Comparative Genomics of Syntrophic Branched-Chain Fatty Acid Degrading Bacteria

Access this Article

Author(s)

    • Narihiro Takashi
    • Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)|Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign
    • Nobu Masaru K.
    • Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign
    • Tamaki Hideyuki
    • Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)|Biotechnology Research Institute, The University of Tokyo
    • Kamagata Yoichi
    • Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
    • Sekiguchi Yuji
    • Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)
    • Liu Wen-Tso
    • Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign

Abstract

<p>The syntrophic degradation of branched-chain fatty acids (BCFAs) such as 2-methylbutyrate and isobutyrate is an essential step in the production of methane from proteins/amino acids in anaerobic ecosystems. While a few syntrophic BCFA-degrading bacteria have been isolated, their metabolic pathways in BCFA and short-chain fatty acid (SCFA) degradation as well as energy conservation systems remain unclear. In an attempt to identify these pathways, we herein performed comparative genomics of three syntrophic bacteria: 2-methylbutyrate-degrading "<i>Syntrophomonas wolfei</i> subsp. <i>methylbutyratica</i>" strain JCM 14075<sup>T</sup> (=4J5<sup>T</sup>), isobutyrate-degrading <i>Syntrophothermus lipocalidus</i> strain TGB-C1<sup>T</sup>, and non-BCFA-metabolizing <i>S. wolfei</i> subsp. <i>wolfei</i> strain Göttingen<sup>T</sup>. We demonstrated that 4J5 and TGB-C1 both encode multiple genes/gene clusters involved in β-oxidation, as observed in the Göttingen genome, which has multiple copies of genes associated with butyrate degradation. The 4J5 genome possesses phylogenetically distinct β-oxidation genes, which may be involved in 2-methylbutyrate degradation. In addition, these <i>Syntrophomonadaceae</i> strains harbor various hydrogen/formate generation systems (<i>i.e.</i>, electron-bifurcating hydrogenase, formate dehydrogenase, and membrane-bound hydrogenase) and energy-conserving electron transport systems, including electron transfer flavoprotein (ETF)-linked acyl-CoA dehydrogenase, ETF-linked iron-sulfur binding reductase, ETF dehydrogenase (FixABCX), and flavin oxidoreductase-heterodisulfide reductase (Flox-Hdr). Unexpectedly, the TGB-C1 genome encodes a nitrogenase complex, which may function as an alternative H<sub>2</sub> generation mechanism. These results suggest that the BCFA-degrading syntrophic strains 4J5 and TGB-C1 possess specific β-oxidation-related enzymes for BCFA oxidation as well as appropriate energy conservation systems to perform thermodynamically unfavorable syntrophic metabolism.</p>

Journal

  • Microbes and Environments

    Microbes and Environments 31(3), 288-292, 2016

    Japanese Society of Microbial Ecology · The Japanese Society of Soil Microbiology

Codes

  • NII Article ID (NAID)
    130005265098
  • Text Lang
    ENG
  • ISSN
    1342-6311
  • Data Source
    J-STAGE 
Page Top