著者

Hiromi Takada Takane Katayama Toshihiko Katoh

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2019_0020, (Released:2020-02-19)

被引用文献数

13

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Ovomucin, a hen egg white protein, is characterized by its hydrogel-forming properties, high molecular weight, and extensive O-glycosylation with a high degree of sialylation. As a commonly used food ingredient, we explored whether ovomucin has an effect on the gut microbiota. O-Glycan analysis revealed that ovomucin contained core-1 and core-2 structures with heavy modification by N-acetylneuraminic acid and/or sulfate groups. Of the two mucin-degrading gut microbes we tested, Akkermansia muciniphila grew in medium containing ovomucin as a sole carbon source during a 24 h culture period, whereas Bifidobacterium bifidum did not. Both gut microbes, however, degraded ovomucin O-glycans and released monosaccharides into the culture supernatants in a species-dependent manner, as revealed by semi-quantified mass spectrometric analysis and anion exchange chromatography analysis. Our data suggest that ovomucin potentially affects the gut microbiota through O-glycan decomposition by gut microbes and degradant sugar sharing within the community.

著者

早川 利郎 徐 錫元 伊賀上 郁夫

出版者

The Japanese Society of Applied Glycoscience

雑誌

澱粉科学 (ISSN:00215406)

巻号頁・発行日

vol.27, no.3, pp.173-179, 1980-08-31 (Released:2011-07-01)

参考文献数

35

被引用文献数

4 10

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コメ澱粉粒は7~25μ くらいの球形もしくは楕円体を呈し,澱粉粒を構成する澱粉小粒は4~6μ くらいの多角立方体である.1個の澱粉粒は20~60個くらいの澱粉小粒を含んでいる. 新潟県地方に栽培される12品種(もち種を含む)の精製澱粉をSEM観察した結果,一部の澱粉小粒の表面に凹みが観察された.澱粉小粒の形態に関して,品種間による差異は見いだしえなかった. 澱粉小粒中心部のTEM観察では,僅少ではあるが,小粒の中心部は周辺部に比較して,澱粉の一部が分解をうけ,粗構造を呈しているように思われた. 蛋白顆粒は3つの形態が観察された.オスミウム酸によって突起状組織を有するように染色され,径0.5~0.7μ くらいの小球形,中心部が濃く染色され1~3μ くらいの球形,そしてオスミウム酸に均一に染色され,球形もしくは角形で1~3μ くらいのものである. 澱粉小粒は蛋白質性膜物質に包まれており,この膜はオスミウム酸によって染色される蛋白質性顆粒物質に連絡しているのが観察された. 胚乳表層部の澱粉粒には蛋白顆粒が没入しているのが観察された.胚乳中心部においては澱粉粒と澱粉粒の間に蛋白顆粒がくさび状に干渉し,澱粉粒の一部が浸食を受けているように思われる箇所が観察された.

著者

Sosyu Tsutsui Kiyoshi Sakuragi Kiyohiko Igarashi Masahiro Samejima Satoshi Kaneko

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.67, no.1, pp.17-22, 2020-02-20 (Released:2020-02-20)

参考文献数

29

被引用文献数

4

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Sugarcane bagasse is a useful biomass resource. In the present study, we examined the efficacy of ammonia pretreatment for selective release of hemicellulose from bagasse. Pretreatment of bagasse with aqueous ammonia resulted in significant loss of xylan. In contrast, pretreatment of bagasse with anhydrous ammonia resulted in almost no xylan loss. Aqueous ammonia or anhydrous ammonia-pretreated bagasse was then subjected to enzymatic digestion with a xylanase from the glycoside hydrolase (GH) family 10 or a xylanase from the GH family 11. The hydrolysis rate of xylan in bagasse pretreated with aqueous ammonia was approximately 50 %. In contrast, in the anhydrous ammonia-treated bagasse, xylan hydrolysis was > 80 %. These results suggested that anhydrous ammonia pretreatment would be an effective method for preparation of sugarcane bagasse for enzymatic hydrolysis to recover xylooligosaccharides.

