Abstract
Denitrification activity behavior and bacterial community structure in a poly-β-hydroxybutyrate (PHB) embedded soil-column reactor were investigated. The influent containing nitrate (NO3-N) was applied in a downward flow. The NO3-N concentration rapidly decreased only in the middle part of the column where PHB was embedded, which indicated that the denitrification activity in the reactor was related to PHB. Influent NO3-N was effectively removed in the reactor following 60 days of continuous operation. The total number of bacteria in the lower and middle parts of the column decreased after 30 days, and then increased again after 60 days; however, the number in the upper part continuously decreased with time. The number of PHB utilizing denitrifiers increased in both the middle and lower parts with time, contributing to denitrification activity in the reactor. From the result of PCR and denaturing gradient gel electrophoresis (PCR-DGGE), the presence of two denitrifing and a few other bacteria were determined, and which suggested of Ralstonia related species played an important role in the denitrification capability of the reactor.
