The role of algal organic matter in microalgae biomass harvesting: a multi-scale study (R-12559)

Microalgae are an attractive new biomass resource for the production of bio-based chemicals, materials, food or fuels. Microalgae are small unicellular microorganisms that grow at low concentrations in waters. Harvesting microalgae from these waters to extract biomass is expensive. Flocculation method consists in aggregating small unicellular microalgae into larger flocs which sink or float, greatly facilitating their separation from the water. One potential drawback for the use of this method is that microalgae produce so-called algal organic matter (AOM) which is excreted in the water and alters the floc properties and therefore the separation efficiency. The goal of this project is to understand how AOM affects the characteristics of microalgae flocs produced using different coagulants, by focusing on the study of the interactions between algae cells, flocs and extracellular organic matter using Atomic Force Microscopy. We propose to map in detail which fraction of AOM is interacting in an inhibitory or promoting way in flocculation and flotation processes by different microalgae species at different growth phases. If we understand what types of AOM are produced and how they interact with cells and flocs, this will not only help to improve flocculation processes, but we may also find useful applications for certain types of AOM. The overarching aim of this research is thus to develop better ways to harvest microalgae, creating new opportunities for green and sustainable biomass production.

Keywords:atomic force microscopy, coagulation, Flotation

Disciplines:Algae biotechnology