ijms-logo

Journal Browser

Journal Browser

Extreme Biocatalysts: From Basic Research to Biotechnological Applications

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Biochemistry".

Deadline for manuscript submissions: closed (21 July 2023) | Viewed by 20788

Special Issue Editors


E-Mail Website
Guest Editor
Department of Biotechnology, University of Verona, 37134 Verona, Italy
Interests: industrial enzymology; extremozymes; biocatalysis; biorefinery; biomass valorisation; enzymatic recycling of plastics; protein engineering; CRISPR-based applications; virus biotechnology
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Molecular Enzyme Technology and Biochemistry (MEB), University of Duisburg-Essen, Universitaetsstr. 5, 45141 Essen, Germany
Interests: extremophiles; archaea; Sulfolobus
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Biocatalysts show remarkable features that are revolutionizing, among other areas, the chemical, energy, agricultural, and pharmaceutical industries. Indeed, their use can pave the way to the design and optimization of sustainable industrial processes, which are at the very foundation of a timely and urgently needed shift towards a circular economy. The use of isolated enzymes or whole-cell biocatalysts has broadened the plethora of possible applications, allowing for the performance of chemo- and regioselective reactions, which is a major holdback in the chemical industry. Despite their vast potential in biotechnological applications, biocatalysts are currently used only for a limited number of industrial processes. This is mainly due to the narrow ranges of enzymatic stability towards critical parameters, such as temperature, pH, pressure, salinity, water activity, etc. Microorganisms thriving under extreme environmental conditions (collectively known as extremophiles), as well as the enzymes derived from them (extremozymes), can be used to overcome the aforementioned limitations.

With this Special Issue, we aim to collect original research articles, review articles, and short communications dealing with the study of extreme biocatalysts (both isolated enzymes and whole-cell biocatalysts). We welcome fundamental studies investigating the molecular basis underpinning the unique features of extremozymes as well as reports about their exploitation for biotechnological applications (industrial, diagnostic, environmental, etc.). Topics of interest include, but are not limited to, the following:

  • Discovery of new extremozymes (including thermophilic, psychrophilic, acidophilic, alkalophilic, halophilic, and polyextremophilic enzymes).
  • Functional and/or structural characterization of extremozymes
  • Development of enzyme assays for discovery, screening, and characterization.
  • Protein engineering for the optimization of extremozymes’ catalytical features.
  • Bioprospecting of extremozymes.
  • Extremozyme cascades to produce fine and bulk chemicals.
  • Discovery, design, optimization, and/or exploitation of extreme whole-cell biocatalysts.
  • Extremophiles as factories of commodity and specialty enzymes.
  • Extreme biocatalysts for circular economy applications.
Dr. Salvatore Fusco
Prof. Dr. Bettina Siebers
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. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. 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

  • Whole-cell biocatalysts
  • Extremozymes
  • Enzyme Assays
  • Protein Engineering
  • Extremophiles

Related Special Issue

Published Papers (11 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

0 pages, 9964 KiB  
Article
Lignocellulolytic Potential of Microbial Consortia Isolated from a Local Biogas Plant: The Case of Thermostable Xylanases Secreted by Mesophilic Bacteria
by Luca Bombardi, Andrea Salini, Martina Aulitto, Luca Zuliani, Marco Andreolli, Paola Bordoli, Annalaura Coltro, Nicola Vitulo, Claudio Zaccone, Silvia Lampis and Salvatore Fusco
Int. J. Mol. Sci. 2024, 25(2), 1090; https://doi.org/10.3390/ijms25021090 - 16 Jan 2024
Cited by 1 | Viewed by 1306
Abstract
Lignocellulose biomasses (LCB), including spent mushroom substrate (SMS), pose environmental challenges if not properly managed. At the same time, these renewable resources hold immense potential for biofuel and chemicals production. With the mushroom market growth expected to amplify SMS quantities, repurposing or disposal [...] Read more.
Lignocellulose biomasses (LCB), including spent mushroom substrate (SMS), pose environmental challenges if not properly managed. At the same time, these renewable resources hold immense potential for biofuel and chemicals production. With the mushroom market growth expected to amplify SMS quantities, repurposing or disposal strategies are critical. This study explores the use of SMS for cultivating microbial communities to produce carbohydrate-active enzymes (CAZymes). Addressing a research gap in using anaerobic digesters for enriching microbiomes feeding on SMS, this study investigates microbial diversity and secreted CAZymes under varied temperatures (37 °C, 50 °C, and 70 °C) and substrates (SMS as well as pure carboxymethylcellulose, and xylan). Enriched microbiomes demonstrated temperature-dependent preferences for cellulose, hemicellulose, and lignin degradation, supported by thermal and elemental analyses. Enzyme assays confirmed lignocellulolytic enzyme secretion correlating with substrate degradation trends. Notably, thermogravimetric analysis (TGA), coupled with differential scanning calorimetry (TGA-DSC), emerged as a rapid approach for saccharification potential determination of LCB. Microbiomes isolated at mesophilic temperature secreted thermophilic hemicellulases exhibiting robust stability and superior enzymatic activity compared to commercial enzymes, aligning with biorefinery conditions. PCR-DGGE and metagenomic analyses showcased dynamic shifts in microbiome composition and functional potential based on environmental conditions, impacting CAZyme abundance and diversity. The meta-functional analysis emphasised the role of CAZymes in biomass transformation, indicating microbial strategies for lignocellulose degradation. Temperature and substrate specificity influenced the degradative potential, highlighting the complexity of environmental–microbial interactions. This study demonstrates a temperature-driven microbial selection for lignocellulose degradation, unveiling thermophilic xylanases with industrial promise. Insights gained contribute to optimizing enzyme production and formulating efficient biomass conversion strategies. Understanding microbial consortia responses to temperature and substrate variations elucidates bioconversion dynamics, emphasizing tailored strategies for harnessing their biotechnological potential. Full article
Show Figures

