Lipid extraction and biomass processing

The recovery of proteins, lipids and polysaccharides from microalgal biomass must be highly efficient in terms of capital investment and energy consumption. The development of effective processes requires a high level understanding of the underlying biology, chemical engineering principles, and process economics.

The APG develops scalable and energy efficient means of fractionating algae biomass into pure components that can be used as food ingredients or for the production of chemicals and fuels.

This includes a low solvent, low temperature process for extracting lipids from wet microalgae biomass (Olmstead et al. 2013). By avoiding energy-intensive drying, and by enabling lipid extraction to be performed with minimal solvent this process can be highly energy efficient (Martin 2016). The process involves Concentration, Incubation, Disruption, Extraction and Separation (CIDES) and can be used to fractionate and retain the value of the lipids (including omega-3 fatty acids) and protein (Halim et al. 2016). Subsequent investigations by Dr Halim have revealed the mechanisms behind the cell weakening that occurs during the incubation stage of the CIDES process (Halim et al. 2019).

More recently, we have utilised ultrasonic waves to selectively recover extracellular polysaccharides from diatom algae (Yatipanthalawa et al. 2022). In addition to producing polysaccharides with potential as food ingredients, this method enhances the rheological properties and lipid recovery of the remaining biomass.

References

Yatipanthalawa, B.S., Ashokkumar, M., Scales, P.J., Martin, G.J.O. (2022). Ultrasound-Assisted Extracellular Polymeric Substance Removal from the Diatom Navicula sp.: A Route to Functional Polysaccharides and More Efficient Algal Biorefineries. ACS Sustainable Chemistry & Engineering, 10(5), 1795-1804.

Halim, R., Hill, D.R.A., Hanssen, E., Webley, P.A., Blackburn, S., Grossman, A.R., Posten, C., Martin, G.J.O. (2019). Towards sustainable microalgal biomass processing: anaerobic induction of autolytic cell-wall self-ingestion in lipid-rich Nannochloropsis slurries. Green Chemistry, 21, 2967-2982.

G.J.O. Martin, Energy requirements for wet solvent extraction of lipids from microalgal biomass (2016). Bioresource Technology, 205  40–47.

R. Halim, P.A. Webley, G.J.O. Martin (2016). The CIDES Process: fractionation of concentrated microalgal paste for co-production of biofuel, nutraceuticals, and high-grade protein feed, Algal Research, 19  299–306.

I.L.D. Olmstead, S.E. Kentish, P.J. Scales, G.J.O. Martin (2013). Low solvent, low temperature method for extracting biodiesel lipids from concentrated microalgal biomass, Bioresource Technology, 148  615–619.