A review on microalgae cultivation and harvesting, and their biomass extraction processing using ionic liquids

ABSTRACT

The richness of high-value bio-compounds derived from microalgae has made microalgae a promising and sustainable source of useful product. The present work starts with a review on the usage of open pond and photobioreactor in culturing various microalgae strains, followed by an in-depth evaluation on the common harvesting techniques used to collect microalgae from culture medium. The harvesting methods discussed include filtration, centrifugation, flocculation, and flotation. Additionally, the advanced extraction technologies using ionic liquids as extractive solvents applied to extract high-value bio-compounds such as lipids, carbohydrates, proteins, and other bioactive compounds from microalgae biomass are summarized and discussed. However, more work needs to be done to fully utilize the potential of microalgae biomass for the application in large-scale production of biofuels, food additives, and nutritive supplements.

GRAPHICAL ABSTRACT

KEYWORDS:

• Microalgae
• cultivation
• harvesting
• extraction
• ionic liquids
• downstream processing

Highlights

• Microalgae cultivation using open ponds (circular and raceway ponds)

• Different designs of photobioreactors: tubular, vertical column, and flat-plate

• Harvesting techniques: filtration, centrifugation, flocculation, and flotation

• Extraction of bioproducts from microalgae using ionic liquid as extractive solvent

• Bioproducts extracted: lipids, carbohydrates, proteins and bioactive compounds

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors gratefully acknowledge the support of Universiti Tunku Abdul Rahman (UTAR) research grant [Grant number: IPSR/RMC/UTARRF/2019-C1/L05].