纳米复合材料
脂肪酶
皮克林乳液
复合数
接触角
材料科学
矿化(土壤科学)
化学
南极洲假丝酵母
结晶度
化学工程
乳状液
Zeta电位
有机化学
催化作用
纳米技术
纳米颗粒
酶
复合材料
工程类
氮气
作者
Qingcheng Liang,Zhigang Luo,Xuanxuan Lu
出处
期刊:ACS Sustainable Chemistry & Engineering
[American Chemical Society]
日期:2019-03-03
卷期号:7 (7): 7127-7139
被引量:67
标识
DOI:10.1021/acssuschemeng.9b00113
摘要
In this study, a brand new biocatalytic system was successfully accomplished by combination of metal–organic frameworks (MOFs) biomimetic mineralization and Pickering interfacial system for enhanced lipase catalysis and recycling in organic media. Specifically, a highly porous lipase-loaded MOF composite was synthesized via biomimetic mineralization of ZIF-8 around lipase from Candida rugosa (CRL). With increasing enzyme loading amount, the role of CRL in modulating size, crystallinity, and interior or exterior structure of the composite was meticulously clarified. In this process, we disclosed a gradation from the crystal into an amorphous form for CRL-loaded ZIF-8 and more importantly discovered an enrichment of enzymes on the surface of the crystals. Combining this phenomenon with results of dynamic light scattering, zeta potential, and water contact angle, as well as styrene-induced interface solidification, we confirmed the surface-embedded CRL of the crystal played a role in adjusting the surface chemical characteristics of the composite that directly affected the stability of the emulsion and the distribution rule of stabilizers on the oil–water interface. Furthermore, through the comparison of hydrolyses involving a small substrate (p-nitrophenyl butyrate) and a larger one (p-nitrophenyl palmitate), a stable oil-in-water Pickering emulsion with an optimized quantity and integrity of oil droplets was proved to achieve the highest catalytic efficiency. Notably, because size selectivity of the ZIF-8 shell induced different locations of the substrates in contact with the enzymes, an obvious discrepancy in catalysis efficiency was observed for substrates with different sizes. Impressively, we could employ this system for transesterification by changing only the encapsulated enzyme (lipase B from Candida antarctica expressed in Aspergillus) and optimizing the oil/water ratio. The excellent catalytic performance highlighted the versatility of this interfacial biocatalytic system.
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