Immobilized Whole Cells as Effective Catalysts for Chiral Alcohol Production

2009 ◽  
Vol 62 (9) ◽  
pp. 1034 ◽  
Author(s):  
Jeck Fei Ng ◽  
Stephan Jaenicke
Keyword(s):  
Flow Reactor ◽  
Batch Reactor ◽  
Enantiomeric Excess ◽  
Lactobacillus Brevis ◽  
Packed Bed ◽  
Alginate Beads ◽  
Packed Bed Reactor ◽  
Process Conditions ◽  
Alcohol Production ◽  
Whole Cells

Recombinant Escherichia coli overexpressing the gene LbADH, which encodes for an alcohol dehydrogenase from Lactobacillus brevis, was successfully transformed and cultured. The cells are able to catalyze the reduction of pro-chiral ketones, e.g. ethyl acetoacetate into R-(–)ethyl hydroxybutyrate (EHB) with high conversion and enantiomeric excess >99%. Immobilizing the whole cells in alginate beads leads to a catalyst with improved stability and ease of handling while maintaining the high activity of the free cells. The whole-cell catalyst was tested in a stirred batch reactor (CSTR) and in a continuously operated packed-bed reactor. An Mg2+ concentration of 2 mM was crucial for maintaining the activity of the biocatalyst. After a partial optimization of the process conditions, a productivity of 1.4 gEHB gwcw–1 h–1 could be maintained in a continuous flow reactor over a prolonged period of time.

scholarly journals Development of a bioreactor system for the remediation of endosulphan

2018 ◽  
Vol 2 (1) ◽  
pp. 1-8 ◽  
Author(s):  
K. Jesitha ◽  
P. S. Harikumar
Keyword(s):  
Detection Limit ◽  
Calcium Alginate ◽  
Packed Bed ◽  
Alginate Beads ◽  
Soil Samples ◽  
Packed Bed Reactor ◽  
Contaminated Water ◽  
Initial Concentration ◽  
Bioreactor System ◽  
Ca Alginate

Abstract A bioreactor system that consisted of Pseudomonas fluorescens cells immobilised in calcium-alginate beads was utilised to remediate endosulphan contaminated water and soil. A packed bed reactor system was designed for the bio-degradation of endosulphan in artificially spiked water samples (initial concentration of endosulphan: 350 µg/L). Reactor studies with cell-immobilised Ca-alginate beads were conducted after checking their efficiency through batch and column degradation studies. The results showed that the concentration of toxic isomers of endosulphan (endosulphan alpha and endosulphan beta) was below the limit in the bioreactor during the 7th day of the experiment. Experiments conducted with contaminated soil samples (initial concentration of endosulphan: 1,000 μg/kg) indicated that the toxic isomers of endosulphan degraded to below the detection limit within 10 days and monitoring of endosulphan residues on the 14th day revealed that almost complete degradation of metabolites of endosulphan had occurred. The bioreactor system designed can be scaled up for remediation of endosulphan in contaminated areas.

scholarly journals 3D Chitin Scaffolds from the Marine Demosponge Aplysina archeri as a Support for Laccase Immobilization and Its Use in the Removal of Pharmaceuticals

Biomolecules ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 646 ◽  
Author(s):  
Jakub Zdarta ◽  
Tomasz Machałowski ◽  
Oliwia Degórska ◽  
Karolina Bachosz ◽  
Andriy Fursov ◽  
...  
Keyword(s):  
Storage Stability ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Optimum Process ◽  
Process Conditions ◽  
Total Removal ◽  
Laccase Immobilization ◽  
Continuous Use ◽  
First Time ◽  
Thermal Stability Of

For the first time, 3D chitin scaffolds from the marine demosponge Aplysina archeri were used for adsorption and immobilization of laccase from Trametes versicolor. The resulting chitin–enzyme biocatalytic systems were applied in the removal of tetracycline. Effective enzyme immobilization was confirmed by scanning electron microscopy. Immobilization yield and kinetic parameters were investigated in detail, in addition to the activity of the enzyme after immobilization. The designed systems were further used for the removal of tetracycline under various process conditions. Optimum process conditions, enabling total removal of tetracycline from solutions at concentrations up to 1 mg/L, were found to be pH 5, temperature between 25 and 35 °C, and 1 h process duration. Due to the protective effect of the chitinous scaffolds and stabilization of the enzyme by multipoint attachment, the storage stability and thermal stability of the immobilized biomolecules were significantly improved as compared to the free enzyme. The produced biocatalytic systems also exhibited good reusability, as after 10 repeated uses they removed over 90% of tetracycline from solution. Finally, the immobilized laccase was used in a packed bed reactor for continuous removal of tetracycline, and enabled the removal of over 80% of the antibiotic after 24 h of continuous use.

scholarly journals Simulation of methanol production from residual biomasses in a Cu/ZnO/Al2O3 packed bed reactor

