In this study, sequential strategy based design was applied to optimize the microalgae. Pavlova lutheri mass culture conditions and fermentation conditions of the cultured algae by proteolytic yeast Candidia rugopelliculosa to obtain small peptide chains. This optimization of culture and fermentation conditions by response surface methodology (RSM) finally leads to effective purification of a bioactive peptide MPGPLSPL (793.01 Da) with hydroxyl radical scavenging activity. Collectively, these results indicated that microalgae P. lutheri can enhance the hydroxyl radical inhibiting effect through protein hydrolysis process under RSM optimal condition. (C) 2011 Elsevier Ltd. All rights reserved.