Graphical abstract

17 pages, 2447 KiB  
Article
A Versatile Aldehyde: Ferredoxin Oxidoreductase from the Organic Acid Reducing Thermoanaerobacter sp. Strain X514
by Laura Sofie Nissen, Jimyung Moon, Lisa Hitschler and Mirko Basen
Int. J. Mol. Sci. 2024, 25(2), 1077; https://doi.org/10.3390/ijms25021077 - 16 Jan 2024
Viewed by 825
Abstract
Aldehyde:ferredoxin oxidoreductases (AORs) have been isolated and biochemically-characterized from a handful of anaerobic or facultative aerobic archaea and bacteria. They catalyze the ferredoxin (Fd)-dependent oxidation of aldehydes to acids. Recently, the involvement of AOR in the reduction of organic acids to alcohols with [...] Read more.
Aldehyde:ferredoxin oxidoreductases (AORs) have been isolated and biochemically-characterized from a handful of anaerobic or facultative aerobic archaea and bacteria. They catalyze the ferredoxin (Fd)-dependent oxidation of aldehydes to acids. Recently, the involvement of AOR in the reduction of organic acids to alcohols with electrons derived from sugar or synthesis gas was demonstrated, with alcohol dehydrogenases (ADHs) carrying out the reduction of the aldehyde to the alcohol (AOR-ADH pathway). Here, we describe the biochemical characterization of an AOR of the thermophilic fermentative bacterium Thermoanaerobacter sp. strain X514 (AORX514). The putative aor gene (Teth514_1380) including a 6x-His-tag was introduced into the genome of the genetically-accessible, related species Thermoanaerobacter kivui. The protein was purified to apparent homogeneity, and indeed revealed AOR activity, as measured by acetaldehyde-dependent ferredoxin reduction. AORX514 was active over a wide temperature (10 to 95 °C) and pH (5.5 to 11.5) range, utilized a wide variety of aldehydes (short and branched-chained, aliphatic, aromatic) and resembles archaeal sensu stricto AORs, as the protein is active in a homodimeric form. The successful, recombinant production of AORX514 in a related, well-characterized and likewise strict anaerobe paves the road towards structure-function analyses of this enzyme and possibly similar oxygen-sensitive or W/Mo-dependent proteins in the future. Full article
Show Figures

