Editorial for the Special Issue: Thermophiles and Thermozymes

González-Siso, María-Isabel

doi:10.3390/microorganisms7030062

Cited by 6 publications

(3 citation statements)

References 9 publications

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“…The biochemical and structural analyses have revealed that thermostability is imparted by the concerted action of different structural features rather than a single unique feature ( Cobucci-Ponzano et al, 2010 ). Various stabilization factors such as a lower number of loops and cavities, increased number of ion pairs, large number of solvent molecules buried in cavities of the protein core, a higher number of proline residues in loops, a reduced ratio of protein surface area to protein volume, greater degree of oligomerization and an increased hydrophobic interactions have been predicted for the enhanced thermostability of thermozymes ( González-Siso, 2019 ). The composition of amino acids is also a determining factor in thermostability of enzymes.…”

Section: Factors Governing Thermostability and Kinetics Of Cellulasesmentioning

confidence: 99%

Progress in Ameliorating Beneficial Characteristics of Microbial Cellulases by Genetic Engineering Approaches for Cellulose Saccharification

2020

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Lignocellulosic biomass is a renewable and sustainable energy source. Cellulases are the enzymes that cleave β-1, 4-glycosidic linkages in cellulose to liberate sugars that can be fermented to ethanol, butanol, and other products. Low enzyme activity and yield, and thermostability are, however, some of the limitations posing hurdles in saccharification of lignocellulosic residues. Recent advancements in synthetic and systems biology have generated immense interest in metabolic and genetic engineering that has led to the development of sustainable technology for saccharification of lignocellulosics in the last couple of decades. There have been several attempts in applying genetic engineering in the production of a repertoire of cellulases at a low cost with a high biomass saccharification. A diverse range of cellulases are produced by different microbes, some of which are being engineered to evolve robust cellulases. This review summarizes various successful genetic engineering strategies employed for improving cellulase kinetics and cellulolytic efficiency.

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Section: Factors Governing Thermostability and Kinetics Of Cellulasesmentioning

confidence: 99%

Progress in Ameliorating Beneficial Characteristics of Microbial Cellulases by Genetic Engineering Approaches for Cellulose Saccharification

2020

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“…However, harsh conditions required for many industrial processes-such as high temperature and/or the use of organic (co)solvents-may impede the use of some enzymes. To address these drawbacks, using thermotolerant biocatalysts obtained from thermophilic organisms is an excellent alternative [20][21][22][23], as these thermozymes can efficiently work at very high temperatures [24,25] and are generally very resistant to organic solvent-promoted denaturation [26,27]. Among all the arsenal of enzymes available for being used in biotransformations, lipases (triacylglycerol hydrolases, EC 3.1.1.3) are one of the most frequently applied, as they are easily available, do not need cofactors and display a wide range of substrate recognition [28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Biocatalysis at Extreme Temperatures: Enantioselective Synthesis of both Enantiomers of Mandelic Acid by Transesterification Catalyzed by a Thermophilic Lipase in Ionic Liquids at 120 °C

Ramos-Martín¹,

Khiari²,

Alcántara³

et al. 2020

Catalysts

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The use of biocatalysts in organic chemistry for catalyzing chemo-, regio- and stereoselective transformations has become an usual tool in the last years, both at lab and industrial scale. This is not only because of their exquisite precision, but also due to the inherent increase in the process sustainability. Nevertheless, most of the interesting industrial reactions involve water-insoluble substrates, so the use of (generally not green) organic solvents is generally required. