African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 4957

Full Length Research Paper

Isolation and identification of bacteria from high-temperature compost at temperatures exceeding 90°C

Kikue Hirota
  • Kikue Hirota
  • Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517, Japan.
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Chihaya Miura
  • Chihaya Miura
  • Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517, Japan.
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Nobuhito Motomura
  • Nobuhito Motomura
  • Chitose Recycling Factory, Chuuou Chitose 066-0007, Japan.
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Hidetoshi Matsuyama
  • Hidetoshi Matsuyama
  • Department of Bioscience and Technology, School of Biological Science and Engineering, Tokai University, Minamisawa, Minami-ku, Sapporo 005-8601, Japan.
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Isao Yumoto
  • Isao Yumoto
  • Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517, Japan.
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  •  Received: 21 November 2018
  •  Accepted: 15 January 2019
  •  Published: 21 February 2019

Abstract

Conventional composts exhibit temperatures ranging from 50 to 80°C during organic waste degradation by microorganisms. In high-temperature compost, temperatures can reach ≥90°C with appropriate bottom aeration. To elucidate specific characteristics of the bacterial activity in high-temperature compost and to regenerate a high-temperature compost from isolates, bacterial isolation and characterization were performed. Although the isolated taxa varied depending on sample and temperature, the use of gellan gum medium and cultivation at 60°C led to high diversity among the isolated taxa. In addition, combining the use of the compost extract with water-solvent medium led to the isolation of more diverse species. Based on 16S rRNA gene sequencing, the isolates shared ≥99% similarity with Geobacillus thermodenitrificans, Ureibacillus spp. (Ureibacillus suwonensis, Ureibacillus themosphaericus) and Aeribacillus pallidus, and these isolates were isolated from both steady-state and newly prepared small-scale composts. Thus, these taxa were considered to be frequently observed regardless of the composting process. Although the frequency of isolation of mesophilic bacteria from this high-temperature compost was lower than that from ordinary composts, these bacteria have been isolated from ordinary composts and there was a discrepancy between the in situ compost temperature (≥90°C) and their maximum growth temperature (≤70°C).
 
Key words: High-temperature compost, Geobacillus thermodenitrificans, Ureibacillus suwonensis, Ureibacillus thermosphaericus, Aeribacillus pallidus.