Figure 1

20 pages, 6043 KiB  
Article
Metagenomic Insights Reveal the Microbial Diversity and Associated Algal-Polysaccharide-Degrading Enzymes on the Surface of Red Algae among Remote Regions
by Xiaoqian Gu, Zhe Cao, Luying Zhao, Dewi Seswita-Zilda, Qian Zhang, Liping Fu and Jiang Li
Int. J. Mol. Sci. 2023, 24(13), 11019; https://doi.org/10.3390/ijms241311019 - 03 Jul 2023
Cited by 2 | Viewed by 1166
Abstract
Macroalgae and macroalgae-associated bacteria together constitute the most efficient metabolic cycling system in the ocean. Their interactions, especially the responses of macroalgae-associated bacteria communities to algae in different geographical locations, are mostly unknown. In this study, metagenomics was used to analyze the microbial [...] Read more.
Macroalgae and macroalgae-associated bacteria together constitute the most efficient metabolic cycling system in the ocean. Their interactions, especially the responses of macroalgae-associated bacteria communities to algae in different geographical locations, are mostly unknown. In this study, metagenomics was used to analyze the microbial diversity and associated algal-polysaccharide-degrading enzymes on the surface of red algae among three remote regions. There were significant differences in the macroalgae-associated bacteria community composition and diversity among the different regions. At the phylum level, Proteobacteria, Bacteroidetes, and Actinobacteria had a significantly high relative abundance among the regions. From the perspective of species diversity, samples from China had the highest macroalgae-associated bacteria diversity, followed by those from Antarctica and Indonesia. In addition, in the functional prediction of the bacterial community, genes associated with amino acid metabolism, carbohydrate metabolism, energy metabolism, metabolism of cofactors and vitamins, and membrane transport had a high relative abundance. Canonical correspondence analysis and redundancy analysis of environmental factors showed that, without considering algae species and composition, pH and temperature were the main environmental factors affecting bacterial community structure. Furthermore, there were significant differences in algal-polysaccharide-degrading enzymes among the regions. Samples from China and Antarctica had high abundances of algal-polysaccharide-degrading enzymes, while those from Indonesia had extremely low abundances. The environmental differences between these three regions may impose a strong geographic differentiation regarding the biodiversity of algal microbiomes and their expressed enzyme genes. This work expands our knowledge of algal microbial ecology, and contributes to an in-depth study of their metabolic characteristics, ecological functions, and applications. Full article
Show Figures

Figure 1

17 pages, 3066 KiB  
Article
Enhancing the Catalytic Activity of Thermo-Asparaginase from Thermococcus sibiricus by a Double Mesophilic-like Mutation in the Substrate-Binding Region
by Maria Dumina, Dmitry Zhdanov, Alexander Zhgun, Marina Pokrovskaya, Svetlana Aleksandrova, Alexander Veselovsky and Michael El’darov
Int. J. Mol. Sci. 2023, 24(11), 9632; https://doi.org/10.3390/ijms24119632 - 01 Jun 2023
Viewed by 1246
Abstract
L-asparaginases (L-ASNases) of microbial origin are the mainstay of blood cancer treatment. Numerous attempts have been performed for genetic improvement of the main properties of these enzymes. The substrate-binding Ser residue is highly conserved in L-ASNases regardless of their origin or type. However, [...] Read more.
L-asparaginases (L-ASNases) of microbial origin are the mainstay of blood cancer treatment. Numerous attempts have been performed for genetic improvement of the main properties of these enzymes. The substrate-binding Ser residue is highly conserved in L-ASNases regardless of their origin or type. However, the residues adjacent to the substrate-binding Ser differ between mesophilic and thermophilic L-ASNases. Based on our suggestion that the triad, including substrate-binding Ser, either GSQ for meso-ASNase or DST for thermo-ASNase, is tuned for efficient substrate binding, we constructed a double mutant of thermophilic L-ASNase from Thermococcus sibiricus (TsA) with a mesophilic-like GSQ combination. In this study, the conjoint substitution of two residues adjacent to the substrate-binding Ser55 resulted in a significant increase in the activity of the double mutant, reaching 240% of the wild-type enzyme activity at the optimum temperature of 90 °C. The mesophilic-like GSQ combination in the rigid structure of the thermophilic L-ASNase appears to be more efficient in balancing substrate binding and conformational flexibility of the enzyme. Along with increased activity, the TsA D54G/T56Q double mutant exhibited enhanced cytotoxic activity against cancer cell lines with IC90 values from 2.8- to 7.4-fold lower than that of the wild-type enzyme. Full article
Show Figures

