NO_3^-およびNO_2^-を電子受容体としたメタノール脱窒リアクターの運転とその脱窒細菌の遺伝子の解析

概要

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We compared the denitrification rates and bacterial denitrification genes (nirK and nirS) between denitrification processes using NO2- and NO3-. We operated a sequencing batch reactor (SBR) for denitrification using activated sludge. The SBR was first fed with NO3- (Run 1), and the electron acceptor was then changed to NO2- (Run 2). Methanol was fed as the major electron donor through out the operational period (64 days). Denitrification rates (mg-N · g-MLSS-1 · h-1) were measured at regular intervals. Results showed that the maximum denitrification rates were more than 40 mg-N · g-MLSS-1 · h-1 irrespective of electron acceptor type. However, it takes 12 days to reach the maximum denitrification rate after changing the electron acceptor to NO2-. The results of the cloning analysis of nirK and nirS implied that the lag time was attributable to bacterial population shifts, because the nirK and nirS detected at Run 1 were phylogenetically different from those at Run 2. However, the changes in the total copy numbers of nirK or nirS could not explain the changes in the denitrifying rates.
社団法人　日本水環境学会の論文
2008-05-10