2020 ◽  
Author(s):  
Carlos Esteban Aristizabal-Alzate ◽  
Andrés Felipe Vargas-Ramírez ◽  
Pedro Nel Alvarado-Torres
Keyword(s):  
Pressure Drop ◽  
Heterogeneous System ◽  
Catalyst Deactivation ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Deactivation Model ◽  
Alcohol Production ◽  
Methanol Production ◽  
Ratio Effect ◽  
Agent Selection

This article aims to simulate an algorithm constructed in MATLAB to represent the catalytic conversion of SYNGAS into methanol in a packed-bed reactor, based on chemical kinetics for a heterogeneous system with a Cu/ZnO/Al2O3 as a catalyst, and complementary math and phenomenological models, as a pressure drop and catalyst deactivation. Model validation is developed, comparing reference results and the results by running the algorithm in MATLAB using a reference SYNGAS composition. Also, the constructed model considers a catalyst deactivation by sintering and pressure drop along the reactor.  Several parameters were evaluated to identify the pro conditions for methyl alcohol production; these parameters include the gasifying agent selection, the biomass and steam ratio effect, and the biomass origin.

Immobilization of pectinase from Aspergillus aculeatus in alginate beads and clarification of apple and umbu juices in a packed bed reactor

2018 ◽  
Vol 109 ◽  
pp. 9-18 ◽  
Author(s):  
Rodrigo Lira de Oliveira ◽  
Jônatas Lopes Dias ◽  
Osmar Soares da Silva ◽  
Tatiana Souza Porto
Keyword(s):  
Packed Bed ◽  
Alginate Beads ◽  
Packed Bed Reactor ◽  
Aspergillus Aculeatus

The Application of a Rotating Packed Bed Reactor for the Synthesis of High Viscosity Wax Ester

2021 ◽  
Vol 15 (3) ◽  
pp. 421-427
Author(s):  
Juntao Xu ◽  
Renwei Zhang ◽  
Changsheng Liu ◽  
Fang Wang ◽  
Kaili Nie ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Packed Bed ◽  
High Viscosity ◽  
Packed Bed Reactor ◽  
High Mass ◽  
Synthesis Process ◽  
Wax Ester ◽  
Process Conditions ◽  
Transfer Resistance ◽  
Rotating Packed Bed

Wax esters are high value-added products and widely used in a broad range of commercial fields. The enzymatic synthesis of wax ester from plant oil is more attractive than the traditional chemical method due to being environmental-friendly and limiting the use of hazardous chemicals. However, the high mass transfer resistance from the high viscous substrate leads to a low conversion and long reaction time in the continues stirred tank reactor (CSTR). The rotating packed bed reactor (RPBR) offers high mass transfer and can be used to enhance the enzymatic wax ester synthesis process. From the results, it could be concluded that the mass transfer was enhanced with the optimization of the centrifugal factor of the RPBR. Under the optimal process conditions, the wax ester yield of 96.4% was obtained after 4 hours reaction, and the half-life of the catalyst corresponded with 64 hours, while nine batches achieved of yields above 90%. The investigation proved that the RPBR is an attractive and effective reactor for heterogeneous bio-catalysis in high viscosity of 7.39~12.27 Cst at 40 °C.

scholarly journals Self-Immobilizing Biocatalysts Maximize Space–Time Yields in Flow Reactors

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 164 ◽  
Author(s):  
Theo Peschke ◽  
Patrick Bitterwolf ◽  
Silla Hansen ◽  
Jannis Gasmi ◽  
Kersten Rabe ◽  
...  
Keyword(s):  
Flow Reactor ◽  
Lactobacillus Brevis ◽  
Packed Bed ◽  
Cascade Reactions ◽  
Space Time ◽  
Flow Reactors ◽  
Great Utility ◽  
Platform Comparison ◽  
Cross Platform ◽  
Coated Surfaces

Maximizing space–time yields (STY) of biocatalytic flow processes is essential for the establishment of a circular biobased economy. We present a comparative study in which different biocatalytic flow reactor concepts were tested with the same enzyme, the (R)-selective alcohol dehydrogenase from Lactobacillus brevis (LbADH), that was used for stereoselective reduction of 5-nitrononane-2,8-dione. The LbADH contained a genetically encoded streptavidin (STV)-binding peptide to enable self-immobilization on STV-coated surfaces. The purified enzyme was immobilized by physisorption or chemisorption as monolayers on the flow channel walls, on magnetic microbeads in a packed-bed format, or as self-assembled all-enzyme hydrogels. Moreover, a multilayer biofilm with cytosolic-expressed LbADH served as a whole-cell biocatalyst. To enable cross-platform comparison, STY values were determined for the various reactor modules. While mono- and multilayer coatings of the reactor surface led to STY < 10, higher productivity was achieved with packed-bed reactors (STY ≈ 100) and the densely packed hydrogels (STY > 450). The latter modules could be operated for prolonged times (>6 days). Given that our approach should be transferable to other enzymes, we anticipate that compartmentalized microfluidic reaction modules equipped with self-immobilizing biocatalysts would be of great utility for numerous biocatalytic and even chemo-enzymatic cascade reactions under continuous flow conditions.

Sign in / Sign up

Export Citation Format

Share Document