Project description:Chemolithoautotrophic sulfur-oxidizing bacteria (SOB) are crucial key players in biotechnological processes to remove hydrogen sulfide from sour gas streams. Several different haloalkaliphilic SOB have been detected and isolated from lab- and full-scale facilities, which all performed differently considering end product yields (sulfur and sulfate) and conversion rates. Understanding and regulating bacterial community dynamics in biodesulfurization processes will enable optimization of the process operation. We developed quantitative PCR (qPCR) assays to quantify haloalkaliphilic sulfur-oxidizing gammaproteobacterial species Alkalilimnicola ehrlichii, Thioalkalivibrio sulfidiphilus, and Thioalkalibacter halophilus that dominate bacterial communities of biodesulfurization lab- and full-scale installations at haloalkaline conditions. The specificity and PCR efficiency of novel primer sets were evaluated using pure cultures of these target species. We further validated the qPCR assays by quantification of target organisms in five globally distributed full-scale biodesulfurization installations. The qPCR assays perform a sensitive and accurate quantification of Alkalilimnicola ehrlichii, Thioalkalivibrio sulfidiphilus and Thioalkalibacter halophilus, thus providing rapid and valuable insights into process performance and SOB growth dynamics in gas biodesulfurization systems.
Project description:Study of the photosynthetic metabolism of purple sulphur bacteria Halorhodospira halophila by analysing the proteome of the bacteria cultivated with various sulphur compounds. In this way for the first time a comprehensive sulphur-oxidative photosynthetic network of an Halorhodospiraceaen is presented. As some Ectothiorhodospiraceae have been shown to use arsenite as photosynthetic electron donor, We performed a mass spectrometry-based whole proteome analysis with label-free quantification of H. halophila photoheterotrophically grown in the presence of various inorganic reduced sulphur compounds and in the concomitant presence of sulphide and arsenite, in order to identify proteins (enzymes and electron carriers) involved in its photosynthetic metabolism. Quantitative proteomics revealed that the SoxAXYZB system, typically dedicated to thiosulphate oxidation, is overproduced in this latter growth condition as are two electron carriers, the cytochrome c551/c5 and PioC/HiPIP III. Taken together, these results argue in favour of a chemically-formed thioarsenate oxidized by the Sox system, with c551/c5 and PioC/HiPIP III funnelling electrons towards the Reaction Centre.
Project description:Bacteria use different strategies to sense and respond to reduced sulfur compounds such as sulfide or thiosulfate. In the methylotrophic Alphaproteobacterium Hyphomicrobium denitrificans, which uses thiosulfate as an accessory electron donor, this involves two distinct but related ArsR-type transcriptional repressors, sHdrR and SoxR. Here, we focused on identifying target genes regulated by these repressors. This was achieved by generating individual deletions of each regulator gene, and performing comparative RNA-seq analysis.
Project description:This SuperSeries is composed of the following subset Series: GSE8015: Pyruvate fermentation vs Lactate-Sulfate GSE8037: Hydrogen vs Lactate as electron donor in Sulfate reduction GSE8071: Pyruvate vs Lactate as electron donor in Sulfate reduction GSE8072: Thiosulfate vs Sulfate as electron acceptor in Sulfate reduction Keywords: SuperSeries Refer to individual Series