Figure 1

13 pages, 2113 KiB  
Article
Production of Modified Nucleosides in a Continuous Enzyme Membrane Reactor
by Isabel Thiele, Heba Yehia, Niels Krausch, Mario Birkholz, Mariano Nicolas Cruz Bournazou, Azis Boing Sitanggang, Matthias Kraume, Peter Neubauer and Anke Kurreck
Int. J. Mol. Sci. 2023, 24(7), 6081; https://doi.org/10.3390/ijms24076081 - 23 Mar 2023
Cited by 3 | Viewed by 1829
Abstract
Nucleoside analogues are important compounds for the treatment of viral infections or cancers. While (chemo-)enzymatic synthesis is a valuable alternative to traditional chemical methods, the feasibility of such processes is lowered by the high production cost of the biocatalyst. As continuous enzyme membrane [...] Read more.
Nucleoside analogues are important compounds for the treatment of viral infections or cancers. While (chemo-)enzymatic synthesis is a valuable alternative to traditional chemical methods, the feasibility of such processes is lowered by the high production cost of the biocatalyst. As continuous enzyme membrane reactors (EMR) allow the use of biocatalysts until their full inactivation, they offer a valuable alternative to batch enzymatic reactions with freely dissolved enzymes. In EMRs, the enzymes are retained in the reactor by a suitable membrane. Immobilization on carrier materials, and the associated losses in enzyme activity, can thus be avoided. Therefore, we validated the applicability of EMRs for the synthesis of natural and dihalogenated nucleosides, using one-pot transglycosylation reactions. Over a period of 55 days, 2′-deoxyadenosine was produced continuously, with a product yield >90%. The dihalogenated nucleoside analogues 2,6-dichloropurine-2′-deoxyribonucleoside and 6-chloro-2-fluoro-2′-deoxyribonucleoside were also produced, with high conversion, but for shorter operation times, of 14 and 5.5 days, respectively. The EMR performed with specific productivities comparable to batch reactions. However, in the EMR, 220, 40, and 9 times more product per enzymatic unit was produced, for 2′-deoxyadenosine, 2,6-dichloropurine-2′-deoxyribonucleoside, and 6-chloro-2-fluoro-2′-deoxyribonucleoside, respectively. The application of the EMR using freely dissolved enzymes, facilitates a continuous process with integrated biocatalyst separation, which reduces the overall cost of the biocatalyst and enhances the downstream processing of nucleoside production. Full article
Show Figures

Figure 1

15 pages, 2582 KiB  
Article
Insight into CAZymes of Alicyclobacillus mali FL18: Characterization of a New Multifunctional GH9 Enzyme
by Miriam Carbonaro, Martina Aulitto, Giovanni Gallo, Patrizia Contursi, Danila Limauro and Gabriella Fiorentino
Int. J. Mol. Sci. 2023, 24(1), 243; https://doi.org/10.3390/ijms24010243 - 23 Dec 2022
Cited by 5 | Viewed by 2109
Abstract
In the bio-based era, cellulolytic and hemicellulolytic enzymes are biocatalysts used in many industrial processes, playing a key role in the conversion of recalcitrant lignocellulosic waste biomasses. In this context, many thermophilic microorganisms are considered as convenient sources of carbohydrate-active enzymes (CAZymes). In [...] Read more.
In the bio-based era, cellulolytic and hemicellulolytic enzymes are biocatalysts used in many industrial processes, playing a key role in the conversion of recalcitrant lignocellulosic waste biomasses. In this context, many thermophilic microorganisms are considered as convenient sources of carbohydrate-active enzymes (CAZymes). In this work, a functional genomic annotation of Alicyclobacillus mali FL18, a recently discovered thermo-acidophilic microorganism, showed a wide reservoir of putative CAZymes. Among them, a novel enzyme belonging to the family 9 of glycosyl hydrolases (GHs), named AmCel9, was identified; in-depth in silico analyses highlighted that AmCel9 shares general features with other GH9 members. The synthetic gene was expressed in Escherichia coli and the recombinant protein was purified and characterized. The monomeric enzyme has an optimal catalytic activity at pH 6.0 and has comparable activity at temperatures ranging from 40 °C to 70 °C. It also has a broad substrate specificity, a typical behavior of multifunctional cellulases; the best activity is displayed on β-1,4 linked glucans. Very interestingly, AmCel9 also hydrolyses filter paper and microcrystalline cellulose. This work gives new insights into the properties of a new thermophilic multifunctional GH9 enzyme, that looks a promising biocatalyst for the deconstruction of lignocellulose. Full article
Show Figures

