Zhongguo youzhi (Oct 2024)
磁性壳聚糖固定化皱褶假丝酵母脂肪酶 催化酸化油生产脂肪酸Production of fatty acids from acidified oil catalyzed by magnetic chitosan immobilized Candida rugosa lipase
Abstract
为了探索和建立生物催化在油脂副产品利用中的应用策略，将皱褶假丝酵母脂肪酶（CRL）固定在磁性壳聚糖（Fe3O4@CS）载体上制备磁性固定化脂肪酶（Fe3O4@CS-CRL）。采用X射线衍射仪（XRD）、扫描电子显微镜（SEM）和振动样品磁强计（VSM）对Fe3O4@CS-CRL进行了表征，测定了Fe3O4@CS-CRL的脂肪酶负载量、比活性及酶学稳定性,并将其用于催化水解大豆酸化油生产脂肪酸，通过单因素实验研究了催化反应条件对水解率的影响，考察了催化剂的重复使用性。结果表明：制备的Fe3O4@CS-CRL保留了Fe3O4的磁性晶型，呈球形颗粒状，饱和磁化强度为61.1 emu/g，脂肪酶负载量为5.53 mg/g，比活性为7.70 U/g；相比游离CRL，Fe3O4@CS-CRL具有较好的热稳定性、pH稳定性、有机溶剂稳定性及储存稳定性；Fe3O4@CS-CRL催化水解大豆酸化油生产脂肪酸最佳反应条件为反应温度40 ℃、水油比2∶ 1(PBS与大豆酸化油体积比)、催化剂用量15% (以大豆酸化油质量计)、反应时间36 h，在该条件下大豆酸化油的水解率达到84.93%；Fe3O4@CS-CRL经过5次重复使用后保持了61.4%的初始水解活性。综上，Fe3O4@CS-CRL在酸化油中进行催化反应拓宽了固定化CRL的应用范围，该催化反应体系是一种油脂精炼行业副产品的可持续高效利用方式，在代替传统高能耗工业反应中具有良好的前景。To explore and establish strategies for the application of biocatalysis in the utilization of oil by-products, Candida rugosa lipase (CRL) was immobilized on magnetic chitosan (Fe3O4@CS) to prepare magnetic immobilized lipase (Fe3O4@CS-CRL). The Fe3O4 @ CS-CRL was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The lipase loading, specific activity and enzymatic stability of the Fe3O4@CS-CRL were determined. The Fe3O4@CS-CRL was used to catalyze the hydrolysis of acidified soybean oil to produce fatty acids, and the effect of the catalytic reaction conditions on the hydrolysis rate was studied through single factor experiment, and the reuse performance of the catalyst was investigated.The results showed that Fe3O4@CS-CRL retained the magnetic crystal form of Fe3O4, with spherical granule, saturation magnetization strength of 61.1 emu/g, lipase load of 5.53 mg/g, and specific activity of 7.70 U/g. Compared with free CRL, Fe3O4@CS-CRL had better thermal, pH, organic solvent and storage stability, and the optimal reaction conditions for the production of fatty acids from acidified soybean oil catalyzed by Fe3O4@CS-CRL were reaction temperature 40 ℃, water-oil volume ratio 2∶ 1(PBS to acidified soybean oil), enzyme dosage 15% (based on the mass of acidified soybean oil), and reaction time 36 h. Under the optimal conditions, the hydrolysis rate of acidified soybean oil reached 84.93%. In addition, the catalyst Fe3O4@CS-CRL maintained 61.4% of its initial activity after five times of reuse. In conclusion, the Fe3O4@CS-CRL catalytic reaction in acidified oil broadens the application range of immobilized CRL. The catalytic reaction system is a sustainable and efficient use of by-products of oil refining industry, and has a good prospect in replacing the traditional industrial reaction with high energy consumption.
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