Syntrophic saturated fatty acid-oxidizing bacteria and their phylogeny: An extremely thermophilic, methanogenic bacterium and its plasmid

Enriched from rural anaerobic digester sludge, anaerobic, sporing and nonsporing, curved and straight rod-shaped bacteria were isolated as cocultures with H$\sb2$- and formate-utilizing Methanospirillum hungatei or Desulfovibrio strain G-11. They oxidized four carbon to eight carbon saturated fatty acids, including isobutyrate and 2-methylbutyrate, with H$\sb2$ or formate as the electron sink product. The cocultures were adapted to grow on unsaturated acid crotonate, and pure subcultures of the syntrophs were then isolated. The crotonate-grown pure cultures alone did not grow on butyrate in either the presence or absence of some common electron acceptors. However, when they were reconstituted with M. hungatei, growth on butyrate again occurred. The pure isolates were subjected to 16S rRNA sequence analysis. Several previously documented mesophilic fatty acid-β-oxidizing syntrophs were also subjected to this comparative sequence analysis after adaptation to grow on crotonate and further purification. The sequence analyses revealed that our new sporeforming and nonsporing isolates and other syntrophs we sequenced, with either Gram-negative or Gram-positive cell wall ultrastructure, all belonged to the phylogenetically Gram-positive phylum of eubacteria. However, they were not closely related to any of the clusters of the Gram-positive phylum with which they were compared but they were all closely related to each other, forming a new cluster in the phylum. We recommended that this cluster be placed in the new family SYTROPHOMONADACEAE.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Microbiology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Zhao, Hongxue

Contributors dc:contributor

• Bryant, Marvin P.

• Biology, Microbiology

Statement dc:rights

• Copyright 1991 Zhao, Hongxue

Language dc:language

eng

Identifier

AAI9136780
(UMI)AAI9136780

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F19250