Developing nanocellulose-based recyclable flocculants for flotation harvesting of microalgae

The European market demand for biomass for feed, food, and fuel production is expected to increase to greater than €25 billion by 2050. Microalgae are an attractive and novel biomass feedstock that requires negligible arable land and resources.

Yet, the small size of microalgae cells (1-10 µm) and low biomass concentration in the liquid culture medium (~1 g/L) complicate the harvesting of microalgal biomass using conventional technologies such as centrifugation or membrane filtration.

It is widely believed that the harvesting of microalgal biomass could be better facilitated by aggregating small individual cells into larger aggregates using chemical flocculants via the flocculation process and then separating the flocculated biomass via gravity sedimentation.

However, challenges remain, including contamination of the microalgal biomass with synthetic chemical flocculants, time-consuming separation, and high water content in the separated biomass.

The combination of reversible bio-based flocculants, and fast separating and concentrated sludge yielding flotation processes can alleviate these challenges, with the added benefit of ensuring low environmental footprint and process costs.

In this project, the experienced researcher (ER) aims to develop a sustainable microalgal harvesting technology that will build on and further improve reversible, low cost, bio-based flocculants derived from cellulose (developed at the host institute) in combination with his expertise on conventional and advanced dissolved air flotation (DAF) processes.

This project will allow the ER to acquire novel scientific skills (synthesis, characterisation of renewable flocculants), which combined with his expertise in DAF, will allow him to create a unique niche in microalgal biotechnology specifically, and water technologies in general.

It will also allow him to bring his management skills to the level required to obtain a tenure-tracked position at a leading European academic institution