Preparation of CLEAs of a recombinant NHase ES-NHT-118

Preparation of Cross-linked Enzyme Aggregates of Nitrile Hydratase ES-NHT-118 from E. coli by Macromolecular Cross-linking Agent

Liya Zhou, Haixia Mou, Jing Gao, Li Ma, Ying He and Yanjun Jiang

Chinese Journal of Chemical Engineering (in press)

http://dx.doi.org/10.1016/j.cjche.2016.08.027

Cross-linked enzyme aggregates (CLEAs) of nitrile hydratase (NHase) ES-NHT-118 from E. coli were prepared by using ammonium sulfate as precipitating agent followed by cross-linking with dextran polyaldehyde for the first time. In this process, egg white was added as an amine source to aid formation of CLEAs. The optimal conditions of the immobilization process were determined. Michaelis constants (K_m) of free NHase and NHase CLEAs were also determined. The NHase CLEAs exhibited increased stability at varied pH and temperature conditions compared to its free counterpart. When exposed to high concentrations of acrylamide, NHase CLEAs also exhibited effective catalytic activity.

 

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.