No abstract

The first sorbent with high CO2 selectivity and poor water affinity addresses need for trace CO2 remediation in confined spaces.

The use of a metal–organic framework (MOF) as a support for the in situ immobilization of enzymes was explored. The MOF support, a Basolite F300‐like material, was prepared from FeCl3 and the tridentate linker trimesic acid. Immobilization of alcohol dehydrogenase, lipase, and glucose oxidase was performed in situ under mild conditions (aqueous solution, neutral pH, and at room temperature) in a rapid and facile manner with retention of activity for at least 1 week. The catalytic activities of lipase and glucose oxidase were similar to the activities of the free enzymes; with alcohol dehydrogenase, there was a substantial decrease in activity on immobilization that may arise from diffusion limitations. The approach demonstrates that a MOF material, prepared from cheap and commercially available materials, can be successively utilized to prepare stable and catalytically active biocatalysts in a rapid and facile manner.

BACKGROUND: Very recently, metal-organic framework (MOF) materials have been postulated as emerging supports to achieve solid-state enzyme-contained biocatalysts. In this work, post-synthesis and in situ strategies to immobilize -glucosidase and laccase on different MOF materials were studied. The MOF-based supports, i.e. MIL-53(Al), NH 2 -MIL-53(Al) and Mg-MOF-74, were prepared under soft and sustainable conditions (room temperature and pH values compatible with enzymatic activity), allowing development of the in situ strategy. RESULTS:In both post-synthesis and in situ approaches, the intercrystalline mesoporosity of the MOF-based support favored the immobilization efficiency or the specific activity. The latter expressed as units per milligram of immobilized enzyme was higher in the post-synthesis immobilization, whereas the biocatalysts prepared in situ gave much higher enzyme loading (over 85%) and lower enzyme leaching (around 5%). The in situ approach even worked in a non-aqueous (N,N-dimethylformamide) media in which the free enzyme was completely inactive. The immobilized enzymes are much larger than the structural pores of the MOFs. CONCLUSIONS: Enzymes can be efficiently immobilized on nanocrystalline MOFs prepared under soft and sustainable conditions despite the supports lacking large enough pores to host the enzymes. The in situ approach is very efficient capturing enzymes and preserving some of their activity even under adverse conditions. Electrophoresis test of enzyme retention in biocatalystsThe efficiency of the enzyme encapsulation was studied by means of SDS-PAGE electrophoresis. Since the solid samples are not suitable for electrophoresis, the enzyme was forced to leave the pores by the following procedure. First, the biocatalysts were suspended in the electrophoresis buffer solution (containing sodium dodecyl sulfate, mercaptoethanol, bromophenol blue, tris buffer pH 6.8 and glycerol) and boiled for 10 min. In such denaturing conditions including the split of disulfide bonds, the tertiary structure of the protein should be lost and the random coil chain should then be easily released from the pores. The supernatants of these suspensions were withdrawn and run in 10 % SDS-PAGE electrophoresis.