Table 3 Comparison of advanced microalgal protein extraction techniques alongside conventional methods

Conventional methods

Mechanical disruption (bead milling & homogenization)

• Physically breaks cell walls

• Effective for tough microalgae

• High energy cost

• Heat-induced protein degradation

High

[60, 61]

Chemical extraction (solvent, acid, and alkali)

• Dissolves cell walls using chemicals

• High protein yield

• Harsh chemicals can denature proteins and be environmentally hazardous

Medium

[62, 63]

Sonication

• Uses sound waves to create cavitation

• Effective for small-scale applications

• Can damage proteins with prolonged exposure

Low

[64, 65]

Advanced methods

Enzyme-assisted extraction

• Uses specific enzymes to degrade the cell wall

• Low energy

• High protein purity

• Eco-friendly

• Expensive enzymes

• Species-specific efficiency

Medium-High

[66, 67]

Bead milling with centrifugation

• Mechanical grinding followed by separation

• Scalable

• Effective cell disruption

• High energy consumption

High

[68, 69]

Ultrasound-assisted extraction

• High-frequency ultrasound for cavitation

• Fast

• Efficient

• Minimal solvent use

• Risk of protein degradation

Medium

[70, 71]

Pulsed electric field

• High-voltage pulses create pores in cell walls

• Low energy

• Preserves protein structure

• High initial cost

High

[72, 73]

Supercritical fluid extraction

• Uses supercritical CO₂ and co-solvents

• High purity

• No toxic solvents

• Expensive

• Requires technical expertise

Medium

[74, 75]