Bacterial Diversity in Biological Filtration Plant for the Removal of Iron and Manganese from Groundwater

Abstract

Bacterial diversity of the microbial consortia in a biological filtration plant for the elimination of iron (Fe) and manganese (Mn) from groundwater in Joyo City, Kyoto, Japan, was studied. PCR-based denaturing gradient gel electrophoresis (DGGE) analysis of bacterial 16S ribosomal RNA (rRNA) genes represented at least 15 signals, and nucleotide sequences of the dominant fragments showed similarities to Gallionella and Nitrospira. Phylogenetic analysis using the obtained nucleotide sequences of the 16S rRNA gene clone library showed the presence of the bacteria related to Hyphomicrobium, Gallionella, and Sideroxydans, which are supposed to be involved in Fe and Mn removal. In contrast, no 16S rRNA gene clone affiliated with the genus Leptothrix, which have been regarded as a major Fe-and Mn-oxidizer in biological filtration system, was observed. Though a large number of 16S rRNA gene clones closely related to Nitrospira was obtained, no clone showed high sequence similarity to known ammonium oxidizing bacteria (AOB). However, PCR-amplification of the ammonia monooxigenase gene (amoA) of AOB and ammonia oxidizing archaea (AOA) indicated the presence of both AOB and AOA in this biological filtration plant.

Bacterial Diversity in Biological Filtration System for the Simultaneous Removal of Arsenic, Iron and Manganese from Groundwater

“…The concentration of ammonium-nitrogen was determined by indophenol blue method (Solorzano, 1969). The biological filter media sample from Joyo biological filtration plant was collected as described previously (Thapa Chhetri et al, 2013).…”

“…Total DNA was extracted from 0.05 g (wet weight) of the microbial floc sample using FastDNA SPIN Kit for soil (MP Biochemicals, Solon, OH, USA) as described previously (Thapa Chhetri et al, 2013). Total DNA from Joyo biological filter media sample was also prepared as described (Thapa Chhetri et al, 2013).…”

“…Standard PCR procedure, and PCR procedure for the DGGE analysis with touchdown program, were carried out as described previously (Thapa Chhetri et al, 2013).…”

“…To analyze the molecular diversity of bacterial consortia in the samples, about 190 base pairs (bp) of DNA fragments containing the variable region 3 of bacterial 16S rRNA genes were amplified. Parallel DGGE analysis was carried out using mini-DGGE system NB-1490 (Nihon Eido, Tokyo, Japan) as described previously (Thapa Chhetri et al, 2013). For the analysis, 12.5 μL of PCR products were applied onto 8% (wt/vol) polyacrylamide gel with the denaturing gradients ranging from 30 to 60% denaturant, and electrophoresis was carried out in 1 × TBE buffer at 50 V, 60°C for 4.5 h. The gel was visualized by SYBR Green I staining (Invitrogen, Carlsbad, CA, USA) using fluorescent image analyzer FLA-2000 (Fujifilm, Tokyo, Japan).…”

“…On the other hand, bacterial diversity in the BFR for the simultaneous removal of As, Fe and Mn was not reported yet. Previously, we studied the bacterial diversity in the biological filtration system for the removal of Fe and Mn from groundwater used in the drinking water treatment plant located at Joyo City, Kyoto, Japan, using the PCR-based denaturing gradient gel electrophoresis (DGGE) and clone library analyses of the bacterial 16S rRNA genes (Thapa Chhetri et al, 2013). The results showed the presence of FeOB such as Gallionella and Sideroxydans, and MnOB such as Hyphomicrobium in the BFR, which possibly contribute for the removal of Fe and Mn from groundwater.…”