Quantification of microbial communities in groundwater using real-time PCR

Asano, Takahiro; Sasaki, Yoshito ; Yoshikawa, Hideki

On deep geological environment, microbes affect the changes in the redox of groundwater which is one of the most important properties to estimate the condition of a geological disposal system. It is necessary to quantify microbial biomass on the geological environment as input data in numerical model to evaluate the redox condition. We estimated microbial biomass related to microgeochemical processes in goundwater using real-time PCR. The groundwater was obtained from the Horonobe borehole H17-1-01 (-35m depth) and HDB-10 (-500m depth). The dominant members of microbes at H17-1-01 were Mn(IV)- and Fe(III)-reducers and sulphate reducers. On the other hand, the dominant members of microbes at HDB-10 were sulphate reducers and methanogens. The results of real-time PCR assay showed the same tendency on the results of the cultivation-based methods and 16S-rRNA clone analysis. This result suggests that the real-time PCR will be useful for quantification of microbial biomass on the geological environment.