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Monday 7 March 2016

Formation of Nitrile Hydratase CLEAs in Mesoporous Silica

Formation of Nitrile Hydratase Cross-Linked Enzyme Aggregates in Mesoporous Onion-like Silica: Preparation and Catalytic Properties
Jing Gao, Qi Wang, Yanjun Jiang*, Junkai Gao, Zhihua Liu, Liya Zhou, and Yufei Zhang,
Ind. Eng. Chem. Res., 2015, 54 (1), pp 83–90

Nitrile hydratase CLEAs) were formed in mesoporous onion-like silica (NHase-CLEAs@MOS) by using macromolecular dextran polyaldehyde as a cross-linker through the carrier-bound CLEAs method. Effect of pH, thermal and storage stability, and kinetic parameters of NHase-CLEAs@MOS were also studied. The maximum amount of NHase absorbed in MOS was 535 mg/g. Under optimized conditions, the maximum activity recovery of NHase-CLEAs@MOS was 48.2%. The stabilities of NHase-CLEAs@MOS were improved significantly compared to the NHase@MOS prepared by physical adsorption and free NHase.

Enzymatic cascade synthesis of (S)-2-hydroxycarboxylic amides and acids using a hydroxynitrile lyase, nitrile-active enzymes and an amidase

This review (Journal of Molecular Catalysis B: Enzymatic, 114, 2015, 25–30) by van Rantwijk and Stolz covers the bienzymatic conversion of aldehydes into enantiomerically pure hydroxycarboxylic acids and amides via an enzymatic cascade of hydrocyanation and nitrile hydration/hydrolysis. It compares results obtained via cross-linked enzyme aggregates (CLEAs) as well as whole-cell Escherichia coli expressing two enzymes. It highlights these methods’ potential for yielding near-quantitative yield and ee at synthetically relevant concentrations.