Special Issue "Immobilized Biocatalysts"

A special issue of Catalysts (ISSN 2073-4344).

Deadline for manuscript submissions: 31 March 2018

Special Issue Editor

Guest Editor
Prof. Dr. Peter Grunwald

University of Hamburg, Department of Physical Chemistry, Grindelallee 117, 20146 Hamburg, Germany
Website | E-Mail
Interests: biocatalysis; enzymatic analysis; Environmental biotechnology

Special Issue Information

Dear Colleagues,

Biocatalysts—single enzymes or whole cells—have gained increasing importance in the last few decades as green alternatives to their chemical counterparts for a variety of industrial processes. They catalyze reactions with the advantage of superior chemo-, regio-, and stereo-specificity at mild conditions, thereby avoiding the production of larger amounts of waste. To prevent spoiling of the resulting products with protein the biocatalysts should be employed in an immobilized form. In contrast to the application of soluble enzymes, they enable a higher volume specific biocatalyst loading together with simplified downstream processing. In addition, they can be reused tantamount to reducing cost contribution to the final product. Immobilization may also contribute to an enhanced storage and operational stability compared to soluble biocatalysts.

Immobilized biocatalysts are—apart from application in the chemical/pharmaceutical industry—used as biosensors, in medical diagnoses, genomics and genome sequencing (next generation sequencing), for protein microarrays (tracking interactions and activities of proteins, drug screening, etc.), or enzyme biocomputing.

The activity (efficiency) of an immobilized biocatalyst depends on various properties of the carrier material such as particle size and shape, its chemical nature, density, porosity (mass transfer limitation of the compounds involved), pore-size distribution or the mechanical strength. In addition, suited immobilization supports aside from bearing functional groups on their surface should be hydrophilic, biocompatible, resistant to microbial attack, and readily available at a low cost. They are of inorganic or organic origin and include natural and synthetic polymers. Bioinspired scaffolds and nanostructured materials (nanoparticles (paramagnetic), nanofibers, nanotubes, graphene, nanocomposites) are also used for enzyme immobilization.

Traditional immobilization techniques comprise adsorption, covalent binding, crosslinking, and entrapment. Moreover, immobilization and chemical modification may be coupled with site-directed mutagenesis, and nanobiocatalysts are generated by biological assembly methods. For covalent, site-specific immobilization several chemical and enzymatic approaches have proven. A variety of surface analysis technologies exist to control enzyme immobilization.

Prof. Dr. Peter Grunwald
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Catalysts is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Immobilized Biocatalysts, application areas (industrial production of goods and chemicals, pharmaceuticals, biofuel) analytics, diagnoses, microarrays, biocomputing, biofuel cells, bioactive coatings
  • Immobilization techniques, -traditional, site-specific protein immobilization, enzyme-mediated immobilization, biological assembly methods, cascade reactions, protein scaffolds, self-assembly of enzyme nanostructures, multi-enzyme immobilization, immobilization and site-directed mutagenesis
  • Immobilization supports, -properties, (quantum dots, magnetic nanoparticles, nanorods, nanotubes, nanofibres, nanocomposites
  • inorganic and organic materials, natural and synthetic polymers), biosynthesis of nanoparticles
  • surface analysis technologies (atomic force spectroscopy, FRET, BRET, TEM, SPR, and others)
  • kinetics of immobilized biocatalysts.

Published Papers (4 papers)

View options order results:
result details:
Displaying articles 1-4
Export citation of selected articles as:

Research

Open AccessArticle Immobilization of Cellulase on a Functional Inorganic–Organic Hybrid Support: Stability and Kinetic Study
Catalysts 2017, 7(12), 374; doi:10.3390/catal7120374
Received: 7 November 2017 / Revised: 28 November 2017 / Accepted: 29 November 2017 / Published: 1 December 2017
PDF Full-text (1637 KB) | HTML Full-text | XML Full-text
Abstract
Cellulase from Aspergillus niger was immobilized on a synthesized TiO2–lignin hybrid support. The enzyme was effectively deposited on the inorganic–organic hybrid matrix, mainly via physical interactions. The optimal initial immobilization parameters, selected for the highest relative activity, were pH 5.0, 6
[...] Read more.
Cellulase from Aspergillus niger was immobilized on a synthesized TiO2–lignin hybrid support. The enzyme was effectively deposited on the inorganic–organic hybrid matrix, mainly via physical interactions. The optimal initial immobilization parameters, selected for the highest relative activity, were pH 5.0, 6 h process duration, and an enzyme solution concentration of 5 mg/mL. Moreover, the effects of pH, temperature, and number of consecutive catalytic cycles and the storage stability of free and immobilized cellulase were evaluated and compared. Thermal and chemical stability were significantly improved, while after 3 h at a temperature of 50 °C and pH 6.0, the immobilized cellulase retained over 80% of its initial activity. In addition, the half-life of the immobilized cellulase (307 min) was five times that of the free enzyme (63 min). After ten repeated catalytic cycles, the immobilized biocatalyst retained over 90% of its initial catalytic properties. This study presents a protocol for the production of highly stable and reusable biocatalytic systems for practical application in the hydrolysis of cellulose. Full article
(This article belongs to the Special Issue Immobilized Biocatalysts)
Figures

