A dual-function Savinase-catalyzed strategy for enhanced bioactive protein hydrolysate production from Nannochloropsis oculata for personal care and cosmetic applications

Microalgae are a sustainable source of bioactive proteins for personal care and cosmetic applications. Conventional alkaline extraction can achieve high protein recovery but relies on harsh chemical conditions that often compromise protein integrity, reduce bioactivity, and raise environmental concerns. Moreover, the extracted proteins often require additional enzymatic hydrolysis to enhance their functionality, thus increasing process complexity. This study proposes a dual-function Savinase-assisted in situ extraction strategy for the simultaneous extraction and functionalization of protein from Nannochloropsis oculata (N. oculata). Process optimization using improvement in protein extraction yield (IPEY) as the performance indicator identified optimal conditions of pH 7, 50 °C, 0.5 wt% Savinase and 2 h hydrolysis, under which a maximum IPEY of 85.1% was achieved. Fluorescence spectroscopy and zeta potential measurements confirmed that Savinase remained structurally stable under the optimized conditions while promoting protein solubilization. The resulting protein hydrolysates exhibited enhanced functional properties, with ABTS•+ radical scavenging activity reaching 83.3% at 5 mg/mL, representing a 56.9% increase compared with the non-enzymatic control. In addition, UV absorption analysis revealed a critical wavelength (λc) of 383.6 nm, indicating broad-spectrum photoprotective potential. Overall, the proposed one-step Savinase-assisted process provides a mild, sustainable, and effective strategy for producing bioactive microalgal protein hydrolysates with strong potential as natural ingredients in skin-protective cosmetic formulations.