Energy-equivalent cyclic pulsed electric fields enable reversible membrane permeabilization and sustainable protein...

Area of Science:

• Biotechnology
• Microalgal Processing
• Cellular Engineering

Background:

• Microalgal cell walls pose challenges for intracellular protein extraction.
• Pulsed electric field (PEF) technology offers a potential solution for cell disruption.

Purpose of the Study:

• To compare three PEF energy distribution strategies for optimizing protein extraction from Nannochloropsis sp.
• To evaluate the effects of high-voltage few-pulse (HP), low-voltage multi-pulse (LP), and medium-voltage cyclic protocol (MP) on cell permeabilization and protein release.

Main Methods:

• Systematic comparison of HP, LP, and MP PEF protocols at isoenergetic inputs.
• Quantification of membrane permeabilization and protein release.
• Assessment of cellular morphology preservation.

Main Results:

• HP treatment led to rapid but saturating protein release due to irreversible membrane damage.
• LP treatment resulted in minimal cell permeabilization and low protein yield.
• MP protocol achieved controlled permeabilization (51.77%) and sustained protein release without early saturation.
• MP yielded the highest protein concentration (0.259 mg mL⁻¹) at doubled energy input.

Conclusions:

• Cyclic energy redistribution in PEF (MP protocol) balances membrane permeabilization and cell structural integrity.
• The MP strategy is superior to HP and LP for efficient and sustained microalgal protein extraction.