Linum usitatissimum Hydroxynitrile Lyase Cross‐Linked Enzyme Aggregates: A Recyclable Enantioselective Catalyst

Abstract

An immobilized form of the hydroxynitrile lyase from Linum usitatissimum (LuHNL) as crosslinked enzyme aggregate (CLEA) with high specific activity (303.5 U/g) and recovery (33%) was developed. Molecular imprinting using 2-butanone as additive in the immobilization process improved the synthetic activity of the biocatalyst. LuCLEA could be partially recycled for the synthesis of (R)-2-butanone cyanohydrin on a preparative scale over two batches. The enantioenriched cyanohydrin obtained was further hydrolyzed to give (R)-2-hydroxy-2-methylbutyric acid in 85% yield (from 2-butanone) and 87% ee.

New stabilized FastPrep-CLEAs for sialic acid synthesis

“…This strongly supports the value of using hardened CLEAs in combination with the FastPrep system for dispersion, to yield FP-CLEAs with excellent resistance to mechanical stress, allowing high recoveries of catalyst after many cycles of use. These ten cycles without loss of activity in CLEAs has also been described for lipase (Gupta et al, 2009), R-oxynitrilase (van Langen et al, 2005 and acetyl xylan esterase (Montoro-García et al, 2010), but contrast with the four reuses possible with hydroxynitrile lyase (Cabirol et al, 2008) or subtilisin (Sangeetha and Abraham, 2008).…”

“…S1b), whereas in the presence of BSA (BSA-CLEAs), they were organized as a network of 'branches' separated by pores, with a spongy and 'holey' morphology ( Fig. S1c), which maximizes the catalyst surface available for reaction, while minimizing the diffusion effect within the catalyst, as has been previously described for hydroxynitrile lyase (Cabirol et al, 2008). These images clearly show the transition from the ''classical chemical aggregates'' of AS-CLEAs, previously reported in the literature (Tyagi et al, 1999), to a uniform porous mesh (BSA-CLEAs), which is somewhat between the ball-like structure appearance (type 1) and the less structured form (type 2) described by Schoevaart et al (2004).…”

Production of Hydroxynitrile Lyase from Davallia tyermannii (DtHNL) in Komagataella phaffii and Its Immobilization as a CLEA to Generate a Robust Biocatalyst

“…HNL–CLEA preparations have already been developed and significant improvement of the biocatalytic processes has been demonstrated. For instance, Lu HNL–CLEA was employed on a preparative scale for the synthesis of ( R )‐2‐hydroxy‐2‐methylbutyric acid in 85 % yield and 87 % ee . Other examples of successful HNL–CLEAs are Pa HNL, Me HNL, and Hb HNL …”

An Enzymatic Toolbox for the Kinetic Resolution of 2‐(Pyridin‐x‐yl)but‐3‐yn‐2‐ols and Tertiary Cyanohydrins

“…In addition, the stereodifferentiation becomes considerably more difficult when ketones are the substrates. [12,13] The alternative chemical asymmetric syntheses only give reasonable results with methyl ketones and are thus rather limited. [6,9] Ketone-derived cyanohydrins are tertiary alcohols.…”