著者

Yuya Furushiro Takashi Kobayashi

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2019_0014, (Released:2019-10-29)

被引用文献数

9

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Glucose and fructose were treated in subcritical water in the presence of alkali or alkaline earth metal chlorides. All salts accelerated the conversion of saccharides, and alkaline earth metal chloride greatly promoted the isomerization of glucose to fructose. In contrast, alkali metal salts only slightly promoted this isomerization and facilitated the decomposition of glucose to byproducts such as organic acids. The selectivity of the glucose-to-fructose isomerization was higher at lower conversions of glucose and in the presence of alkaline earth metal chlorides. The pH of the reaction mixture also greatly affected the selectivity, which decreased rapidly at lower pH due to the generated organic acids. At low pH, decomposition of glucose became dominant over isomerization, but further conversion of glucose was suppressed. This result was elucidated by the suppression of the alkali-induced isomerization of glucose at low pH. Fructose underwent decomposition during the treatment of the fructose solution, but its isomerization to glucose was not observed. The added salts autocatalytically promoted the decomposition of fructose, and the reaction mechanism of fructose decomposition differed from that of glucose.

著者

Ken Fukami Daiki Suehiro Motoko Ohnishi

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2019_0013, (Released:2019-10-30)

被引用文献数

8

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We examined the in vitro digestibility of maltobionic acid, obtained from enzymatic oxidation of maltose, its utilization by intestinal bacteria, and its biological effects on the bowel movements in healthy subjects. We found that maltobionic acid is not digested in vitro by saliva, gastric juice, or pancreatic juice. Moreover, it is digested only to a small extent by small intestinal enzymes. Among the 24 strains of intestinal bacteria, maltobionic acid was selectively utilized by Bifidobacterium dentium and Bi. adolescentis. We also evaluated the influence of long-term ingestion of maltobionic acid calcium salt on bowel movements in healthy Japanese women by a randomized, double-blind, placebo-controlled, crossover trial. Thirty-four subjects completed the study, and no adverse events related to the test food were observed. Ten subjects were excluded prior to the efficacy analysis because of conflict with the control criteria; the remaining 24 subjects were analyzed. Intake of test food containing 4 g maltobionic acid for 4 weeks caused a significant increase in the stool frequency, significant improvement in stool form scale and CAS-MT total scores as compared with the placebo group. These results suggest that maltobionic acid is an indigestible carbohydrate and is a promising therapeutic agent for improving the intestinal environment.

著者

Takae Nagasawa Katsuyuki Sato Takafumi Kasumi

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2019_0012, (Released:2019-10-24)

被引用文献数

6

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Lactulose, a keto-type disaccharide widely used in pharmaceuticals and functional foods, is produced by the isomerization of lactose. The organogermanium compound poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) is an effective reaction promoter for the conversion of lactose to lactulose because of its high affinity to ketoses. Herein, an effective method for the continuous production of lactulose syrup was developed using Ge-132 through the alkaline isomerization of lactose in a bench-scale plant. This plant carried out a continuous isomerization process using Ge-132, continuous two-step separation process for separating the sugar and Ge-132, a continuous purification and concentration processes for the lactulose syrup, and separation and purification processes for the recovery of Ge-132. In this bench-scale plant, lactulose-containing syrup (350 g/L lactulose, 92 g/L lactose, and 31 g/L galactose) was prepared. The syrup was produced at a rate of 37.7 mL/h, and the content of residual Ge-132 in the syrup was 2 mg/L. The separation process was a two-step separation system requiring an ordinary electrodialyzer and an electro deionizer, which allowed the separation of more than 99.6 % Ge-132 from the reaction mixture. Moreover, the majority of Ge-132 and sodium hydroxide were recovered through electrodialysis using a bipolar membrane. The proposed system is the first to represent the novel development of an effective continuous production system for lactulose-containing syrup on the basis of the use of organogermanium compounds and incorporation of the electrodialysis technology.

著者

Tomoya Shintani Hirofumi Sakoguchi Akihide Yoshihara Ken Izumori Masashi Sato

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2019_0010, (Released:2019-10-24)

被引用文献数

7

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D-Allose (D-All), C-3 epimer of D-glucose, is a rare sugar known to suppress reactive oxygen species generation and prevent hypertension. We previously reported that D-allulose, a structural isomer of D-All, prolongs the lifespan of the nematode Caenorhabditis elegans. Thus, D-All was predicted to affect longevity. In this study, we provide the first empirical evidence that D-All extends the lifespan of C. elegans. Lifespan assays revealed that a lifespan extension was induced by 28 mM D-All. In particular, a lifespan extension of 23.8% was achieved (p < 0.0001). We further revealed that the effects of D-All on lifespan were dependent on the insulin gene daf-16 and the longevity gene sir-2.1, indicating a distinct mechanism from those of other hexoses, such as D-allulose, with previously reported antiaging effects.

