修饰固定化青霉素酰化酶在非水相中的催化

为提高酶的催化水解活力和稳定性,将青霉素酰化酶组装于介孔泡沫二氧化硅(MCFs)中,并应用于水/有机混合体系催化水解。分别考察了有机介质种类和体积分数、葡聚糖(Dex10k)修饰对固定化酶活力的影响,研究了不同条件下固定化酶的稳定性。实验结果显示:体积分数20%石油醚中,添加Dex10k的介孔泡沫硅固定化酶比活力达209.5U/mg,是缓冲液中MCFs固定化酶活力的196.2%。20%石油醚中,经25次连续操作,固定化酶保持初始活力的71.5%。结果表明:石油醚等烷烃形成的水/有机体系是适合青霉素酰化酶催化的二相体系,且添加Dex10k能提高固定化酶在二相体系中的催化活力及稳定性。

Catalysis of modified immobilized penicillin acylase in non-aqueous phase

In order to improve the activity and stability of penicillin acylase (PA), PA was co-assembled in mesocellular siliceous foams (MCFs) and used to hydrolyze penicillin in aqueous-organic medium. The effects of kind and volume fraction of organic solvent, addition of Dex 10k on the thermal and operational stability of immobilized enzyme were investigated. In the experiment the specific activity of the modified PA in MCFs was (209.5) U/mg after adding Dex 10k into the petroleum ether with volume fraction 20%. It is 196.2% of unmodified PA in MCFs in full aqueous medium. 71.5% of its initial activity was recovered over 25 repeated batch cycles in the petroleum ether with volume fraction 20%. The results show that the aqueous-petroleum ether two-phase medium is suitable for PA, and co-assembling Dex 10k into immobilized enzyme can enhance the catalytic activity and stability in the two-phase.