酸生成菌共存下での酢酸資化性メタン生成菌の付着・凝集挙動

摘要

Adhesion and coaggregation phenomena of acetate-utilizing methanogens in the methane fermentation process were examined. The surface characteristics of three acidogens enriched from the anaerobic sludge and the pure cultures of Methanosarcina barken and Methanosaeta concilli were estimated. As a result, the selective adhesion phenomena of acetate-utilizing methanogen onto the bamboo charcoal could be explained by the electrostatic interaction and the change of free energy of interaction between microbes and support materials. The non-washed proteolytic bacteria and Methanosarcina barken were found to coaggregate rapidly even though the change of free energy of interaction was positive. It is guessed that these two microbes coaggregate with biological interaction because proteolytic bacteria produce hydrogen which is the substrate of Methanosarcina barken. The proteolytic bacteria enriched in this study can be expected to be used as bioflocculant that rapidly forms the granule of acetate-utilizing methanogens.%メタン発酵プロセスは，古くから有機性廃棄物からバイオエネルギーを抽出できる技術として知られているが，近年の「循環型社会形成推進基本法」をはじめとするリサイクル法の整備により再注目されている。しかし，メタン発酵プロセスは，発酵効率が低い，処理速度が遅いなどの課題を抱えているのが現状である。これらの問題を解決するには，メタン発酵プロセスにおいて律速段階となっている酢酸からメタンへの変換に関わる酢酸資化性メタン菌－）の高密度化が必要不可欠である。