Fig. 5From: Efficient heterologous expression of an alkaline lipase and its application in hydrolytic production of free astaxanthinHydrolysis of Ast-E by Lipase-YH, analyzed by HPLC. a Effect of enzyme concentration on free astaxanthin yield. b Effect of buffer (sodium phosphate buffer, pH 7.0) concentration on free astaxanthin yield. c Effect of pH on free astaxanthin yield. d Effect of substrate concentration on free astaxanthin yield. After 1 h culture at pH 7.0, substrate concentration 200 μg/mL, and buffer concentration 0.05 or 0.1 M, enzyme concentration reached 80 U/μg Ast-E, and free astaxanthin yield reached its maximal value (80%)Back to article page