Novel Sol‐Gel Lipases by Designed Bioimprinting for Continuous‐Flow Kinetic Resolutions

Abstract

Abstract:The bioimprinting effect in sol-gel immobilization of lipases was studied to develop efficient novel immobilized biocatalysts with significantly improved properties for biotransformations in continuous-flow systems. The bioimprinting candidates were selected systematically among the substrate mimics already found in the active site of experimental lipase structures. Four lipases (Lipase AK, Lipase PS, CaLB and CrL) were immobilized by a sol-gel process with nine bioimprinting candidates using various combinations of tetraethoxysilane (TEOS), phenyltriethoxysilane (PhTEOS), octyltriethoxysilane (OcTEOS) and dimethyldiethylsilane (DMDEOS) as silica precursors. The biocatalytic properties of the immobilized lipases were characterized by enantiomer selective acylation of various racemic secondary alcohols in two different multisubstrate systems (mixture A: a series of alkan-2-ols rac-1a-e and mixture B: heptan-2-ol rac-1f and 1-phenylethanol rac1g). Except with Lipase AK, the most significant activity enhancement was found with the imprinting molecules already found as substrate mimics in Xray structures of various lipases. The synthetic usefulness of the best biocatalysts was demonstrated by the kinetic resolution of racemic 1-(thiophen-2-yl)ethanol (rac-1h) in batch and continuous-flow systems.

Bioimprinted lipases in PVA nanofibers as efficient immobilized biocatalysts

“…In a previous study, the bioimprinting effect of several organosilanes applied as silane precursors to form the solgel matrix was considered assuming their substrate analog function. 17 In this study the bioimprinting effect of organosilanes such as phenyltriethoxysilane (PTEOS), octyltriethoxysilane (OTEOS) has been clearly demonstrated.…”

“…22 In addition to the fact that the organosilane precursors were able to influence the sol-gel matrix structure, it was assumed that they could act as bioimprinting agents as well. 17 The fact that lipases could accept alkoxysilanes as substrates during oligomerization of dimethlydiethoxysilane (DMDEOS) supported this hypothesis, 23 but in sol-gel systems these influencing factors could not be isolated from each other. Therefore, in this study four different organosilanes (TEOS, PTEOS, OTEOS and DMDEOS) were investigated for the first time as bioimprinting additives -besides four well-known bioimprinting molecules (Brij 30, Tween 80, PEG 400 and PEG 1000) -to enhance the biocatalytic properties of lipases entrapped in PVA nanofibers.…”

“…[13][14][15] The mutual effect of bioimprinting influencing the activity and enantioselectivity of lipases was demonstrated by immobilizations using sol-gel entrapment. 16,17 The bioimprinting effect could be rationalized on the basis of the generally accepted hypothesis of the interfacial activation mechanism. The active site of many lipases in aqueous solution is covered by a flexible region of the enzyme molecule, often called as lid.…”

Immobilization of lipases from Rhizomucor miehei and Thermomyces lanuginosus by adsorption on variously grafted silica gels

“…Among the many available immobilization methods, including adsorption, covalent attachment to solid supports and entrapment within polymers [8][9][10][11], hydrophobic adsorption onto suitable carriers was found to be an efficient way not only for immobilization but also for the separation of lipases [12]. Lipases immobilized by various procedures proved to be useful both in batch mode and in continuous-flow biotransformations [13][14][15][16].…”

Biocatalysis in continuous-flow mode: A case-study in the enzymatic kinetic resolution of secondary alcohols via acylation and deacylation reactions mediated by Novozym 435®

“…Aldolases [10], amidases [11], transaminases [12], oxidases [13,14], peroxidases [15] are some enzymes that have been successfully applied to a continuous-flow approach. Additionally, lipase-mediated esterification [16][17][18][19][20][21], interesterification [22,23], transesterification [24][25][26] and enzymatic kinetic resolution (EKR) of racemic compounds [27][28][29][30][31][32], have demonstrated the potential of combining continuous-flow systems and biocatalysis.…”