Taxonomic and Physiological Insights into Novel Bacterial Class Fervidibacteria

• Main Author: Nou, Nancy
• Format: Text
• Language: English
• Published: Digital Scholarship@UNLV 2022
• Subjects: Armatimonadota; Chemoheterotroph; Fervidibacter sacchari; Hyperthermophile; OctSpA1-106; Microbiology; Antarc*; Antarctica
• Online Access: https://digitalscholarship.unlv.edu/thesesdissertations/4607; https://digitalscholarship.unlv.edu/context/thesesdissertations/article/5611/viewcontent/Nou.pdf

Recent studies incorporating cultivation-independent techniques to assess microbial communities, namely metagenomics and single-cell genomics, have pushed the proposed number of bacterial phyla from less than 50 to over 100. One such lineage is the candidate bacterial phylum Fervidibacteria, a strictly thermophilic group that has been identified in terrestrial geothermal springs in North America, Asia, and Antarctica through DNA sequencing. By analyzing 62 medium- and high-quality genomes and through cultivation-dependent experiments, this study serves to set up taxonomy and describe physiology within the taxon. Over the course of this study, we propose Candidatus Fervidibacteria should be reclassified as novel class Fervidibacteria within phylum Armatimonadota. Notably, most members of the Fervidibacteria encode a high number of glycoside hydrolases (GHs), enzymes that depolymerize complex carbohydrates. Taking advantage of this predicted dependence on carbohydrate catabolism, the first pure culture strain of this class, Fervidibacter sacchari PD1T, was enriched for and eventually isolated during this project. To further explore sugar-degrading capabilities, F. sacchari was screened for growth on a variety of polysaccharides and lignocellulosic biomass predicted to be targets for its putative GHs. The substrates allowing for best growth were used as sole carbon sources for differential proteomics experiments in attempt to link enzymes to specific substrates and give a preliminary sense of function for future work. This thesis will provide insights into the biology of this novel bacterial class and expand our knowledge of polysaccharide degradation at high temperatures.