Cell-wall disruption and lipid/astaxanthin extraction from microalgae: Chlorella and Haematococcus

Area of Science:

• Biotechnology
• Phycology
• Biorefining

Background:

• Microalgae are increasingly important sources for biofuels and nutraceuticals.
• Efficient recovery of intracellular products like lipids and astaxanthin is hindered by rigid microalgal cell walls.
• Chlorella and Haematococcus are key microalgal species for commercial product development.

Purpose of the Study:

• To review and analyze recent advancements in microalgal cell-wall disruption and extraction methods.
• To focus on lipid extraction from Chlorella and astaxanthin extraction from Haematococcus.
• To provide a comparative guide for implementing practical downstream processing in microalgal biorefineries.

Main Methods:

• Analysis of microalgal cell-wall composition and structure.
• Detailed discussion and comparison of chemical, physical, physico-chemical, and biological cell-wall breakage methods.
• Evaluation of extraction techniques based on efficiency, energy use, solvent requirements, biomass conditions, toxicity, and scalability.

Main Results:

• Identified cell-wall characteristics as a critical bottleneck for intracellular component recovery.
• Compared various cell-disruption and extraction methods for lipid and astaxanthin recovery.
• Highlighted factors influencing method selection, including efficiency, cost, and environmental impact.

Conclusions:

• Effective cell-wall disruption is crucial for optimizing lipid and astaxanthin yields from microalgae.
• Method selection depends on specific product targets, microalgal species, and economic viability.
• This review offers guidance for developing efficient downstream processing strategies for microalgal biorefineries.