Browsing by Author "Kobayashi, Fumihisa"

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    Additive Effect of Soybean Curd Residue, Okara, for Enhancement of Methane Production from Pretreated Woody Waste
    (2005) Take, Harumi; Mtui, Godliving Y. S.; Kobayashi, Fumihisa; Nakamura, Yoshitoshi
    In order to convert woody waste into methane gas efficiently, the pretreatment effect of steam explosion and the additive effect of soybean curd residue, okara, were clarified. 180 mL of methane gas was obtained from 1 g of steam-exploded Japanese cedar chips at a steam pressure of 4.51 MPa and a steaming time of 5 min while no methane gas was produced from untreated chips. The addition of okara into the chips was attempted and the optimal condition, i.e. C/N of 18, increased the methane gas produced to 315 mL.
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    Degradation of 2,4-Dichlorophenoxyacetic Acid (2,4-D) by Ozonation and TiO2/UV Treatment
    (2007-04) Daidai, Masakazu; Kobayashi, Fumihisa; Mtui, Godliving Y. S.; Nakamura, Yoshitoshi
    The degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was conducted by ozonation, TiO2/UV treatment only, and two-stage treatment of ozonation followed by TiO2/UV treatment. In the case of ozonation, 2,4-D could be degraded and vanished within about 10 min at pH 9 and 20°C, but the TOC value was reduced by only about 40% by 30 min ozonation. In the case of TiO2/UV treatment, about 5 d was needed for complete disappearance of 2,4-D at pH 5 and 20°C. On the other hand, when the two-stage treatment of ozonation plus TiO2/UV treatment was applied, 90% decline of TOC was achieved within about 20 h, i.e., 30 min ozonation and 20 h TiO2/UV treatment thereafter. Furthermore, 90% of chloride ions in 2,4-D were liberated by the two-stage treatment. From a bioassay test of the two-stage treated water by the use of an osteoclasts of goldfish scales or Daphnia magna, it was found that 2,4-D was degraded into harmless substances with little estrogen activity and toxicity.
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    Lignin Peroxidase Production by Phanerochaete Chrysosporium Immobilized on Polyurethane Foam
    (2005-02) Nakamura, Yoshitoshi; Sawada, Tatsuro; Mtui, Godliving Y. S.; Kobayashi, Fumihisa; Kuwahara, Masaaki; Ito, Hiromichi
    Production of lignin peroxidase by a white-rot basidiomycete, Phanerochaete chrysosporium, was investigated experimentally using polyurethane foam as a carrier of immobilized fungal mycelia. The immobilized cell culture using polyurethane foam as a carrier of mycelia yielded significantly greater lignin peroxidase activity than the conventional stationary liquid culture. The effects of operational conditions, such as the kind and number of polyurethane foam cubes, glucose concentration and temperature, on the lignin peroxidase production were examined. Addition of 0.05% Tween 80, 1 mM veratryl alcohol and 1 mM FeSO4-·7H2O greatly improved the production of lignin peroxidase up to 2,700 units/ml culture medium. The lignin peroxidase activity in this culture was about three times larger than that obtained from the culture cultivated in the absence of these additives. Step change incubation lowering the temperature from 37°C to 30°C over an incubation time of three days was carried out for the large scale production of lignin peroxidase, and this incubation gave the highest lignin peroxidase activity 3,800 units/ml culture medium.
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    Novel Extraction Method of Antioxidant Compounds from Sasa Palmata (Bean) Nakai using Steam Explosion
    (2007-10) Kurosumi, Akihiro; Sasaki, Chizuru; Kumada, Kentaro; Kobayashi, Fumihisa; Mtui, Godliving Y. S.; Nakamura, Yoshitoshi
    Antioxidant compounds were extracted from various parts of Sasa palmata (Bean) Nakai, a bamboo plant whose leaves are commonly used to wrap foodstuffs such as Sushi in Japan. Highest concentrations of antioxidant compounds existed in the leaf part of S. palmata. Steam explosion treatment followed by hot water and methanol extractions was used for separating the antioxidant compounds from S. palmata leaf. The steam explosion treatment is the physical–chemical treatment which crushes a sample by sudden reduction of the pressure in reactor to atmospheric pressure after steaming the sample at high temperature and pressures. Sasa palmata leaf was hydrolyzed by steaming and crushed by the rapid decompression. The optimal condition of steam explosion for the effective extraction of antioxidant compounds from S. palmata was determined as a steam of temperature of 250 °C and a steaming time of 1 min. In these conditions 217.41 mg/(g-Sasa leaf) of phenolic compounds and 142.81 mg/(g-Sasa leaf) of radical scavenging activity, that was expressed as butylated hydroxyanisole (BHA), were obtained.
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    Saccharification and Alcohol Fermentation in Starch Solution of Steam-exploded Potato
    (1996-12) Kobayashi, Fumihisa; Sawada, Tatsuro; Nakamura, Yoshitoshi; Ohnaga, Makoto; Mtui, Godliving Y. S.; Ushiyama, Tomoo
    Steam explosion pretreatment of potato for the efficient production of alcohol was experimentally studied. The amount of water-soluble starch increased with the increase of steam pressure, but the amounts of methanol-soluble material and Klason lignin remained insignificant, regardless of steam pressure. The potatoes exploded at high pressure were hydrolyzed into a low molecular liquid starch, and then easily converted into ethanol by simultaneous saccharification and fermentation using mixed microorganisms: an amylolytic microorganism,Aspergillus awamori, and a fermentation microorganism,Saccharomyces cerevisiae. The maximal ethanol concentration was 4.2 g/L in a batch culture at 15 g/L starch concentration, and 3.6 g/L in a continuous culture fed the same starch concentration. In the fed-batch culture, the maximal ethanol concentration increased more than twofold, compared to the batch culture.