Anti-bacterial Effects of MnO2 on the Enrichment of Manganese-oxidizing Bacteria in Downflow Hanging Sponge Reactors

Shuji Matsushita; Takafumi Hiroe; Hiromi Kambara; Ahmad Shoiful; Yoshiteru Aoi; Tomonori Kindaichi; Noriatsu Ozaki; Hiroyuki Imachi; Akiyoshi Ohashi

doi:10.1264/jsme2.ME20052

Regular Paper

Anti-bacterial Effects of MnO₂ on the Enrichment of Manganese-oxidizing Bacteria in Downflow Hanging Sponge Reactors

Shuji Matsushita, Takafumi Hiroe, Hiromi Kambara, Ahmad Shoiful, Yoshiteru Aoi, Tomonori Kindaichi, Noriatsu Ozaki, Hiroyuki Imachi, Akiyoshi Ohashi

Author information

Shuji Matsushita
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University
Western Region Industrial Research Center, Hiroshima Prefectural Technology Research Institute
Takafumi Hiroe
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University
Hiromi Kambara
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University
Ahmad Shoiful
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University
Center of Technology for the Environment, Agency for the Assessment and Application of Technology
Yoshiteru Aoi
Environmental Microbiology Laboratory, Graduate School of Advance Sciences of Matter, Hiroshima University
Tomonori Kindaichi
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University
Noriatsu Ozaki
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University
Hiroyuki Imachi
Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science & Technology
Akiyoshi Ohashi
Department of Civil and Environmental Engineering, Graduate School of Advanced Science and Engineering, Hiroshima University

Keywords: anti-bacterial effects, biological manganese oxidation, biological manganese oxide, downflow hanging sponge reactor, metal oxide

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Supplementary material

2020 Volume 35 Issue 4 Article ID: ME20052

DOI https://doi.org/10.1264/jsme2.ME20052

Details

Abstract

We focused on the use of abiotic MnO₂ to develop reactors for enriching manganese-oxidizing bacteria (MnOB), which may then be used to treat harmful heavy metal-containing wastewater and in the recovery of useful minor metals. Downflow hanging sponge (DHS) reactors were used under aerobic and open conditions to investigate the potential for MnOB enrichment. The results of an experiment that required a continuous supply of organic feed solution containing Mn(II) demonstrated that MnOB enrichment and Mn(II) removal were unsuccessful in the DHS reactor when plain sponge cubes were used. However, MnOB enrichment was successful within a very short operational period when sponge cubes initially containing abiotic MnO₂ were installed. The results of a microbial community analysis and MnOB isolation revealed that MnOB belonging to Comamonadaceae or Pseudomonas played a major role in Mn(II) oxidation. Successful MnOB enrichment was attributed to several unidentified species of Chitinophagaceae and Gemmataceae, which were estimated to be intolerant of MnO₂, being unable to grow on sponge cubes containing MnO₂. The present results show that MnO₂ exerted anti-bacterial effects and inhibited the growth of certain non-MnOB groups that were intolerant of MnO₂, thereby enabling enriched MnOB to competitively consume more substrate than MnO₂-intolerant bacteria.

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