Kenichi Hashiguchi
Ajinomoto
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Featured researches published by Kenichi Hashiguchi.
Bioscience, Biotechnology, and Biochemistry | 2002
Shunichi Suzuki; Masakazu Sugiyama; Yasuhiro Mihara; Kenichi Hashiguchi; Kenzo Yokozeki
Microorganisms capable of producing xylitol from D-arabitol were screened for. Of the 420 strains tested, three bacteria, belonging to the genera Acetobacter and Gluconobacter, produced xylitol from D-arabitol when intact cells were used as the enzyme source. Among them, Gluconobacter oxydans ATCC 621 produced 29.2 g/l xylitol from 52.4 g/l D-arabitol after incubation for 27 h. The production of xylitol was increased by the addition of 5% (v/v) ethanol and 5 g/l D-glucose to the reaction mixture. Under these conditions, 51.4 g/l xylitol was obtained from 52.4 g/l D-arabitol, a yield of 98%, after incubation for 27 h. This conversion consisted of two successive reactions, conversion of D-arabitol to D-xylulose by a membrane-bound D-arabitol dehydrogenase, and conversion of D-xylulose to xylitol by a soluble NAD-dependent xylitol dehydrogenase. Use of disruptants of the membrane-bound alcohol dehydrogenase genes suggested that NADH was generated via NAD-dependent soluble alcohol dehydrogenase.
Journal of Biotechnology | 2011
Keita Fukui; Chie Koseki; Yoko Yamamoto; Jun Nakamura; Ayako Sasahara; Reiko Yuji; Kenichi Hashiguchi; Yoshihiro Usuda; Kazuhiko Matsui; Hiroyuki Kojima; Keietsu Abe
Corynebacterium glutamicum produces succinate from glucose via the reductive tricarboxylic acid cycle under microaerobic and anaerobic conditions. We identified a NCgl2130 gene of C. glutamicum as a novel succinate exporter that functions in succinate production, and designated sucE1. sucE1 expression levels were higher under microaerobic conditions than aerobic conditions, and overexpression or disruption of sucE1 respectively increased or decreased succinate productivity during fermentation. Under microaerobic conditions, the sucE1 disruptant sucE1Δ showed 30% less succinate productivity and a lower sugar-consumption rate than the parental strain. Under anaerobic conditions, succinate production by sucE1Δ ceased. The intracellular succinate and fructose-1,6-bisphosphate levels of sucE1Δ under microaerobic conditions were respectively 1.7-fold and 1.6-fold higher than those of the parental strain, suggesting that loss of SucE1 function caused a failure of succinate removal from the cells, leading to intracellular accumulation that inhibited upstream sugar metabolism. Homology and transmembrane helix searches identified SucE1 as a membrane protein belonging to the aspartate:alanine exchanger (AAE) family. Partially purified 6x-histidine-tagged SucE1 (SucE1-[His](6)) reconstituted in succinate-loaded liposomes clearly demonstrated counterflow and self-exchange activities for succinate. Together, these findings suggest that sucE1 encodes a novel succinate exporter that is induced under microaerobic conditions, and is important for succinate production under both microaerobic and anaerobic conditions.
Applied and Environmental Microbiology | 2015
Yoshinori Tajima; Yoko Yamamoto; Keita Fukui; Yousuke Nishio; Kenichi Hashiguchi; Yoshihiro Usuda; Koji Sode
ABSTRACT Lowering the pH in bacterium-based succinate fermentation is considered a feasible approach to reduce total production costs. Newly isolated Enterobacter aerogenes strain AJ110637, a rapid carbon source assimilator under weakly acidic (pH 5.0) conditions, was selected as a platform for succinate production. Our previous work showed that the ΔadhE/PCK strain, developed from AJ110637 with inactivated ethanol dehydrogenase and introduced Actinobacillus succinogenes phosphoenolpyruvate carboxykinase (PCK), generated succinate as a major product of anaerobic mixed-acid fermentation from glucose under weakly acidic conditions (pH <6.2). To further improve the production of succinate by the ΔadhE/PCK strain, metabolically engineered strains were designed based on the elimination of pathways that produced undesirable products and the introduction of two carboxylation pathways from phosphoenolpyruvate and pyruvate to oxaloacetate. The highest production of succinate was observed with strain ES04/PCK+PYC, which had inactivated ethanol, lactate, acetate, and 2,3-butanediol pathways and coexpressed PCK and Corynebacterium glutamicum pyruvate carboxylase (PYC). This strain produced succinate from glucose with over 70% yield (gram per gram) without any measurable formation of ethanol, lactate, or 2,3-butanediol under weakly acidic conditions. The impact of lowering the pH from 7.0 to 5.5 on succinate production in this strain was evaluated under pH-controlled batch culture conditions and showed that the lower pH decreased the succinate titer but increased its yield. These findings can be applied to identify additional engineering targets to increase succinate production.
Archive | 1995
Kenichi Hashiguchi; Hiroko Kishino; Nobuharu Tsujimoto; Hiroshi Matsui
Archive | 2004
Kenichi Hashiguchi; Yuta Nakai; Hisao Itou
Archive | 1995
Fusao Tomita; Atsushi Yokota; Kenichi Hashiguchi; Masako Ishigooka; Osamu Kurahashi
Archive | 1996
Katsunori Kobayashi; Shigeru Yamanaka; Kiyoshi Miwa; Shunichi Suzuki; Yuzuru Eto; Yuko Tanita; Kenzo Yokozeki; Kenichi Hashiguchi
Bioscience, Biotechnology, and Biochemistry | 1998
Katsunori Kobayashi; Kenichi Hashiguchi; Kenzo Yokozeki; Shigeru Yamanaka
Archive | 1995
Fusao Tomita; Atsushi Yokota; Kenichi Hashiguchi; Masako Ishigooka; Osamu Kurahashi
Archive | 1989
Katsuaki Sato; Eriko Yoshino; Kenichi Hashiguchi; Hitoshi Enei