has an hindex of 6, co-authored 20 publications receiving 132 citations. Previous affiliations of Shiho Takahashi include University of New Brunswick.

Isolation and Thermal Characterization of Softwood-Derived Lignin with Thermal Flow Properties

Abstract: A potential alternative biorefinery platform, in which high quality lignin is the main product of the process, is demonstrated. The polyethylene glycol (PEG)-modified softwood lignin (glycol lignin, GL) was isolated from Japanese cedar by acid-catalyzed PEG solvolysis, where liquid PEG with varying polymer chain length was used as the solvolysis reagent with a small amount of acid catalyst. The isolated glycol lignin had the weight-average molecular weight of 4000–7000 and exhibited a viscous thermal flow property, which is impossible for industrial softwood lignin without further processing steps. Thermal analyses, such as thermomechanical analysis (TMA) and capillary flow tester rheometer (CFT), proved to be sensitive techniques for determination of thermal flow behavior. The lignin yield and solid residue (mostly cellulosic residue), respectively, of 28%–31% and 36%–38% (dry wood basis) were obtained from PEG200 solvolysis with 0.5%–0.7% acid catalyst. The results indicated the effectiveness of the one...

Performance of Softwood Soda-Anthraquinone Lignin as Water-Reducing Chemical Admixture in Concrete

Abstract: We have attempted to establish a new process for producing a concrete chemical admixture prepared with by-product lignin of bioethanol production. In our pretreatment process of bioethanol production, soda-anthraquinone (AQ) cooking was applied to remove lignin from softwood chips. Soda-AQ lignin was recovered as precipitate by acidifying the black liquor. Five kinds of soda-AQ lignin were isolated by selecting the pH value of the precipitation. Each of the isolated soda-AQ lignins was used in the mortar fluidity test as concrete admixture. With the exception of the soda-AQ lignin at higher pH (pH 10.5) precipitation, the isolated lignin gave about two times’ higher mortar flow values than that of the widely used commercial lignosulfonate admixture. Size exclusion chromatography (SEC) data showed that the isolated lignin at higher pH value gave higher molecular weight. Functional group chemical analysis suggested that the isolated lignin of lower molecular weight had a higher phenolic hydroxyl gr...

Removal of Acetic Acid from Spent Sulfite Liquor Using Anion Exchange Resin for Effective Xylose Fermentation with Pichia stipitis

Abstract: Acetic acid is one of the major inhibitors of spent sulfite liquor (SSL) fermentation for ethanol production. The objective of this study was to remove acetic acid from hardwood SSL using anion exchange resin in order to achieve effective fermentation with Pichia stipitis CBS6054. Lignosulfonate, as well as sulfate and sulfite ions in the SSL hindered the removal of acetic acid by anion exchange resins. CaO treatment was an effective method for removing these materials from SSL, which facilitated the removal of acetic acid in the subsequent ion exchange resin treatment. A two-stage strong base ion exchange resin (OH- form) treatment removed approximately 90% of the acetic acid from CaO-treated SSL, which decreased the acetic acid concentration to less than 1 g/L. The combined treatment of CaO and ion exchange resin treatments in a relatively short time achieved the selective removal of acetic acid from SSL and significantly increased the ethanol production from SSL.

Advantage of Acid Sulfite Cooking as Processes of Bioethanol Production

Abstract: マグネシウムベースの酸性サルファイト廃液（SSL）中に単糖を高収率で得ることを目的とし，カラマツ（Larix leptolepis）材，アカシア（Acacia mearnsii）材，およびタケ（Phyllostachys pubescens）材の酸性サルファイト蒸煮処理を行い，炭水化物の溶出挙動を詳細に検討した。また，針葉樹材サルファイトパルプの酵素糖化性が優れている原因を明らかにするため，セルラーゼのパルプへの吸着の挙動について調査した。酸性サルファイト蒸煮をpH1．4および8時間で行った時，カラマツSSLのグルコース含有量は7．7％であり，アカシアSSLのグルコース含有量より高かった。カラマツ材グルコマンナンの溶出は，アカシア材キシランに比べて遅く，また溶出した単糖およびオリゴ糖の分解の速度も遅いということが明らかとなった。また，カラマツ材酸性サルファイトパルプの酵素糖化残さ中のリグニンに対する酵素吸着量は，30―80FPU／lignin gであり，アルカリパルプの吸着量（100―130FPU／lignin g）に比べて低かった。針葉樹材サルファイトパルプの酵素糖化性が優れている原因の一つは，パルプ中の残留リグニンの酵素吸着量が小さいためであると推定される。針葉樹材では，pH1．4の短時間の蒸解で得られたパルプを酵素により加水分解することで，効率的に単糖が得られると期待できる。

