介孔TiO_2晶须材料的硅烷化改性及其对载体pzc值和酶负载性能的影响  

Effect of surface modification with silane coupling agent on enhancing pzc value and enzyme loading capacity of mesoporous TiO_2 whiskers

作　　者：叶丽静[1] 房鑫[1] 王浩绮[1] 姚忠[1] 熊强[1] 周治[1] 孙芸[1] 韦萍[1] 

机构地区：[1]南京工业大学食品与轻工学院,江苏南京210009

出　　处：《化工学报》2013年第6期2160-2168,共9页CIESC Journal

基　　金：江苏省高校自然科学研究重大基金项目(10KJA530014);江苏省科技支撑计划(社会发展)基金项目(SBE 201078182);江苏省自然科学基金项目(BK2011799;BK2012825)

摘　　要：以3-氨丙基三乙氧基硅烷(APTES)对介孔二氧化钛晶须(MTiO2_ws)进行表面修饰,使其电荷零点值(pzc)由5.3提高至6.8,改性后材料MTiO2_ws-APTES的比表面积略有上升,但孔结构基本不变。以MTiO2_ws-APTES为载体对γ-谷氨酰转肽酶(GGT)进行了固定化,当给酶量小于150U.g-1时,酶活回收率均大于99%,固定化酶MTiO2_ws-APTES-GGT的比活力最高可达184.0U.g-1,对酶的负载性能显著优于MTiO2_ws。相比于游离酶,MTiO2_ws-APTES-GGT的最适温度和热稳定性均略有下降,但pH稳定性明显优于游离酶和以MTiO2_ws为载体的固定化酶(MTiO2_ws-GGT);MTiO2_ws-APTES-GGT对γ-谷氨酰对硝基苯胺(GpNA)的亲和力常数(Km)为0.889mmol·L-1,较游离酶有所上升,但小于MTiO2_ws-GGT。MTiO2_ws-APTES-GGT的稳定性良好,经4℃下储藏60d,连续使用21批次后残余酶活仍可达初始值的80.07%。Mesoporous TiO2 whiskers （MTiO2 _ ws）were chemically modified with 3-aminopropyltriethyloxy silane （APTES）. As a result, the point of zero charge （pzc） for the modified material （MTiO2 _ ws- APTES） rose from 5.3 to 6.8. Also the specific surface area of MTiO2 _ ws-APTES slightly increased, but the pore structure had little change compared to that of MTiO2 _ ws. Then, MTiO2 _ ws-APTES was used as the support for γ-glutamyltranspeptidase （GGT） immobilization. MTiO2 _ ws-APTES showed better loading capacity than MTiO2 _ ws. While the enzyme concentration was less than 150 U . g- 1, the recovery of activity was above 99% and the highest specific activity for immobilized GGT （MTiO2 _ ws APTES-GGT） was 184.0 U . g -1. Although both optimal temperature and thermal stability of MTiO2 _ws-APTES-GGT slightly decreased compared with the native enzyme, pH stability was greatly improved. The affinity constant （Kin） of MTiO2 _ ws-APTES-GGT toward γ-glutamyl-p-nitroaniline （GpNA） was also determined to be 0. 889 mmol . L -1, which was higher than that of the native enzyme, but less than that of MTiO2 _ ws-GGT. After storage at 4℃ for 60 days and reused for 21 batches, MTiO2 _ ws-APTES-GGT maintained 80.07% of its initial activity.

关 键 词：介孔氧化钛晶须 化学改性 3-氨丙基三乙氧基硅烷 固定化酶 稳定性 担载量 

分 类 号：Q814[生物学—生物工程]