報告書番号

U89032

タイトル（和文）

石炭の生物加工－１－～石炭を脱硫する微生物に関する調査～

タイトル（英文）

BIOPRAESSING COAL -1- MICROORGANISMS FOE PROCESSING COAL

概要 （図表や脚注は「報告書全文」に掲載しております）

石炭火力発電における環境対策技術，石炭の新利用技術の開発に資するためバイオテクノロジーを石炭の適用した生物加工について研究動向調査を行った。硫黄酸化細菌の一種，ＴｈｉｏｂａｃｉｌｌｕｓｆｅｒｒｏｘｉｄａｎｓやＳｕｌｆｏｌｏｂｕｓａｃｉｄｏｃａｌｄａｒｉｕｓを用いると，実験室レベルでは約１～２週間で９０％程度の無機硫黄を除去できる。有機硫黄を除去できる微生物は少なく，その除去率も低いことが明らかになった。微生物による石炭の液化は基礎研究段階であり，ガス化はまだ構想の段階である。無機硫黄の除去は微生物の取得が比較的容易で，脱硫効果も高いことから最も実用化に近い研究と考える。

概要 （英文）

COAL WILL PLAY A MORE IMPORTANT ROLE THAN OIL AS AN ENERGY SOURCE. HOWEVER,COAL USAGE FOR POWER GENERATION HAS SOMEPROBLEMS. THERFORE,NEW TECHNOLOGIES FOR DECREASING POLLUTANTS,AND PROCESSING COAL ARE REQUIRED TO EXPAND COAL USAGE IN THE FUTURE. COAL BIOPROCESSING HAS RECENTLY RECEIVED ATTENTION AS ONE SUCH TECHNOLOGY. RESEARCH IS INCREASING ESPECIALLY ON PRECOMBUSION REMOVAL OF SULFUR USING MICROORGANISMS. THIS REPORT SUMMARIZES THE INFORMATION ON MICROORGANISMS FOR COAL BIOPROCESSING. SOME SULFUR-OXIDIZING BACTERIA SUCH AS THIOBACILLUS FERROOXIDANS AND SULOLOBUS ACIDOR ALDARIUS CAN HONGE PYRITE IN COALTO THE WATER-SOLABLE SULFATE ION. THEIR ACTIVITY DEPENDS ON PH,TEMPERATURE,PARTICLE SIZE OF COAL,SLURRY CONCENTRATION,AND STRAIN. UNDER OPTIMUM CONDITIONS IN BENCH-SCALE EXPERIMENTS ABOUT 90% OF INORGANIC SULFUR IN COAL CAN BE REMOVED IN 1 OR 2 WEEKS. ORGANIC SULFUR IS MORE DIFFICULT TO REMOVE THAN INORGANIC SULFUR. VERY FEW STRAINS CAN REMOVE SOME ORGANIC SULFUR. SULFOLOBUS ACIDO CALDARIUS,CAN REMOVE BOTH INORGANIC AND ORGANIC SULFUR SIMULTANEOUSLY. ONE MUTANT STRAIN OF PSEUDOMONAS IS EXCELLENT AT DESULFURIZATION. THESE ORGANISMS ARE SUPERIOR TO OTHERS. SOME FUNGI AND BACTERIA CAN DEGRADE SOME LOW-GRADE COALS INTO WATER-SOLUBLE BLACK LIQUID. THIS PRODUCT CONTAINS ROUGHLY 95% OF THE ORIGINAL ENERGY AND MAY HAVE DECREASED ASH CONTENT. MICROBIAL SOLUBILIZATION IS COUSED BY THE ACTION OF BIOLOGICAL AGENTS SUCH AS ENZYMES RELEASED FROM THE MICROOGANISMS. CONSEQUENTLY RESEARCH ON CELL-FREE REACTION SYSTEMS HAS BEGUN. BIOCONVERSION OF LOW-GRADE COALS TO METHANE GAS HAS BEEN PROPOSED,BUTITIS STILL ONLY AN IDEA. THIOBACILLUS FERROOXIDANS AND SULFOLOBUS ACIDOCALDARIUS CAN REMOVE MOST INORGANIC SULFUR IN BENCH-SCALE EXPERIMENTS. HOWEVER,MORE ADVANCED STUDIES WILL BE REQUIRED ON REACTORS AND PROCESSES FOR COMMERCIAL PLANTS. IT IS VERY DIFFICULT TO REMOVE ORGANIC SULFUR THROUGH BIOPROCESSING,BECAUSE ONLY A FEW GOOD MICROORGANISMS HAVE BEEN FOUND. MICROBIAL LIQUEFACTION AND

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