Integration of Ion Exchange Resin Materials into Downstream-Processing
of an Imine Reductase (IREDs)-Catalyzed Reaction
Abstract
In this study an ion exchange resin-based downstream-processing approach
for imine reductase (IRED)-catalyzed reactions was investigated. As a
model reaction, 2 methylpyrroline was converted to its corresponding
product (S)-2-methylpyrrolodine with >99% of
conversion by the (S)-selective IRED from Paenibacillus
elgii B69. Under optimized reaction conditions full conversion was
achieved using a substrate concentration of 150
mmol·L-1 and 500 mmol·L-1 of
D-glucose. Seven commercially available cation and anion exchange resins
were studied with respect to their ability to recover the product from
the reaction solution. Without any pre-treatment, cation exchange resins
Amberlite IR-120(H), IRN-150, Dowex Monosphere 650C and Dowex Marathon
MSC showed high capacities (up to >90%). A 150
mL-preparative-scale reaction was performed yielding ca. 1 g product
with >99% purity. Any further purification steps, e.g. by
column chromatography or recrystallization, were not required.