Figure 1

Open AccessArticle Approaching Immobilization of Enzymes onto Open Porous Basotect®
Catalysts 2017, 7(12), 359; doi:10.3390/catal7120359
Received: 17 October 2017 / Revised: 14 November 2017 / Accepted: 16 November 2017 / Published: 27 November 2017
PDF Full-text (2608 KB) | HTML Full-text | XML Full-text
Abstract
For the first time, commercial macroporous melamine formaldehyde foam Basotect® (BT) was used as a basic carrier material for both adsorptive and covalent enzyme immobilization. In order to access inherent amino groups, the Basotect® surface was pretreated with hydrochloric acid. The
[...] Read more.
For the first time, commercial macroporous melamine formaldehyde foam Basotect® (BT) was used as a basic carrier material for both adsorptive and covalent enzyme immobilization. In order to access inherent amino groups, the Basotect® surface was pretreated with hydrochloric acid. The resulting material revealed 6 nmol of superficial amino groups per milligram Basotect®. Different optimized strategies for tethering the laccase from Trametes versicolor and the lipase from Thermomyces lanuginosus onto the pre-treated Basotect® surface were studied. Particularly, for covalent immobilization, two different strategies were pursued: lipase was tethered via a cross-linking method using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and laccase was bound after functionalizing Basotect® with hydrophilic copolymer poly(ethylene-alt-maleic anhydride) (PEMA). Prior to laccase immobilization, the PEMA coating of Basotect® was verified by ATR-FTIR analysis. Subsequent quantification of available high-reactive PEMA anhydride moieties revealed an amount of 1028 ± 73 nmol per mg Basotect®. The surface-bound enzyme amounts were quantified as 4.1–5.8 μg per mg Basotect®. A theoretical surface-covered enzyme mass for the ideal case that an enzyme monolayer was immobilized onto the Basotect® surface was calculated and compared to the amount of adsorptive and covalently bound enzymes before and after treatment with SDS. Furthermore, the enzyme activities were determined for the different immobilization approaches, and the stability during storage over time and against sodium dodecyl sulfate treatment was monitored. Additionally, PEMA-BT-bound laccase was tested for the elimination of anthropogenic micropollutant bisphenol A from contaminated water in a cost-effective and environmentally-friendly way and resulted in a degradation rate higher than 80%. Full article
(This article belongs to the Special Issue Immobilized Biocatalysts)
Figures

Figure 1

Open AccessArticle Polyelectrolyte Complex Beads by Novel Two-Step Process for Improved Performance of Viable Whole-Cell Baeyer-Villiger Monoxygenase by Immobilization
Catalysts 2017, 7(11), 353; doi:10.3390/catal7110353
Received: 18 October 2017 / Revised: 10 November 2017 / Accepted: 13 November 2017 / Published: 21 November 2017
PDF Full-text (4337 KB) | HTML Full-text | XML Full-text
Abstract
A novel immobilization matrix for the entrapment of viable whole-cell Baeyer–Villiger monooxygenase was developed. Viable recombinant Escherichia coli cells overexpressing cyclohexanone monooxygenase were entrapped in polyelectrolyte complex beads prepared by a two-step reaction of oppositely-charged polymers including highly defined cellulose sulphate. Immobilized cells
[...] Read more.
A novel immobilization matrix for the entrapment of viable whole-cell Baeyer–Villiger monooxygenase was developed. Viable recombinant Escherichia coli cells overexpressing cyclohexanone monooxygenase were entrapped in polyelectrolyte complex beads prepared by a two-step reaction of oppositely-charged polymers including highly defined cellulose sulphate. Immobilized cells exhibited higher operational stability than free cells during 10 repeated cycles of Baeyer–Villiger biooxidations of rac-bicyclo[3.2.0]hept-2-en-6-one to the corresponding lactones (1R,5S)-3-oxabicyclo-[3.3.0]oct-6-en-3-one and (1S,5R)-2-oxabicyclo-[3.3.0]oct-6-en-3-one. The morphology of polyelectrolyte complex beads was characterised by environmental scanning electron microscopy; the spatial distribution of polymers in the beads and cell viability were examined using confocal laser scanning microscopy, and the texture was characterised by the mechanical resistance measurements. Full article
(This article belongs to the Special Issue Immobilized Biocatalysts)
Figures

Figure 1

Open AccessCommunication In-Situ Self-Assembly of Zinc/Adenine Hybrid Nanomaterials for Enzyme Immobilization
Catalysts 2017, 7(11), 327; doi:10.3390/catal7110327
Received: 16 October 2017 / Revised: 27 October 2017 / Accepted: 27 October 2017 / Published: 3 November 2017
PDF Full-text (3181 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In this study, a one-step and facile immobilization of enzymes by self-assembly of zinc ions and adenine in aqueous solution with mild conditions was reported. Enzymes, such as glucose oxidase (GOx) and horseradish peroxidase (HRP), could be efficiently encapsulated in Zn/adenine coordination polymers
[...] Read more.
In this study, a one-step and facile immobilization of enzymes by self-assembly of zinc ions and adenine in aqueous solution with mild conditions was reported. Enzymes, such as glucose oxidase (GOx) and horseradish peroxidase (HRP), could be efficiently encapsulated in Zn/adenine coordination polymers (CPs) with high loading capacity over 90%. When the enzyme was immobilized by CPs, it displayed high catalytic efficiency, high selectivity and enhanced stability due to the protecting effect of the rigid framework. As a result, the relative activity of Zn/adenine nano-CP-immobilized GOx increased by 1.5-fold at pH 3 and 4-fold at 70 to 90 °C, compared to free GOx. The immobilized GOx had excellent reusability (more than 90% relative activity after being reused eight times). Furthermore, the use of this system as a glucose biosensor was also demonstrated by co-immobilization of two enzymes, detecting glucose down to 1.84 µM with excellent selectivity. The above work indicated that in-situ self-assembly of Zn/adenine CPs could be a simple and efficient method for biocatalyst immobilization. Full article
(This article belongs to the Special Issue Immobilized Biocatalysts)
Figures

Back to Top