著者

Junko Matsuki Tomoko Sasaki Koichi Yoza Junichi Sugiyama Hideo Maeda Ken Tokuyasu

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2019_0009, (Released:2019-10-24)

被引用文献数

2

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Rice-gel prepared by the following three steps: rice grain cooking, shearing of the cooked rice, and cooling for gel formation, is expected as a novel food ingredient for modification of various food products such as bread and noodles. To meet the demand for high-throughput systems for research and developments on the new rice gels, herein we established a mini-cooking system for preparation of rice gel samples from grains using a small-scale viscosity analyzer (Rapid Visco Analyzer; RVA). Polished rice grains (4 g) were cooked with 22 mL of water in a canister, and the paddle equipped in the canister was rotated at 2,000 rpm for 30 min (80 °C was used as a representative) to shear the cooked rice. The sheared paste was cooled to 10 °C at 160 rpm, and the initial gelation property was evaluated by viscosity analysis within the RVA. Alternatively, the sheared paste was transferred to an acrylic mold and kept at 4 °C for 0, 1, 3, and 5 days for determination of the hardness with a compression test. Compressive forces required to penetrate 20 % thickness for three tested rice cultivars were measured, and the trend of the value shifts during preservation is similar to the corresponding trend obtained in 300-g grain scale laboratory tests, whereas the individual values were halved in the former. This small cooking method could offer a useful assay system for a rapid evaluation in the breeding programs and in the high-throughput screening of additives for the modification of properties.

著者

Sangho Koh Seika Imamura Naoto Fujino Masahiro Mizuno Nobuaki Sato Satoshi Makishima Peter Biely Yoshihiko Amano

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2019_0007, (Released:2019-10-24)

被引用文献数

3

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The carbohydrate esterase family 1 (CE1) in CAZy contains acetylxylan esterases (AXEs) and feruloyl esterases (FAEs). Here we cloned a gene coding for an AXE belonging to CE1 from Irpex lacteus (IlAXE1). IlAXE1 was heterologously expressed in Pichia pastoris, and the recombinant enzyme was purified and characterized. IlAXE1 hydrolyzed p-nitrophenyl acetate, α-naphthyl acetate and 4-methylumbelliferyl acetate, however, it did not show any activity on ethyl ferulate and methyl p-coumarate. We also examined the activity on partially acetylated and feruloylated xylan extracted from corncob by hydrothermal reaction. Similarly, ferulic and p-coumaric acids were not liberated, and acetic acid was only detected in the reaction mixture. The results indicated that IlAXE1 is an acetylxylan esterase actually reacted to acetyl xylan. However, since IlAXE1 was unable to completely release acetic acid esterifying xylopyranosyl residues, it is assumed that acetyl groups exhibiting resistance to deacetylation by IlAXE1 are present in corn cob xylan.

著者

藤本 滋生 黒木 千絵 長倉 暁美 菅沼 俊彦 永浜 伴紀

出版者

The Japanese Society of Applied Glycoscience

雑誌

澱粉科学 (ISSN:00215406)

巻号頁・発行日

vol.33, no.1, pp.34-39, 1986-03-31 (Released:2010-03-16)

参考文献数

37

被引用文献数

1 1

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1. わが国において, いわゆる雑草として最も多くみられるイネ科の草本植物であるチカラシバ, エノコログサ, タイヌビエの3種の種子からそれぞれ澱粉を単離精製した. 収率は頴を含む種子重量に対し, 約16%, 15%, 20%であった.2. 各澱粉につき, 水分, 蛋白質およびリンの分析, 顕微鏡観察, 粒径分布, X線回折, ヨウ素呈色, 生澱粉のグルコアミラーゼによる消化, 膨潤力, 溶解度, アミログラフィーなどの諸項目につき測定し, それぞれの澱粉の特性を考察した.3. 3種の澱粉とも粒は比較的小形で, トウモロコシ澱粉に似た形であった. またほとんどの項目において, おおむねトウモロコシ澱粉に近い性質を示した. ただチカラシバ澱粉の膨潤力がサツマイモ澱粉より大きいこと, およびエノコログサとタイヌビエの澱粉のリン含量がそれぞれ0.127%, 0.114%と高いことなどの特徴がみられた.

