Submit to Catalysts Review for Catalysts Propose a Special Issue

Journal Menu

Journal Browser

► Journal Browser

Special Issue "New Advances in Chemoenzymatic Synthesis"

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Biocatalysis".

Deadline for manuscript submissions: closed (15 September 2023) | Viewed by 4729

Share This Special Issue

Special Issue Editors

Dr. Teodora Bavaro

E-Mail Website
Guest Editor

Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
Interests: chemoenzymatic synthesis; medicinal chemistry; biocatalysis; protein engineering
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Giovanna Speranza

E-Mail Website
Guest Editor

Department of Chemistry, University of Milan, Via Golgi 19, 20133 Milan, Italy
Interests: organic chemistry; chemoenzymatic synthesis; natural product chemistry; food chemistry

Special Issue Information

Dear Colleagues,

Chemoenzymatic strategies for the synthesis of complex molecules have recently enriched the field of organic chemistry.

Currently, various examples of the development of chemoenzymatic processes have been described, which have successfully replaced existing chemical processes thanks to the integrated approach of biocatalysis and traditional chemical synthesis. Biocatalysis has been used for laboratory scale and industrial production in order to obtain synthetic pathways characterized by fewer steps, less waste and efficient global synthesis in terms of yields, regio- and stereoselectivity, process robustness and safety. Under this paradigm, enzyme-catalyzed reactions and the flexibility of chemical derivatization are powerful tools for streamlining access to relevant bioactive molecules.

This Thematic Issue covers all aspects of the current applications of chemoenzymatic routes in the synthesis of organic compounds (pharmaceuticals, fine chemicals, food additives, flavors, fragrances) at both the laboratory and industrial scales.

Dr. Teodora Bavaro
Prof. Dr. Giovanna Speranza
Guest Editors

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 submissions that pass pre-check are 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 2700 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

chemoenzymatic processes
biocatalysis
organic synthesis
biologically active compounds

Published Papers (4 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

Jump to: Review

Open AccessFeature PaperArticle

Flexibility and Function of Distal Substrate-Binding Tryptophans in the Blue Mussel β-Mannanase MeMan5A and Their Role in Hydrolysis and Transglycosylation

and

Catalysts 2023, 13(9), 1281; https://doi.org/10.3390/catal13091281 - 07 Sep 2023

Viewed by 357

Abstract

β-Mannanases hydrolyze β-mannans, important components of plant and microalgae cell walls. Retaining β-mannanases can also catalyze transglycosylation, forming new β-mannosidic bonds that are applicable for synthesis. This study focused on the blue mussel (Mytilus edulis) GH5_10 β-mannanase MeMan5A, which contains two semi-conserved tryptophans (W240 and W281) in the distal subsite +2 of its active site cleft. Variants of MeMan5A were generated by replacing one or both tryptophans with alanines. The substitutions reduced the enzyme’s catalytic efficiency (k_cat/K_m using galactomannan) by three-fold (W281A), five-fold (W240A), or 20-fold (W240A/W281A). Productive binding modes were analyzed by ¹⁸O labeling of hydrolysis products and mass spectrometry. Results show that the substitution of both tryptophans was required to shift away from the dominant binding mode of mannopentaose (spanning subsites −3 to +2), suggesting that both tryptophans contribute to glycan binding. NMR spectroscopy and molecular dynamics simulations were conducted to analyze protein flexibility and glycan binding. We suggest that W240 is rigid and contributes to +2 subsite mannosyl specificity, while W281 is flexible, which enables stacking interactions in the +2 subsite by loop movement to facilitate binding. The substitutions significantly reduced or eliminated transglycosylation with saccharides as glycosyl acceptors but had no significant effect on reactions with alcohols. Full article

(This article belongs to the Special Issue New Advances in Chemoenzymatic Synthesis)

► Show Figures

Graphical abstract

Open AccessArticle

Design of a New Chemoenzymatic Process for Producing Epoxidized Monoalkyl Esters from Used Soybean Cooking Oil and Fusel Oil

