Dokument: Investigation of the Nutrient Storage Pools in Microalgae by Raman Microscopy

Titel:Investigation of the Nutrient Storage Pools in Microalgae by Raman Microscopy
URL für Lesezeichen:
URN (NBN):urn:nbn:de:hbz:061-20211004-112228-9
Dokumententyp:Wissenschaftliche Abschlussarbeiten » Dissertation
Autor: Gao, Lu [Autor]
[Dateien anzeigen]Adobe PDF
[Details]16,05 MB in einer Datei
[ZIP-Datei erzeugen]
Dateien vom 29.09.2021 / geändert 29.09.2021
Beitragende:Prof. Dr. Ebenhöh, Oliver [Betreuer/Doktorvater]
Jun.-Prof. Dr. Axmann, Ilka M. [Betreuer/Doktorvater]
Dewey Dezimal-Klassifikation:500 Naturwissenschaften und Mathematik » 570 Biowissenschaften; Biologie
Beschreibung:Phosphorus, nitrogen, and other nutrients are discharged in waste streams, without being sequestered. The release of these nutrients leads to eutrophication of natural waters and, increases the likelyhood of algal blooms. The capacity of algal cells to accumulate reserves of nutrients can be used to complement conventional wastewater treatment. The resulting algal biomass can then be used to produce biofertilizers and soil conditioners for crop production.
The mechanisms of algal nutrient accumulation are still not adequately understood due to a lack of methods for rapidly identifying and quantifying relevant chemical forms in the compartments of algal cells in situ. Closing the nutrient cycle requires knowledge about the nature and dynamics of these reserve pools in algal cells, which can be obtained by using Raman microscopy. Until recently, the use of this highly potent technique to study nutrient storage pools in algal cells has been rare since the strong fluorescence emission from chlorophyll molecules obscues the Raman scattering signal. Photobleaching is an autofluorescence suppression approach that not only reduces the chlorophyll fluorescence emission but also enhances the signal-to-noise ratios of Raman spectra. This work provides experimental evidence that active photosynthesis and the release of reactive oxygen species in algae facilitates photobleaching with Raman microscopy. Based on this research, using formalin as a chemical fixation reagent for algae is proposed to improve the photobleaching protocol. This finding allows new opportunities for decoupling sampling and the Raman measurements.
The findings on the dynamics of polyphosphate formation and hydrolysis in algal cells analyzed by Raman spectroscopy are presented. Accumulation of polyphosphate occurs during the culture lag phase, within several hours after adding orthophosphate to the phosphorous-starved algae. As growth resumes, the polyphosphate reserves are being consumed. This transient accumulation of large amounts of polyphosphate reserves
presents an opportunity to produce algal biomass with elevated phosphorous contents as biofertilizers or soil conditioners.
Moreover, the presence of guanine crystals is widespread across microalgal species in taxonomically distant phyla and contrasting habitats, including free-living as well as endosymbiotic marine dinoflagellates, which are ecologically relevant. Guanine crystals accumulate after reintroducing nitrogen sources to the starved cells. Then, these intracellular guanine crystals are consumed for growth. This highly dynamic nature suggests that guanine crystals are an important N depot for life in highly dynamic environments. This is particularly important not only for water with fluctuating nutrient availability but also for fragile ecosystems, like coral reefs require low-nutrient environments and are severely threatened by anthropogenic eutrophication. These results may prompt new research that allows a deeper understanding of the mechanisms underlying nitrogen cycling and interactions within the holobiont.
Lizenz:In Copyright
Fachbereich / Einrichtung:Mathematisch- Naturwissenschaftliche Fakultät » WE Biologie
Dokument erstellt am:04.10.2021
Dateien geändert am:04.10.2021
Promotionsantrag am:30.04.2021
Datum der Promotion:10.09.2021
Status: Gast