2004 年 27 巻 4 号 p. 261-266
Sixteen different operational conditions of a photobioreactor for both organic wastewater treatment and material recovery were examined to determine the optimal condition(s) for the proliferation of purple nonsulfur bacteria (PnSB). Bacterial community changes were analyzed by denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH). FISH was applied to detect PnSB and quantify their population. FISH results revealed that a high PnSB ratio was obtained under the conditions that deprivation of dissolved oxygen and restraint of oxygenic phototrophs were required. An infrared filter effectively suppressed oxygenic phototrophs and enhanced PnSB. Higher PnSB ratio was obtained at a low light intensity (260 lux and 650 lux) than at a high light intensity (5800 lux). Both DGGE and FISH results consistently showed that Rhodopseudomonas palustris, which may originate from spiked activated sludge, is more competitive to chemoheterotrophs than Rhodobacter sphaeroides precultivated as pure culture.