Comparative analysis of sulfur oxidation pathways in haloalkaliphilic thiocyanate-utilizing species of the genus Thioalkalivibrio

The results presented in this thesis represent an advancement of our knowledge of the oxidation of reduced sulfur compounds by Thioalkalivibrio, a unique group of haloalkaliphilic chemolithoautotrophic Gammaproteobacteria isolated from soda lakes. We have demonstrated—using a combination of comparative genomics and transcriptomics—that a cluster of genes conserved in ten thiocyanate-utilizing strains is indeed involved in thiocyanate metabolism in vivo. Additionally, we have presented a comprehensive analysis of the distribution and diversity of sulfur genes in the genomes of 75 Thioalkalivibrio strains, highlighting a possible common pathway for sulfur oxidation while reaffirming the complex phylogenetic relation of Thioalkalivibrio with other SOB. Finally, this research provides a number of avenues for future research, such as the function of poorly-annotated genes in the thiocyanate dehydrogenase cluster and the apparent redundancy of sulfite-oxidizing enzyme systems.