UND IRES Research Project
Biosorption Potential of Phototrophic Microorganisms
The comprehensive understanding/description of adsorption mechanisms microalgal biosorption is essential in order to find suitable compounds with either a nutritional value or therapeutic effect that can be adsorbed onto the microalgal cells and their fractions. The study of adsorption of specific organic molecules to microalgal biomass will then enable effective application in environmental biotechnologies.
Molecular mechanisms of algal bioadsorption of organic molecules will be studied for the first time.
Application of algal biomass for adsorption can be widespread, ranging from non-specific wastewater treatment to specific removal of highly toxic effluents and drugs from contaminated ponds.
Biomass surface is rich in uronic acids, glucosamine and proteins, which can interact with dozens of structurally different compounds through hydrogen bonds, p-p* or hydrophobic interactions. Until now, the major part of research efforts has dealt only with the biosorption of small molecules (metals) onto the algal surface. We will focus on adsorption of organic molecules, for which only dyes and several phenolic compounds (xanthohumol, (+)-catechin, (-)-epicatechin, rutin and quercetin) have been documented. Adsorption of specific organic molecules may increase the nutritional and/or therapeutic value of microalgal biomass and enable its broader wider application in environmental biotechnologies. The project focuses on the molecular mechanism of biosorption.
Within this project the adsorption properties of the microalgal biomass, as well as microalgal cell walls and selected components of microalgal cells will be studied. Microalgal species such as Chlorella sp. (green algae, structural and reserve (sulphated)polysaccharides and sporopollenin), Porphyridium sp. (red algae, sulphated structural polysaccharides and exopolysaccharides), Arthrospira sp. (filamentous cyanobacteria, sulphated polysaccharide) etc. will be cultivated as model organisms and used for the extraction of cell walls, which will be further fractionated. The composition and purity of cell walls as well as each fraction will be characterized by FTIR analysis and used for adsorption trials with a broad spectrum of organic, mostly phenolic, compounds. In this case, FTIR analysis will be used for identification of the functional groups of molecules, which are responsible for the adsorbent-adsorbate bonding. To identify the key interactions controlling the biosorption, defined series of compounds with different physicochemical characteristics (hydrophobicity, quality and quantity of functional groups, number of aromatic rings, glycosylation etc.) will be studied during the first year. In the second year, interactions of these compounds with fractions of microalgal biomass (e.g., structural and reserve polysaccharides, sporopollenin) purified to different degree at different environmental conditions (pH, ionic strength) will yield basic knowledge on the molecular sorption mechanism. During the third year, the conclusions to be obtained will be extended by engineering approaches to biosorption aiming at possible future scale-up of processes.