著者

海野 剛裕 菅原 正義 中久喜 輝夫 岡田 嚴太郎

出版者

The Japanese Society of Applied Glycoscience

雑誌

澱粉科学 (ISSN:00215406)

巻号頁・発行日

vol.40, no.1, pp.21-27, 1993 (Released:2010-06-28)

参考文献数

12

被引用文献数

4

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β-グルコオリゴ糖のヒト腸内フローラに与える影響について検討した.β-グルコオリゴ糖は,微生物起源のβ-グルコシダーゼの糖転移・縮合反応を有効に利用して製造されたβ-グルコオリゴ糖を主成分とするシラップ(商品名:ゲントース)を用いた.In vitroでの腸内細菌による資化性試験においては,β-グルコオリゴ糖はBifidobacteria, Lactobacilliに選択的に資化された.また資化性試験に用いた4株のClostridium perfringensにはほとんど資化性は認められなかった. さらに,β-グルコオリゴ糖をヒトに投与し,腸内フローラの測定を行った結果では,49/日のβ-グルコオリゴ糖の投与によりBifidobacteriaの菌数が有意(p<0.05)に増加し,その占有率は21.5%にまで増加した.この期間の糞便のpHは投与前後に比較して約0.5pH単位の低下が認められた.また被験者の健康状態については異常なガスの発生および鼓脹感はみられず,約6割の被験者において便通および便の硬さの改善がみられた. 以上の結果からβ-グルコオリゴ糖は49/日の摂取量で有効なBifidobacteriaの増殖因子であること,便性改善効果がある新規な澱粉糖として利用できることが示唆された.

著者

村尾 沢夫 大山 邦夫 村井 英継 後藤 章 松井 良博 福原 健一 宮田 茂一 住田 光夫 荒井 基夫

出版者

The Japanese Society of Applied Glycoscience

雑誌

澱粉科学 (ISSN:00215406)

巻号頁・発行日

vol.26, no.2, pp.157-164, 1979-05-31 (Released:2010-06-28)

参考文献数

19

被引用文献数

1

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Three kinds of amylase inhibitor (S-AI, S-GI and Haim) were obtained from the culture filtrate of Streptomyces sp. S-AI was produced by St, diastaticus subsp, amylostaticus and inhibited glucoamylase and various a-amylases . S-PI consisted., of 6 moles of glucose and 1 mole of unknown substances. The structure of S-AI was discussed. S-GI was a specific inhibitor for exotype glucanase and was produced by St, lavendulae . S-GI inhibited animal invertase, but did not inhibit microbial invertase. Haim was a proteineous inhibitor and produced by, St, griseosporus. Haim inhibited specifically animal a-amylases.

著者

鈴木 綾子

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

vol.46, no.1, pp.65-74, 1999-03-31 (Released:2010-06-28)

