Integrating bead milling and alkaline solubilization for enhanced protein recovery from microalgae: A comprehensive approach

Microalgae, Chlorella vulgaris exhibits substantial potential as a sustainable food ingredient, but its robust cell wall and limited protein solubility hinder industrial scale protein recovery. A comprehensive solution was devised, integrating dry bead milling and alkaline solubilization. In this method, cells were initially disrupted with bead milling followed by alkali (NaOH) treatment. Without bead milling, protein extraction yield was very low (5.0 % with water, 16.8 % with 0.1 M NaOH) at a biomass loading of 20 g/L. However, the integrated approach significantly improved these results, achieving a maximum protein extraction yield of about 47.3 % at a biomass loading of 100 g/L. The optimized conditions for both dry bead milling (frequency 26 Hz, duration 1.0 h) and alkaline solubilization (biomass weight to NaOH molar ratio 200–250 (g/M), 37 °C, mixing time 1.0 h) played a pivotal role in realizing these improved results. This integrated approach effectively addresses the challenges and holds industrial relevance, offering a more efficient way to extract microalgal protein.