Details zur Publikation

Referenztyp Qualifizierungsarbeiten
DOI / URL
Titel (primär) Understanding the role of a novel Magnetospirillum strain as an anaerobic toluene degrader in constructed wetland model systems through integrated omics
Autor Meyer-Cifuentes, I.;
Erscheinungsjahr 2018
Department UBT;
Sprache englisch;
POF III (gesamt) T41;
Abstract In past studies the degradation of toluene was analyzed in planted fixed-bed reactors (PFRs) supplied with 0.5 mM of toluene. Mainly aerobic bacteria within the Burkholderiales seemed to degrade toluene in the PFRs, although metagenomic analysis later revealed a significant amount of anaerobic toluene degrading bacteria, mainly identified as Magnetospirillum spp. In addition, bssA, the gene encoding for benzylsuccinate synthase, as the initial enzyme for anaerobic toluene degradation, was the highest gene expressed (among others), however its correspondent peptide was not detected. Based on these findings the main goal of this thesis was to isolate anaerobic-toluene degraders from these PFRs. This led to the isolation of spirilli-shaped bacteria, designated later as Magnetospirillum sp. 15-1. Strain 15-1 grew well with up to 0.5 mM of toluene with nitrate as the electron acceptor and a wide range of organic acids under aerobic and denitrifying conditions. Succinate grown 15-1 cells adapted to the presence of toxic concentrations of toluene by increasing the amount of saturated fatty acids on their membrane. Further, the regulation of bssA was investigated at the gene and protein level in the presence of toluene, oxygen and different nitrate concentrations. The bssA gene and protein were induced by toluene and regulated in the presence of high nitrate concentrations. Under oxic conditions only the bssA gene was expressed if toluene was present while its corresponding peptides were apparently not synthesized. Therefore, the findings of this research demonstrated that strain 15-1 might survive in systems contaminated with toluene by degrading it and changing their membrane conformation. Although expression of bssA is induced under anoxic conditions in the presence of toluene, the level of its expression can be additionally controlled by growth-inhibiting nitrate concentrations. Gene expression to protein synthesis seems to be more complex if the oxygen condition changes in the environment. In this way, post-transcriptional regulation might play an important role in the regulation of the enzymatic synthesis needed for toluene degradation.
ID 20921
dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=20921
Meyer-Cifuentes, I. (2018):
Understanding the role of a novel Magnetospirillum strain as an anaerobic toluene degrader in constructed wetland model systems through integrated omics
Dissertation, Universität Leipzig
135 pp.