Efficient and Selective Carboligation with Whole‐Cell Biocatalysts in Pickering Emulsion

Abstract

Pickering emulsions (PEs) are particle-stabilized multiphase systems with promising features for synthetic applications.D escribed here is an ovel, simplified set-up employing catalytically active whole cells for simultaneous emulsion stabilization and synthetic reaction. In the stereoselective carboligation of benzaldehyde to (R)-benzoin catalyzed by abenzaldehyde lyase in E. coli, the set-up yielded maximum substrate conversion within very short time,while economizing material demand and waste.F ormation and activity of freshly produced PEs were enhanced when the catalytic whole cells were covered with hydrophobic silicone prior to PE formation. Benchmarked against other easy-to-handle whole-cell biocatalysts in pure organic solvent, neat substrate,a na queous emulsion in substrate,and amicro-aquatic system, respectively, the cell-stabilized PE outperformed all other systems by far.

Single-Conidium Encapsulation in Oil-in-Water Pickering Emulsions at High Encapsulation Yield

“…Pickering emulsions were extensively studied in the 20th century. Their high colloidal stability and controllable droplet size make them particularly suitable for single-cell encapsulation ( Yaakov et al, 2018 ), ( Bashir et al, 2016 ), ( Chen et al, 2015 ), ( Röllig et al, 2019 ). The stability of Pickering emulsions is governed by different parameters including their particle concentration, the wettability of the particles (oil/water volume fraction), and destabilization mechanisms ( Ortiz et al, 2020 ).…”

Continuous Flow Bioamination of Ketones in Organic Solvents at Controlled Water Activity using Immobilized ω‐Transaminases

“…Oxidoreductases, including alcohol dehydrogenases and peroxidases as well as alcohol and phenol oxidases were found to be active in neat organic solvents in the 1980s, and further studies on oxidoreductases were conducted during this decade . Examples with lyases comprise hydroxynitrile lyases, cyclases, decarboxylases, hydroperoxide lyases and benzaldehyde lyases …”

Effect of Particle Wettability and Particle Concentration on the Enzymatic Dehydration of n‐Octanaloxime in Pickering Emulsions

“…In fact, Röllig et al. reported the stabilisation of emulsions with E. coli cells containing a lyase for the stereoselective carboligation of benzaldehyde to ( R )‐benzoin [43] . Herein, however, we prefer silica particles to be the sole emulsifier.…”

“…[42] As aresult, it can be surface-active at the oil-water interface.I nf act, Rçllig et al reported the stabilisation of emulsions with E. coli cells containing al yase for the stereoselective carboligation of benzaldehyde to (R)-benzoin. [43] Herein, however,w ep refer silica particles to be the sole emulsifier.Therefore,alow concentration of E. coli cells containing OxdB of 0.025 wt. %w as selected to prepare emulsions.…”