The presence of extracellular algal organic matter (AOM) in coagulation, flocculation and flotation processes for harvesting microalgae biomass: problem or opportunity? (R-10593)

Microalgae are an attractive new biomass resource for the production of bio-based chemicals, materials, food or fuels. Microalgae are very small unicellular organisms that grow at low concentrations in waters. Harvesting microalgae from these waters to extract biomass is expensive. Therefore, the current research proposal investigates alternative methods that could make it easier and cheaper to harvest algae. Flocculation group small unicellular microalgae into larger flocs which sink or float, greatly facilitating their separation from the water. One potential drawback for the use of these methods is that algae produce so-called algal organic matter (AOM) which is excreted in the water and alters the floc properties and therefore the separation efficiency. We want to understand how AOM affects the characteristics of the microalgal flocs. We propose to map in detail which (and how much) AOM is produced by different microalgae species at different growth phases, and to evaluate how different concentrations and compositions of AOM affect coagulation and flocculation. If we understand what types of AOM are produced and how they interact with cells and flocs, this will not only help to improve coagulation and flocculation processes, but we may also find useful applications for certain types of AOM. The overarching goal of this research is thus to develop better ways to harvest microalgae, creating new opportunities for green and sustainable biomass production.

Keywords:biomass, flocculation, microalgae

Disciplines:Algae biotechnology