酵母脂肪酶酶促合成虾青素琥珀酸酯及优化

研究了酵母脂肪酶在有机溶剂中以琥珀酸酐为酰化试剂酯化合成虾青素琥珀酸酯。液相色谱质谱联用检测表明,酯化产物中既有虾青素单酯也有虾青素二酯。对酶促反应脂肪酶、反应介质、反应底物摩尔比、反应温度等酯化影响因素进行了详细探讨和优化。在所选的几种脂肪酶中,假丝酵母脂肪酶(Candida sp.)的催化活性最好,二甲基亚砜为适宜的反应溶剂,最佳反应温度为45℃。底物摩尔比是决定反应能否进行的关键因素,底物摩尔比为40以上,反应才能进行,摩尔比达到800时,虾青素转化率达到90%以上。底物摩尔比还显著影响产物中单酯和二酯分布,高摩尔比下二酯才能产生。对体系初始含水量和酶量的影响进行了优化。实验结果表明酶法合成虾青素琥珀酸酯具有很好的可行性。

Optimized enzymatic synthesis of astaxanthin succinates in organic solvents

Astaxanthin succinates was synthesized via acylation of astaxanthin with succinic anhydride using Candida sp.lipase as catalyst,the enzymatic product was analyzed by ultra performance liquid chromatography/time-of-flight mass spectrometry(UPLC/Q-TOF-MS)equipped with an electro spray ion source,which indicated that it contains astaxanthin succinic acid monoester and astaxanthin succinic acid diester.The parameters affected the conversion yields of astaxanthin,such as enzyme sources,organic media,reaction temperature and substrates molar ratio in the reaction system,were investigated in detail.The results showed that Candida sp.lipase was the best lipase.The most suitable media for the reaction was DMSO,and the appropriate reaction temperature was 45℃.The molar ratio of succinic anhydride to astaxanthin was the most important parameter which not only determined the conversion yield but also affected the product composition.The enzymatic reaction can occur only when the substrate molar ratio was more than 40,and when it was higher than 150 dieaster can be formed. The influences of water content in the system and amount of lipase was also discussed in the paper,respectively.The experimental results indicate that there is a good possibility of the synthesis of astaxanthin succinates catalyzed by Candida sp.lipase.