参考文献数

22

被引用文献数

1 2

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Starchy materials such as cereals, legumes, tubers, and rhizomes are served as foods through the appropriate processing of cooking, which causes the gelatinization of starch. The gelatinized starch is thermodynamically unstable and tends to retrograde during storage. The retrogradation generally decreases the quality of foods known as the staling of bread and the hardening of cooked rice. Therefore, how to control gelatinization and retrogradation is of prime concern of cereal chemists and technologists. I have been involved in this study for nearly 40 years. As early as 1961 we found that microwave heating was very efficient for the rapid cooking of rice, but the cooked rice rapidly hardened by the retrogradation of starch. This was improved by the addition of a small amount of Takaamylase in cooking. Root vegetables are well known for being unable to become soft through cooking even by continued heating after heating has been suspended for a while halfway through cooking. By a detailed analysis of the gelatinization of starch during cooking, this phenomenon was found to be caused by the enhancement of retrogradation of the partially gelatinized starch by cooling. Furthermore, it was found that the heat-stable materials, including various minerals, enhanced the retrogradation. The relationship between structures and functions was investigated on various kinds of starch such as nagaimo (yam), lotus, arrowhead, taro, bracken, and tapioca used in confectioneries. It was found that starches having a high tendency to retrograde had amylopectin with long chain-length and smaller amylose molecules. For example, tapioca starch showed the lowest retrogradation tendency, and this appeared to be due to the short chain length of amylopectin and large amylose molecules, besides thee low amylose content. The relatively higher retrogradation tendency of potato starch seemed to be due to the long chain length of amylopectin. A clear-cut relationship was found between the phosphate content and the pasting viscosity in potato starch that the higher level of phosphorus gave the higher-pasting viscosities. Kuzu amylopectin showed a relatively low retrogradation tendency because of the medium chain length of amylopectin, but kuzu amylose had a high retrograding tendency because of small molecules. Bracken amylopectin with a similar chain length showed a similar retrograding tendency to that of kuzu. Some taro starches showed similar structures and properties to tapioca starch, and they also had low levels of amylose. The starches found in vegetables used in cuisine on New Year's Day have low retrograding tendencies. Therefore they are suitable for use as preservable foods. Amylose molecules are slightly branched molecules on average, and the branches are mostly short chains, but the function of side chains has not been investigated. We attempted to clarify this function by means of a model experiment on molecules that had incorporated small amounts of maltosyl side chains into linear chains by the reverse action of isoamylase. The results clearly showed that these small amounts of maltose side chains affected a decrease in retrograding tendency.

著者

Naoko Crofts Ayaka Itoh Misato Abe Satoko Miura Naoko F. Oitome Jinsong Bao Naoko Fujita

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2018_005, (Released:2018-12-07)

被引用文献数

16

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Extra-long chains (ELC) of amylopectin in rice endosperm are synthesized by granule-bound starch synthase I encoded by the Waxy (Wx) gene, which primarily synthesizes amylose. Previous studies showed that single nucleotide polymorphisms (SNP) in intron 1 and exon 6 of the Wx gene influences ELC amount. However, whether these SNPs are conserved among rice cultivars and if any other SNPs are present in the Wx gene remained unknown. Here, we sequenced the Wx gene from 17 rice cultivars with S or L-type amylopectin, including those with known ELC content and those originating in China with unique starch properties, as well as typical japonica and indica cultivars. In addition to the two SNPs described above, an additional SNP correlating with ELC content was found in exon 10. Low ELC cultivars (<3.0 %) had thymine at the splicing donor site of intron 1, Tyr224 in exon 6, and Pro415 in exon 10. Cultivars with moderate ELC content (4.1–6.9 %) had guanine at the splicing donor site of intron 1, Ser224 in exon 6, and Pro415 in exon 10. Cultivars with high ELC content (7.7–13.9 %) had guanine at the splicing donor site of intron 1, Tyr224 in exon 6, and Ser415 in exon 10. The chain length distribution pattern of amylopectin was correlated with the amounts of SSIIa found in starch granules and gelatinization temperature, but not with ELC content. The combinations of SNPs in the Wx gene found in this study may provide useful information for screening specific cultivars with different ELC content.

著者

Hideyuki Takahashi Chiharu Yoshida Takumi Takeda

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2018_0007, (Released:2018-12-07)

被引用文献数

5

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Sugars are one of the most important factors determining the taste and texture of asparagus (Asparagus officinalis). In this study, we quantified soluble and insoluble sugars in asparagus spears grown in four different agricultural fields. We measured soil chemical properties in each of the fields, and further investigated the relationship between sugar contents in the spears and soil chemical properties. We found a possible relationship between the contents of glucose and fructose and values of cation exchange capacity, available phosphoric acid, and exchangeable calcium and magnesium in the soil. These findings will be useful information for improving asparagus quality.

