BIOM ETHAN ATI ON UNDER ELEVATED PRESSURE

抄録

As H₂ and CO₂ can be utilized by methanogenic bacteria, as well as volatile fatty acids such as formic acid, biomethanations of the gaseous substrates and formic acid were carried out under elevated pressure. The pH of the medium was adjusted to the appropriate value for the methanogenic bacteria (pH 6.8) by changing the amount of Na₂CO₃ added to the medium. Biomethanation was not inhibited by elevated partial pressure of the gaseous substrates in the absence of mass transfer limitation of H₂, nor retarded by elevated pressure when formic acid was used as a carbon source. However, the amount of methane evolved from CO₂ and H₂ for 3 days under 101 kPa decreased to 25 % compared with that under 355 kPa in the presence of the mass transfer limitation of H₂. This effect is explained by the mass transfer model.