Alternative Title水中のヒ素、鉄およびマンガンの生物学的除去に関与する細菌群集構造の分子生物学的手法を用いた解析
Note (General)Biological filtration plant is a simple, cost-effective and eco-friend system toremove soluble iron (Fe) and manganese (Mn) ions from groundwater. In thissystem, the combined biological activities along with chemical reactions arecarried out by naturally occurring Fe- and Mn-oxidizing microorganisms.These microorganisms oxidize Fe and Mn to produce biogenic Fe and Mnoxides, which they are reactive to remove the soluble toxic metal ions likearsenic (As), cadmium (Cd), lead (Pb) from the groundwater. However, manybiological filtration plants have been designed and developed for thedrinking water purification in all over the world. In Japan, single stage rapidfiltration plants have been operated to purify the drinking water byremoving Fe and Mn from the raw groundwater. The biological filtrationplant has been established to treat Fe and Mn at Joyo City, Kyoto Prefecture,Japan. But the biological removal method for toxic heavy metal for As is stillunder testing in the world. Similarly, the biological filtration pilot plant wasoperated at Muko City, Kyoto Prefecture to study the simultaneous biologicalremoval of As, Fe and Mn from the raw groundwater. In these biologicalfiltration plants, >70% of metal ions were removed without using anychemical reagents. The complete biological structures in these systems werenot reported yet except few microscopic analyses. Therefore, the biologicalstructures in these plants were studied via polymerase chain reaction (PCR)based culture-independent molecular biological techniques using 16Sribosomal RNA gene (16S rDNA).Bacterial diversities in those plants were studied by denaturing gradient gelelectrophoresis (DGGE), restriction fragment length polymorphism (RFLP),clone library analysis, real-time PCR. In Joyo plant, Sideroxydans andHyphomicrobium related bacterial consortia were respectively detected asthe dominant Fe-oxidizing bacteria (FeOB) and Mn-oxidizing bacteria(MnOB) via clone library analysis. These results showed that Gallionella andLeptothrix are not always the dominant bacteria in Fe and Mn removalbiological plants to oxidize soluble Fe and Mn. However, Gallionella andLeptothrix related common iron bacteria were studied as the dominantFeOB and MnOB in As removal biological filtration plant by the same clonelibrary analysis. The quantitative real-time PCR analysis estimated >10% ofLeptothrix related 16S rRNA gene harboring PSP-6 sequences in both plants.The genes encoding ammonia monooxygenase subunit A (amoA) of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) wereamplified that present in the DNA solution extracted from biological filtermedia (BFM) of Joyo plant, but only the AOB-amoA was amplified inextracted DNA solution from the microbial flocs of the pilot plant. But theaoxB gene encoding arsenite oxidase was not amplified in the DNA solutionof the pilot plant. Therefore, it was considered in biological pilot plant thatAs-oxidizing bacteria (AsOB) were not prominent to remove As(III/V) ions,alternatively biogenic Fe and Mn oxides produced by FeOB and MnOB couldremove soluble As(III/V).To study the biological removal mechanism for these heavy metals,Mn-oxidizing microbial consortia were cultivated in modified PYM (mPYM)(Peptone: 1 g/l, Yeast-extract: 0.1 g/l and manganese: 30 mg/l of final Mn(II))(Vandenabeele et al., 1995) culture media to produce massive Mn oxidesusing the BFM of Joyo. In the cultured microbial consortia in mPYM, Mnoxides were produced and Leptothrix and Hyphomicrobium related MnOBwere studied via PCR-DGGE analysis. Those reactive microbial consortiawere applied for the simultaneous removal of Mn(II) and As(III/V).Ultimately, adequate As ions (>97% of As (III) and >75% of As(V) of initialconcentration of 500 ?g/l) were removed by those cultivated Mn-oxidizingmicrobial consortia (2-mL) in mPYM after three weeks incubation. MnOBsuch as Leptothrix and Hyphomicrobium related 16S rRNA gene copies wereestimated in the cultured mPYM by real-time PCR. Naturally occurringAsOB in the BFM of Joyo plant became active after cultivation to remove Asin mPYM. Bosea, Agrobacterium, Sinorhizobium related bacteria wereisolated from the clone library analysis for BFM of Joyo plant and two weekscultured microbial consortia. These Mn-oxidizing microbial consortia wouldbe more applicable in new welcome plants for As removal, however its detailsis required to be studied.
Collection (particular)国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文
Date Accepted (W3CDTF)2016-08-04T09:59:51+09:00
Data Provider (Database)国立国会図書館 : 国立国会図書館デジタルコレクション