報告書番号

U91010

タイトル（和文）

石炭の生物加工－４－石炭中の無機硫黄を脱硫する微生物の分離と選抜

タイトル（英文）

BIOPROCESSING OF COAL-4- ISOLATION AND SELECTION OF BACTERIA TO REMOVIEG INORGANIC SULFUR FROM COAL

概要 （図表や脚注は「報告書全文」に掲載しております）

石炭をクリーンな石油代替エネルギーとして利用するため，微生物を用いた燃焼前脱硫法の開発を目標とし，無機硫黄脱硫微生物の分離と選抜を試みた。硫酸第一鉄および黄鉄鉱を用いた２種類の分離法によって，それぞれ中温性細菌２３株，中温性細菌２２株および高温性細菌１株を分離した。これら中温性細菌の中から，鉄酸化活性または黄鉄鉱からの可溶性鉄，硫酸根の浸出速度が高い５株を選抜した。選抜された中温性細菌５株および高温性細菌１株は，対照株（ＴｈｉｏｂａｃｉｌｌｕｓｆｅｒｒｏｏｘｉｄａｎｓＡＴＣＣ２３２７０）と同等以上の黄鉄鉱浸出速度を持つことから石炭からの無機硫黄脱硫に有効な菌株と考えられた。また，選抜された中温性細菌５株は，すべてＴｈｉｏｂａｃｉｌｌｕｓ属，高温性細菌は，Ａｒｃｈａｅｏｂａｃｔｅｒｉａに属するものと推定された。

概要 （英文）

COAL IS AN ABUNDANT AND ECONOMIC ENERGY SOURCE AND IT IS EXPECTED TO BE A VIABLE ALTERNATIVE TOOIL. HOWEVER,SULFUR IN COAL IS RELEASED INTO THE ENVIRONMENT AS SULFUR DIOXIDE BY COMBUSTION. AT PRESENT,SULFUR DIOXIDE IS REMOVED FROM FLU GAS BY DESULFURIZATIONEQUIPMENT. IF SULFUR IN COAL COULD BE REMOVED BEFORE COMBUSTION,HIGH-SULFUR COALS,WHICH ARE NOT CURRENTLY USED,WOULD BE AVAILABLE FOR PLANTS.MICROBIAL TECHNOLOGY COULD REMOVE SULFUR FROM COAL BEFORE COMBUSTION. THIS PAPER REPORTS THE ISOLATION AND SELECTION OF BACTERIA THAT CAN REMOVE INORGANIC SULFUR FROM COAL. ISOLATION WAS CARRIED OUT BY TWO METHODS:EMPIRICALLY(METHOD 1;MEDIUM CONTAINS FESO4 AS ENERGY SOURCE),AND BY ANEWLY-DEVELOPED METHOD (METHOD 2:MEDIUM CONTAINS FES2 AS ENERGY SOURCE). BACTERIA WERE ISOLATED FROM SOILS AT COAL-STORAGE SITES,MINES,VOLCANIC AREAS AND HOT SPRINGS. TWENTY-THREE MESOPHILES WERE ISOLATED BY METHOD 1;TWENTY-TWO MESOPHILES AND ONE THERMOPHILE WERE ISOLATED BY METHOD 2. DESULFURIZATION ACTIVITIES INDICATED AS THE FERROUS IRON OXIDATION RATE OR PYRITE OXIDATION RATE WERE TESTED FOR ALL THE MESOPHILES. FIVE MESOPHILES AND THE THERMOPHILE HAD A HIGHER PYRITE OXIDIZING ACTIVITY THAN THE TYPE STRAIN(THIOBACILLUS FERROOXIDANS ATCC 23270). THESE SIX ISOLATES REMOVE INORGENIC SULFUR FROM COAL EFFECTIVELY. THE FIVE MESOPHILES BELONG TO THE GENUS THIOBACILLUS AND THE THERMOPHILE IS AN ARCHAEOBACTERIA.

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