著者

稲津 脩 渡辺 公吉 前田 巖 伊藤 恵子 長内 俊一

出版者

The Japanese Society of Applied Glycoscience

雑誌

澱粉科学 (ISSN:00215406)

巻号頁・発行日

vol.21, no.2, pp.115-119, 1974-06-15 (Released:2011-02-23)

参考文献数

12

被引用文献数

12 15

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北海道および本州産の粳米について1969~1971の3ヵ年にわたり,延18品種56試料について,米澱粉のヨウ素親和力およびアミロース含有率を測定した。測定方法はアミロースの基準ヨウ素親和力を19と仮定し,この値を用いて各試料の米澱粉のヨウ素親和力からアミロース含有率を計算した。 1)供試した56試料のアミロース含有率は,90%の信頼区間で18.6~24.8%の範囲にあり,平均21.7%であった。また,北海道産米は21.1~24.5%,平均22.8%であり,本州産米の17.6~21.6%,平均19.5%に比較して平均値で3.3%高かった。しかし,この差が本州と北海道の環境の差によるものか,あるいは品種の遺伝的特性によるものかは明らかでなかった。 2)本州で最高値を示した青森のフジミノリと,北海道で最低値を示した厚真産のほうりゅうは類似の含有率を示した。 3)北海楢内においては,品種,栽培地,年次間にいずれも有意差が認められた。とくに,品種間の分散は栽培地および年次間の分散よりはるかに大きく,アミロース含有率は品種によって最も大きく支配された。その品種間差異は,ゆうなみ> ユーカラ> しおかり>ほうりゅうの関係が有意であった。 4)農林20号はほうりゅうよりさらに低いアミロース含有率を示した。 5)栽培地では泥炭地が高く,また,高温年よりも低温年で高まった。 6)これらのことから,北海道産米の改善の一つの方向として,低アミロース品種の重要性が暗示された。

著者

Haruka Yagi Ryo Takehara Aika Tamaki Koji Teramoto Sosyu Tsutsui Satoshi Kaneko

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2018_0008, (Released:2018-11-05)

被引用文献数

14

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We functionally characterized the GH10 xylanase (SoXyn10A) and the GH11 xylanase (SoXyn11B) derived from the actinomycete Streptomyces olivaceoviridis E-86. Each enzyme exhibited differences in the produced reducing power upon degradation of xylan substrates. SoXyn10A produced higher reducing power than SoXyn11B. Gel filtration of the hydrolysates generated by both enzymes revealed that the original substrate was completely decomposed. Enzyme mixtures of SoXyn10A and SoXyn11B produced the same level of reducing power as SoXyn10A alone. These observations were in good agreement with the composition of the hydrolysis products. The hydrolysis products derived from the incubation of soluble birchwood xylan with a mixture of SoXyn10A and SoXyn11B produced the same products as SoXyn10A alone with similar compositions. Furthermore, the addition of SoXyn10A following SoXyn11B-mediated digestion of xylan produced the same products as SoXyn10A alone with similar compositions. Thus, it was hypothesized that SoXyn10A could degrade xylans to a smaller size than SoXyn11B. In contrast to the soluble xylans as the substrate, the produced reducing power generated by both enzymes was not significantly different when pretreated milled bagasses were used as substrates. Quantification of the pentose content in the milled bagasse residues after the enzyme digestions revealed that SoXyn11B hydrolyzed xylans in pretreated milled bagasses much more efficiently than SoXyn10A. These data suggested that the GH10 xylanases can degrade soluble xylans smaller than the GH11 xylanases. However, the GH11 xylanases may be more efficient at catalyzing xylan degradation in natural environments (e.g. biomass) where xylans interact with celluloses and lignins.

著者

Di Guan Rui Zhao Yuan Li Yoshikiyo Sakakibara Masakazu Ike Ken Tokuyasu

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2018_0006, (Released:2018-11-05)

被引用文献数

5

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Novel bioreactor beads for simultaneous saccharification and fermentation (SSF) of lime-pretreated rice straw (RS) into ethanol were prepared. Genetically modified Saccharomyces cerevisiae cells expressing genes encoding xylose reductase, xylitol dehydrogenase, and xylulokinase were immobilized in calcium alginate beads containing inorganic lightweight filler particles to reduce specific gravity. For SSF experiments, the beads were floated in slurry composed of lime-pretreated RS and enzymes and incubated under CO2 atmosphere to reduce the pH for saccharification and fermentation. Following this reaction, beads were readily picked up from the upper part of the slurry and were directly transferred to the next vessel with slurry. After 240 h of incubation, ethanol production by the beads was equivalent to that by free cells, a trend that was repeated in nine additional runs, with slightly improved ethanol yields. Slurry with pre-saccharified lime-pretreated RS was subjected to SSF with floating beads for 168 h. Although higher cell concentrations in beads resulted in more rapid initial ethanol production rates, with negligible diauxic behavior for glucose and xylose utilization, no improvement in the ethanol yield was observed. A fermentor-scale SSF experiment with floating beads was successfully performed twice, with repeated use of the beads, resulting in the production of 40.0 and 39.7 g/L ethanol. There was no decomposition of the beads during agitation at 60 rpm. Thus, this bioreactor enables reuse of yeast cells for efficient ethanol production by SSF of lignocellulosic feedstock, without the need for instruments for centrifugation or filtration of whole slurry.

