本文選題：磁性微球　切入點(diǎn)：聚乙烯亞胺　出處：《河北大學(xué)》2017年碩士論文

【摘要】：磁性高分子微球具有粒徑小,比表面大,易分離等優(yōu)點(diǎn),在酶的固定化方面有著重要的理論和實(shí)踐意義。本文制備了聚甲基丙烯酸甲酯磁性微球(PMMA)并在其表面接枝修飾聚乙烯亞胺(PEI),研究了磁性微球的蛋白質(zhì)吸附性能及其作為載體對脂肪酶的固定化效果。主要內(nèi)容包括以下幾個部分:第一,以甲基丙烯酸甲酯(MMA)為單體,采用懸浮聚合法制備了PMMA磁性微球,利用掃描電鏡對其進(jìn)行表征,發(fā)現(xiàn)其具有較好的單分散性和球形度,粒徑分布在10-25μm之間。進(jìn)而對微球進(jìn)行酯解,紅外光譜數(shù)據(jù)表明酯解后的微球表面攜帶大量羧基,化學(xué)滴定顯示羧基含量為0.94 mmol/g。第二,利用微球表面的羧基為功能基團(tuán),將不同分子量的聚乙烯亞胺(PEI 600,PEI 1800,PEI 70000)接枝到微球上,并分別使其作為載體吸附模型蛋白BSA,考察了不同分子量PEI接枝微球?qū)Φ鞍踪|(zhì)吸附的影響,并與未接枝PEI的微球吸附性能進(jìn)行了比較。結(jié)果顯示,微球在接枝PEI后能夠顯著提高BSA的吸附量,且接枝PEI 1800的微球吸附量最高,PMMA酯解、PMMA-PEI 600、PMMA-PEI 1800、PMMA-PEI 70000等四種微球的吸附量分別為44 mg/g、54.1 mg/g、62.1 mg/g、47.4 mg/g。實(shí)驗(yàn)進(jìn)一步研究了初始BSA濃度、pH值、離子強(qiáng)度、溫度等因素對BSA吸附的影響。結(jié)果表明,增加離子強(qiáng)度會引起B(yǎng)SA吸附量下降,在pH=7.0,35℃下,磁性微球PMMA-PEI 1800對BSA吸附量達(dá)到最大67 mg/g。此外,吸附-解吸附實(shí)驗(yàn)表明,PMMA-PEI 1800具有良好的重復(fù)使用性。第三,以PMMA-PEI1800磁性微球?yàn)檩d體固定化脂肪酶Candida rugosa lipase(CRL),實(shí)驗(yàn)優(yōu)化了固定化酶的條件,考察了固定化脂肪酶的最適溫度、最適PH及其熱穩(wěn)定性和pH穩(wěn)定性。與游離酶相比,固定化酶的最適溫度、熱穩(wěn)定性、pH穩(wěn)定性均得到了提高,且固定化酶的溫度和PH適應(yīng)范圍比游離酶寬。結(jié)果顯示,pH=7,溫度為35℃,給酶量為4 mg時酶比活最大。
[Abstract]:Magnetic polymer microspheres have the advantages of small particle size, large specific surface, easy separation and so on. It has important theoretical and practical significance in immobilization of enzyme. In this paper, the poly-methyl methacrylate magnetic microspheres (PMMAs) were prepared and grafted onto the surface of polyvinyleneimide (PEI), and the protein adsorption properties of magnetic microspheres were studied. Its immobilization effect on lipase as a carrier. The main contents include the following parts: first, PMMA magnetic microspheres were prepared by suspension polymerization with methyl methacrylate as monomer and characterized by scanning electron microscope. The particle size was between 10 ~ 25 渭 m. Then the microspheres were hydrolyzed by ester. The IR spectra showed that the surface of the microspheres carried a large number of carboxyl groups, and the chemical titration showed that the carboxyl content was 0.94 mmol / g. Secondly, the carboxyl groups on the surface of the microspheres were used as functional groups. Polyethylene imine (PEI) with different molecular weight was grafted onto the microspheres and used as a carrier to adsorb the model protein BSA. The effects of different molecular weight PEI grafted microspheres on protein adsorption were investigated. Compared with the ungrafted PEI microspheres, the results showed that the adsorption capacity of BSA was significantly increased by the grafted PEI microspheres. The adsorption capacity of PMMA-PEI 600 and PMMA-PEI 1800O PMMA-PEI 70000 were 44 mg / g 54.1 mg / g / g ~ 62.1 mg / g ~ (-1) mg / m ~ (4) mg / g respectively. The effects of pH value of initial BSA concentration, ionic strength and temperature on the adsorption of BSA were further studied. The adsorption capacity of BSA decreased with increasing ionic strength. At pH = 7.0 ~ 35 鈩，

本文編號：1697223