Astaxanthin Preparation by Lipase‐Catalyzed Hydrolysis of Its Esters from  Haematococcus pluvialis  Algal Extracts

Abstract:  Five of 8 fungal lipases screened were found to effectively hydrolyze astaxanthin esters from  Haematococcus pluvialis  algal cell extracts. Among these, an alkaline lipase from  Penicillium cyclopium , expressed in  Pichia pastoris , had the highest enzymolysis efficiency. Tween80 was shown to be an effective emulsifier in this lipase hydrolysis system for the 1st time. A series of experiments were performed to find optimal conditions for hydrolysis (pH, temperature, reaction time, lipase dosage). In the optimal reaction system, Tween80 and  H. pluvialis  extracts (mass ratio 1:1) were emulsified and added to the above lipase at a dosage of 4.6 U/μg (relative to total carotenoids), in phosphate buffer (0.1 M, pH 7.0), and incubated at 28 °C for 7 h, with agitation at 180 rpm. The free astaxanthin recovery ratio under these conditions was 63.2%. Practical Application:  The chemical hydrolysis of astaxanthin esters from both  H. pluvialis  and  Adonis  rarely produced astaxanthin but always astacene and was therefore not considered applicable for industrial use. We would expect that our effort in this study was able to make a contribution to construct a new procedure apart from chemical methods.