and

Catalysts 2023, 13(3), 543; https://doi.org/10.3390/catal13030543 - 08 Mar 2023

Viewed by 1104

Abstract

The aim of this study was to produce epoxidized monoalkyl esters (EMAE), a valuable class of oleochemicals used in a wide range of products and industries, from used soybean cooking oil (USCO) and fusel oil via a three-step chemoenzymatic process. This process consists of a first enzymatic hydrolysis of USCO to produce free fatty acids (FFA). Here, five microbial lipases with different specificities were tested as biocatalysts. Full hydrolysis of USCO was obtained after a 180 min reaction time under vigorous stirring (1500 rpm) using a non-specific lipase from Candida rugosa (CRL). Then, monoalkyl esters (MAE) were produced via the esterification of FFA and fusel oil in a solvent-free system using the lipase Eversa^® Transform 2.0 (ET2.0) immobilized via physical adsorption on poly(styrenene-divinylbenzene) (PSty-DVB) beads as a biocatalyst. Different water removal strategies (closed and open reactors in the presence or absence of molecular sieves at 5% m.m⁻¹) on the reaction were evaluated. Maximum FFA conversions of 64.3 ± 2.3% (open reactor after a 30 min reaction time) and 73.5 ± 0.4% (closed reactor after a 45 min reaction time) were observed at 40 °C, using a stoichiometric FFA:fusel oil molar ratio (1:1), without molecular sieves, and 5 mg of immobilized protein per gram of reaction mixture. Under these conditions, maximum FFA conversion was only 30.2 ± 2.7% after a 210 min reaction time in a closed reactor using soluble lipase. Reusability tests showed better retention of the original activity of immobilized ET2.0 (around 82%) after eight successive batches of esterification reactions conducted in an open reactor. Finally, the produced MAE was epoxidized via the Prilezhaev reaction, a classical chemical epoxidation process, using hydrogen peroxide and formic acid as a homogeneous catalyst. The products were characterized by standard methods and identified using proton nuclear magnetic resonance (¹H NMR). Maximum unsaturated bond conversions into epoxy groups were at approximately 33%, with the experimental epoxy oxygen content (OOC_exp.) at 1.75–1.78%, and selectivity (S) at 0.81, using both MAEs produced (open or closed reactors). These results show that this new process is a promising approach for value-added oleochemical production from low-cost and renewable raw materials. Full article

(This article belongs to the Special Issue New Advances in Chemoenzymatic Synthesis)

► Show Figures

Figure 1

Review

Jump to: Research

Open AccessReview

Applications of Brewer’s Spent Grain Hemicelluloses in Biorefineries: Extraction and Value-Added Product Obtention

Aline Ruth Schmidt

Aline Perin Dresch

Sergio Luiz Alves Junior

João Paulo Bender

and

Helen Treichel

Catalysts 2023, 13(4), 755; https://doi.org/10.3390/catal13040755 - 15 Apr 2023

Cited by 1 | Viewed by 954

Abstract

A circular economy is imperative for environmental sustainability. In this context, biorefineries stand out as a means of production able to reduce the carbon footprint and the impact of global warming. Biorefineries may employ lignocellulosic biomass from various plant sources to produce bioproducts with the potential to replace fossil derivatives through synthesis by microorganisms without competing with food crops. Brewer’s spent grain (BSG), the residue of the brewery production process, is an option with potential for use, being a cheap raw material highly available throughout the year. The chemical composition of this biomass is quite variable, with significant amounts of hemicellulose, mainly consisting of xylose and arabinose monomers that can be technologically converted into value-added products such as xylooligosaccharides, xylitol, second-generation ethanol (2G ethanol), biofilms and furfural. To this end, catalysts are unusual in making biorefineries increasingly competitive in the market, selectively optimizing reactions and reducing the environmental impact of the production processes of these bioproducts. The present review addresses the primary methods for extracting and processing hemicelluloses from BSG using either biocatalysts (enzymes) or homogenous (acids, alkali, and salts) and heterogenous catalysts (solid acids and metal oxide) that can be used to pretreat the biomass and obtain the preferred byproducts. The state of the art of optimized catalysis mechanisms is also presented. Full article

(This article belongs to the Special Issue New Advances in Chemoenzymatic Synthesis)

► Show Figures

Figure 1

Open AccessReview

A Review on the Progress in Chemo-Enzymatic Processes for CO₂ Conversion and Upcycling

and

Catalysts 2023, 13(3), 611; https://doi.org/10.3390/catal13030611 - 17 Mar 2023

Viewed by 1356

Abstract

The increasing concentration of atmospheric CO₂ due to human activities has resulted in serious environmental issues such as global warming and calls for efficient ways to reduce CO₂ from the environment. The conversion of CO₂ into value-added compounds such as methane, formic acid, and methanol has emerged as a promising strategy for CO₂ utilization. Among the different techniques, the enzymatic approach based on the CO₂ metabolic process in cells presents a powerful and eco-friendly method for effective CO₂ conversion and upcycling. This review discusses the catalytic conversion of CO₂ using single and multienzyme systems, followed by various chemo-enzymatic processes to produce bicarbonates, bulk chemicals, synthetic organic fuel and synthetic polymer. We also highlight the challenges and prospects for future progress in CO₂ conversion via chemo-enzymatic processes for a sustainable solution to reduce the global carbon footprint. Full article

(This article belongs to the Special Issue New Advances in Chemoenzymatic Synthesis)

► Show Figures

Journal Menu

Journal Browser

Special Issue "New Advances in Chemoenzymatic Synthesis"

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (4 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI