Hydrogen and Methane Fermentation of Rice Straw and Kitchen Leftovers

Sequential fermentations for hydrogen and methane were carried out at 37℃ with a mash containing rice straw obtained from horse feces and kitchen leftovers as substrates by the sequential addition of fresh horse feces and acclimated methane sludge. The efficiency of the fermentations was improved by pretreatment of the substrates with 0.16% NaOH at 123℃ for 20 min and with 0.18% cellulolytic and hemicellulolytic enzymes at 30℃ at pH 4.5 for 3 days. This treatment liberated 12% of sugar materials from the substrates and doubled the volume of gas evolved in the fermentations. The volume of hydrogen evolved in 4 days from the substrates supplemented with 100 mg of urea by the microbes in 2 g of fresh horse was 338 ml, representing 13.8% of the total volume of gas evolved. The volume of methane evolved in the following 12 days on addition of 15 ml of acclimated sludge was 604 ml. The volume percentage of methane in the gas was 58% at 5 days, increasing to 82% at 12 days. The COD of the supernatant of the mash decreased from the initial 8,400 to 528 ppm at the end of the fermentation. The amount of carbon in the gas evolved was calculated to represent 38.3% of the carbon contained in the two substrates. A small amount of acetic acid was accumulated in the mash during the hydrogen fermentation, while large amounts of volatile acids were accumulated in the mash during the methane fermentaion.Mannitol, sorbitol, lactate adn gluconate were good substrates for hydrogen evolution by fresh horse feces; butyric and valeric acids were accumulated in the mash.

収集根拠 : NII-ELS
資料形態 : テキストデータ
コレクション : 国立国会図書館デジタルコレクション > 電子書籍・電子雑誌 > 学術機関 > 学協会
著者所属: Faculty of Science, Osaka City University
著者所属: Faculty of Science, Osaak City University
著者所属: Research Center, Osaka Gas Co. Ltd.,