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in Wiley Online Library (wileyonlinelibrary.com).The purification of different components of air, such as oxygen, nitrogen, and argon, is an important industrial process. Pressure swing adsorption (PSA) is surpassing the traditional cryogenic distillation for many air separation applications, because of its lower energy consumption. Unfortunately, the oxygen product purity in an industrial PSA process is typically limited to 95% due to the presence of argon which always shows the same adsorption equilibrium properties as oxygen on most molecular sieves. Recent work investigating the adsorption of nitrogen, oxygen and argon on the surface of silverexchanged Engelhard Titanosilicate-10 (ETS-10), indicates that this molecular sieve is promising as an adsorbent capable of producing high-purity oxygen. High-purity oxygen (99.7þ%) was generated using a bed of Ag-ETS-10 granules to separate air (78% N 2 , 21% O 2 , 1% Ar) at 25 C and 100 kPa, with an O 2 recovery rate greater than 30%. V V C 2012 American Institute of Chemical Engineers AIChE J, 59: 982-987, 2013 Compressed air (a mixture of 78% N 2 , 21% O 2 and 1% Ar) was introduced into a column containing 130 g of pelletized Ag-ETS-10 (sieved to a size between 0.28-0.84 mm) at a flow rate of 126 mL/min (bed volume 150 mL). Composition of the outlet gas was determined by GC analysis.

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Imine reductases (IREDs) are increasingly identified and characterized for the reduction of imines and reductive amination of ketones. However, their practical application is still limited due to the low activity and poor stability of native enzymes. Herein, we developed an engineered IRED through three rounds of evolution from wild-type Streptomyces clavuligerus. The specific activity of the engineered enzyme, ScIRED-R3-V4, was increased >100-fold, and stability was increased >270-fold. Using the more active and stable ScIRED-R3-V4, 80 g L–1 cyclic imine 2-(2,5-difluorophenyl)-pyrroline was completely reduced, producing kilogram quantities of a key chiral intermediate of larotrectinib in 82.5% yield, with >99.5% enantiomeric excess and a space–time yield of 352 g L–1 day–1. In addition, crystal structures of enzyme–substrate complexes and molecular dynamics simulations were conducted to gain insight into the molecular mechanism for improved enzyme performance. The significantly improved process demonstrated the potential of the engineered IRED in industrial applications.