Abstract
Endotoxins are among the constituents of the outer cell wall of gram-negative bacteria and some
cyanobacteria. Endotoxin, which is known to cause various symptoms in humans typically via intravenous exposure
including fever, diarrhea, and vomiting existed widely in raw water and treated tap water.In this study, we examined
behavior of endotoxin activity in drinking water purification process in a water purification plant employing advanced
water purification process in japan, evaluated endotoxin producing potential of heterotrophic bacteria isolated from
actual biological activated carbon (BAC) filters at the water purification plant, as well as their predominance in the
BAC filter using 16s rRNA gene sequencing analysis.We revealed removal characterization of endotoxin activity in
each drinking water purification process, and proposed a method for controlling endotoxin activity. Thirteen genera
were identified among 105 individual strains obtained from BAC filter and/or its backwashing water samples. The
endotoxin producing capability of each eight genera were also characterized.