Figure 1

12 pages, 3240 KiB  
Article
Use of a Novel Extremophilic Xylanase for an Environmentally Friendly Industrial Bleaching of Kraft Pulps
by Nazaré Almeida, Valérie Meyer, Auphélia Burnet, Jeremy Boucher, David Talens-Perales, Susana Pereira, Petri Ihalainen, Thomas Levée, Julio Polaina, Michel Petit-Conil, Susana Camarero and Paula Pinto
Int. J. Mol. Sci. 2022, 23(21), 13423; https://doi.org/10.3390/ijms232113423 - 03 Nov 2022
Cited by 4 | Viewed by 1916
Abstract
Xylanases can boost pulp bleachability in Elemental Chlorine Free (ECF) processes, but their industrial implementation for producing bleached kraft pulps is not straightforward. It requires enzymes to be active and stable at the extreme conditions of alkalinity and high temperature typical of this [...] Read more.
Xylanases can boost pulp bleachability in Elemental Chlorine Free (ECF) processes, but their industrial implementation for producing bleached kraft pulps is not straightforward. It requires enzymes to be active and stable at the extreme conditions of alkalinity and high temperature typical of this industrial process; most commercial enzymes are unable to withstand these conditions. In this work, a novel highly thermo and alkaline-tolerant xylanase from Pseudothermotoga thermarum was overproduced in E. coli and tested as a bleaching booster of hardwood kraft pulps to save chlorine dioxide (ClO2) during ECF bleaching. The extremozyme-stage (EXZ) was carried out at 90 °C and pH 10.5 and optimised at lab scale on an industrial oxygen-delignified eucalyptus pulp, enabling us to save 15% ClO2 to reach the mill brightness, and with no detrimental effect on paper properties. Then, the EXZ-assisted bleaching sequence was validated at pilot scale under industrial conditions, achieving 25% ClO2 savings and reducing the generation of organochlorinated compounds (AOX) by 18%, while maintaining pulp quality and papermaking properties. Technology reproducibility was confirmed with another industrial kraft pulp from a mix of hardwoods. The new enzymatic technology constitutes a realistic step towards environmentally friendly production of kraft pulps through industrial integration of biotechnology. Full article
Show Figures

Figure 1

24 pages, 6531 KiB  
Article
Insights on Microbial Communities Inhabiting Non-Volcanic Hot Springs
by Juan-José Escuder-Rodríguez, María-Eugenia DeCastro, Almudena Saavedra-Bouza, Manuel Becerra and María-Isabel González-Siso
Int. J. Mol. Sci. 2022, 23(20), 12241; https://doi.org/10.3390/ijms232012241 - 13 Oct 2022
Cited by 3 | Viewed by 1721
Abstract
The northwest of Spain has an abundance of non-volcanic hot springs that, until recently, had only been used for thermalism activities. One of such hot springs, Muiño da Veiga, has now been explored using metagenomics to study the microbial community that inhabits these [...] Read more.
The northwest of Spain has an abundance of non-volcanic hot springs that, until recently, had only been used for thermalism activities. One of such hot springs, Muiño da Veiga, has now been explored using metagenomics to study the microbial community that inhabits these high-temperature circumneutral continental waters. Sequencing of the metagenome allowed the characterization of its composition, diversity, metabolic connections and potential as a source for thermozymes, as well as its ability to assemble MAGs. A diverse microbial community dominated by Bacteria domain members was revealed, particularly from the early-branching Aquificales group. The most abundant genus was Sulfurihydrogenibium, known for its implication in sulfur cycling and for forming mats that enable novel niches. The variety of primary producers with autotrophic pathways (and specifically the sulfur oxidizing pathway) expands the range of available nutrients, and the increase in biomass forms thicker mats, resulting in more available niches and broader microbial diversity. Nonetheless, certain metabolic pathways were attributed to less abundant members of the microbial community, reinforcing the idea that the rare biosphere plays important roles in the network of interactions present in an ecosystem and acts as genetic reservoirs. In addition, three of the assembled MAGs represent novel microbial diversity found in this hot spring. Moreover, the presence of enzymes and microorganisms with possible biotechnological applications was confirmed, including proteases, lipases and cell-wall degrading enzymes, pointing to the potential for the hot spring as a source for thermozymes. Full article
Show Figures