著者

Kenji Yamagishi Masakazu Ike Di Guan Ken Tokuyasu

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2018_0003, (Released:2018-11-05)

被引用文献数

7

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Generally, Ca(OH)2 pretreatment of lignocellulosics for fermentable sugar recovery requires a subsequent washing step for calcium removal and pH control for optimized saccharification. However, washing Ca(OH)2-pretreated feedstock with water is considered problematic because of the low solubility of Ca(OH)2 and its adsorption to biomass. In this study, we estimated the availability of carbonated water for calcium removal from the slurry of Ca(OH)2-pretreated rice straw (RS). We tested two kinds of countercurrent washing sequences, four washings exclusively with water (W4) and two washings with water and subsequent two washings with carbonated water (W2C2). The ratios of calcium removal from pretreatment slurry after washing were 64.2 % for the W4 process and 92.1 % for the W2C2 process. In the W2C2 process, 49 % of the initially added calcium was recovered as CaO by calcination. In enzymatic saccharification tests under a CO2 atmosphere at 1.5 atm, in terms of recovery of both glucose and xylose, pretreated, feedstock washed through the W2C2 process surpassed that washed through the W4 process, which could be attributed to the pH difference during saccharification: 5.6 in the W2C2 process versus 6.3 in the W4 process. Additionally, under an unpressurized CO2 atmosphere at 1 atm, the feedstock washed through the W2C2 process released 78.5 % of total glucose residues and 90.0 % of total xylose residues. Thus, efficient removal of calcium from pretreatment slurry would lead to not only the recovery of added calcium but also the proposal of a new, simple saccharification system to be used under an unpressurized CO2 atmosphere condition.

著者

Kazuhiro Chiku Mami Wada Haruka Atsuji Arisa Hosonuma Mitsuru Yoshida Hiroshi Ono Motomitsu Kitaoka

出版者

The Japanese Society of Applied Glycoscience

雑誌

Journal of Applied Glycoscience (ISSN:13447882)

巻号頁・発行日

pp.jag.JAG-2018_0002, (Released:2018-11-05)

被引用文献数

6

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We evaluated the stabilities of kojibiose and sophorose when heated under neutral pH conditions. Kojibiose and sophorose epimerized at the C-2 position of glucose on the reducing end, resulting in the production of 2-O-α-D-glucopyranosyl-D-mannose and 2-O-β-D-glucopyranosyl-D-mannose, respectively. Under weak alkaline conditions, kojibiose was decomposed due to heating into its mono-dehydrated derivatives, including 3-deoxy-2,3-unsaturated compounds and bicyclic 3,6-anhydro compounds. Following these experiments, we propose a kinetic model for the epimerization and decomposition of kojibiose and sophorose by heat treatment under neutral pH and alkaline conditions. The proposed model shows a good fit with the experimental data collected in this study. The rate constants of a reversible epimerization of kojibiose at pH 7.5 and 90 °C were (1.6 ± 0.1) × 10−5 s−1 and (3.2 ± 0.2) × 10−5 s−1 for the forward and reverse reactions, respectively, and were almost identical to those [(1.5 ± 0.1) × 10−5 s−1 and (3.5 ± 0.4) × 10−5 s−1] of sophorose. The rate constant of the decomposition reaction for kojibiose was (4.7 ± 1.1) × 10−7 s−1 whereas that for sophorose [(3.7 ± 0.2) × 10−6 s−1] was about ten times higher. The epimerization reaction was not significantly affected by the variation in the buffer except for a borate buffer, and depended instead upon the pH value (concentration of hydroxide ions), indicating that epimerization occurred as a function of the hydroxide ion. These instabilities are an extension of the neutral pH conditions for keto-enol tautomerization that are often observed under strong alkaline conditions.