@conference{
author = "Santrač, Isidora and Žižić, Milan and AQUILANTI, Giuliana and Gianoncelli, Alessandra and Bonanni, Valentina and Danilović Luković, Jelena and Dimitrijević, Milena and Stanić, Marina and Tanović, Marija and Ćurić, Valentina and Kovačević, Snežana and Spasojević, Ivan",
year = "2023",
abstract = "Haematococcus pluvialis is a unicellular green alga of significant environmental and
economic impact, well adapted to life in extreme conditions such as metal pollution.
Manganese is a common pollutant of water bodies that is related to mining and industrial
drainage, and microalgae have been applied in their bioremediation. To study changes in Mn
redox and coordination form upon interaction with H. pluvialis cells, we exposed late
exponential/early stationary green phase culture to 1 mM MnCl2 (Mn2+) for 72 h. Applied
concentration exceeds microalgal physiological quota but it was non-toxic. Structure of
coordinated Mn in the cells was analyzed using X-ray absorption near edge structure
(XANES) and extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, while
visualization and elemental mapping of Mn was performed by micro X-ray fluorescence
(μXRF). XANES spectra showed that the oxidation form of Mn in H. pluvialis biomass
remained 2+. However, EXAFS showed Mn coordination in microalgae is closer to hydrated
MnSO4 with minor deviation of the local geometry. The shorter Mn-O bonds in biomass,
compared to crystal model, implies somewhat more stable complex in H. pluvialis. This
suggests that H. pluvialis may use sulphated polysaccharides for Mn sequestration, which
would be a newly proposed mechanism of metal coordination and storage. μXRF analysis
showed co-localization of Mn with O and Na, with particularly good superimposition for Mn
and O. O-rich regions may represent vacuoles, filled with organic acids including sulphates,
or starch granules and accumulations of sulphated polysaccharides, which are known to be
produced by H. pluvialis. In addition, vacuoles in plant cells are known to act as sinks for
Na+ ions. These findings are in line with structural analysis that showed dark precipitates in
vacuoles, which are likely accumulations of Mn.",
journal = "International Conference on Biochemical Engineering and Biotechnology for Young Scientists, December 7-8th 2023, Belgrade, Serbia",
title = "The coordination and storage of manganese in the microalga Haematococcus pluvialis",
pages = "45",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_3139"
}