Figure 1

19 pages, 7316 KiB  
Article
Functional Characterization and Synthetic Application of Is2-SDR, a Novel Thermostable and Promiscuous Ketoreductase from a Hot Spring Metagenome
by Erica Elisa Ferrandi, Ivan Bassanini, Susanna Bertuletti, Sergio Riva, Chiara Tognoli, Marta Vanoni and Daniela Monti
Int. J. Mol. Sci. 2022, 23(20), 12153; https://doi.org/10.3390/ijms232012153 - 12 Oct 2022
Cited by 4 | Viewed by 1795
Abstract
In a metagenome mining-based search of novel thermostable hydroxysteroid dehydrogenases (HSDHs), enzymes that are able to selectively oxidize/reduce steroidal compounds, a novel short-chain dehydrogenase/reductase (SDR), named Is2-SDR, was recently discovered. This enzyme, found in an Icelandic hot spring metagenome, shared a high sequence [...] Read more.
In a metagenome mining-based search of novel thermostable hydroxysteroid dehydrogenases (HSDHs), enzymes that are able to selectively oxidize/reduce steroidal compounds, a novel short-chain dehydrogenase/reductase (SDR), named Is2-SDR, was recently discovered. This enzyme, found in an Icelandic hot spring metagenome, shared a high sequence similarity with HSDHs, but, unexpectedly, showed no activity in the oxidation of the tested steroid substrates, e.g., cholic acid. Despite that, Is2-SDR proved to be a very active and versatile ketoreductase, being able to regio- and stereoselectively reduce a diversified panel of carbonylic substrates, including bulky ketones, α- and β-ketoesters, and α-diketones of pharmaceutical relevance. Further investigations showed that Is2-SDR was indeed active in the regio- and stereoselective reduction of oxidized steroid derivatives, and this outcome was rationalized by docking analysis in the active site model. Moreover, Is2-SDR showed remarkable thermostability, with an apparent melting temperature (TM) around 75 °C, as determined by circular dichroism analysis, and no significant decrease in catalytic activity, even after 5 h at 80 °C. A broad tolerance to both water-miscible and water-immiscible organic solvents was demonstrated as well, thus, confirming the potential of this new biocatalyst for its synthetic application. Full article
Show Figures

Figure 1

Review

Jump to: Research

17 pages, 1611 KiB  
Review
Cold-Active Lipases and Esterases: A Review on Recombinant Overexpression and Other Essential Issues
by Adamu Idris Matinja, Nor Hafizah Ahmad Kamarudin, Adam Thean Chor Leow, Siti Nurbaya Oslan and Mohd Shukuri Mohamad Ali
Int. J. Mol. Sci. 2022, 23(23), 15394; https://doi.org/10.3390/ijms232315394 - 06 Dec 2022
Cited by 1 | Viewed by 1823
Abstract
Cold environments characterised by diverse temperatures close to or below the water freezing point dominate about 80% of the Earth’s biosphere. One of the survival strategies adopted by microorganisms living in cold environments is their expression of cold-active enzymes that enable them to [...] Read more.
Cold environments characterised by diverse temperatures close to or below the water freezing point dominate about 80% of the Earth’s biosphere. One of the survival strategies adopted by microorganisms living in cold environments is their expression of cold-active enzymes that enable them to perform an efficient metabolic flux at low temperatures necessary to thrive and reproduce under those constraints. Cold-active enzymes are ideal biocatalysts that can reduce the need for heating procedures and improve industrial processes’ quality, sustainability, and cost-effectiveness. Despite their wide applications, their industrial usage is still limited, and the major contributing factor is the lack of complete understanding of their structure and cold adaptation mechanisms. The current review looked at the recombinant overexpression, purification, and recent mechanism of cold adaptation, various approaches for purification, and three-dimensional (3D) crystal structure elucidation of cold-active lipases and esterase. Full article
Show Figures

Figure 1

18 pages, 367 KiB  
Review
Metabolic Potential of Halophilic Filamentous Fungi—Current Perspective
by Weronika Śliżewska, Katarzyna Struszczyk-Świta and Olga Marchut-Mikołajczyk
Int. J. Mol. Sci. 2022, 23(8), 4189; https://doi.org/10.3390/ijms23084189 - 10 Apr 2022
Cited by 13 | Viewed by 3372
Abstract
Salty environments are widely known to be inhospitable to most microorganisms. For centuries salt has been used as a food preservative, while highly saline environments were considered uninhabited by organisms, and if habited, only by prokaryotic ones. Nowadays, we know that filamentous fungi [...] Read more.
Salty environments are widely known to be inhospitable to most microorganisms. For centuries salt has been used as a food preservative, while highly saline environments were considered uninhabited by organisms, and if habited, only by prokaryotic ones. Nowadays, we know that filamentous fungi are widespread in many saline habitats very often characterized also by other extremes, for example, very low or high temperature, lack of light, high pressure, or low water activity. However, fungi are still the least understood organisms among halophiles, even though they have been shown to counteract these unfavorable conditions by producing multiple secondary metabolites with interesting properties or unique biomolecules as one of their survival strategies. In this review, we focused on biomolecules obtained from halophilic filamentous fungi such as enzymes, pigments, biosurfactants, and osmoprotectants. Full article
Back to TopTop