Improvement of Ethanol Fermentation from Oligosaccharides in Spent Sulfite Liquor with Pichia stipitis by Combined Calcium Oxide and Ion Exchange Resin Treatments

Abstract: The objective of this study was to develop an effective method for the removal of inhibitory compounds without decreasing oligosaccharides in spent sulfite liquor (SSL). The oligosaccharide fermentation was subsequently conducted by using Pichia stipitis, which is one of the feasible strains that can produce ethanol from oligosaccharides. The effect of inhibitory compounds on ethanol fermentation from cellobiose by P. stipitis was investigated. No ethanol was produced from cellobiose in the presence of more than 5 g/L of acetic acid. At 1 g/L of acetic acid, 2.6 g/L of ethanol was obtained after 40 h of fermentation. The removal of acetic acid in the SSL by the combined CaO and ion exchange resin treatments was also studied. The acetic acid concentration of softwood SSL was decreased from 5.2 to 0.9 g/L without decreasing oligosaccharides concentration by the combined method. Finally, the improvement of ethanol fermentation from oligosaccharides in the SSL by using the combined CaO and ion exchange resin treatments was studied. 1.3 g/L of ethanol was obtained from the SSL treated by the combined methods, while 6.5 g/L of total oligosaccharides were consumed. No ethanol was obtained from the untreated SSL.

History and future of world's most advanced biorefinery in operation

Abstract: Running a biomass biorefinery based on lignocellulosic feedstock is challenging both from a processing point of view as well as from a market point of view. Continuous process and product development is needed to meet the dynamics in the markets. Borregaard in Sarpsborg Norway is one of the most advanced biorefineries in operation today and has more than 40 years experience of running such a biorefinery. Based on this experience and presence in many markets, new strategies for converting lignocellulosic biomass to biochemicals and biofuels in a sustainable and profitable way has been implemented. The company is loyal to the biorefinery strategy of making the maximum amount of valuable products out of the biomass. Examples of potential new product lines are microfibrillar cellulose (MFC), water soluble specialty lignins from other sources than wood, lignocellulosic ethanol, proteins and sugar based chemicals. Both experience from the long history of running a biorefinery as well as the main development routes for future new bioproducts is analyzed and discussed.

Conversion of technical lignins to functional materials with retained polymeric properties

Abstract: A significant amount of technical lignins is produced in the pulp and paper industries. However, most technical lignins are burned for thermal recycling and a few percent are used as materials, such as lignosulfonate as a dispersant. Native lignin has a highly complex structure and is susceptible to structural variations depending on the pulping process, thus hindering the effective utilization of lignins. The procedures used to convert lignins into functional materials include depolymerization to monomeric fragments followed by re-building to functional materials, and chemical modifications to generate functional polymers with retained polymeric properties. In this paper, the latter is disserted. The characteristics of technical lignins, which include kraft lignin, lignosulfonate, and organosolv lignin, and their conversion to functional materials such as polyesters, polyethers, polyurethanes, etc. and the applications of lignin-based materials in some fields are discussed.

Second Generation Bioethanol Production: On the Use of Pulp and Paper Industry Wastes as Feedstock

Abstract: Due to the health and environment impacts of fossil fuels utilization, biofuels have been investigated as a potential alternative renewable source of energy. Bioethanol is currently the most produced biofuel, mainly of first generation, resulting in food-fuel competition. Second generation bioethanol is produced from lignocellulosic biomass, but a costly and difficult pretreatment is required. The pulp and paper industry has the biggest income of biomass for non-food-chain production, and, simultaneously generates a high amount of residues. According to the circular economy model, these residues, rich in monosaccharides, or even in polysaccharides besides lignin, can be utilized as a proper feedstock for second generation bioethanol production. Biorefineries can be integrated in the existing pulp and paper industrial plants by exploiting the high level of technology and also the infrastructures and logistics that are required to fractionate and handle woody biomass. This would contribute to the diversification of products and the increase of profitability of pulp and paper industry with additional environmental benefits. This work reviews the literature supporting the feasibility of producing ethanol from Kraft pulp, spent sulfite liquor, and pulp and paper sludge, presenting and discussing the practical attempt of biorefineries implementation in pulp and paper mills for bioethanol production.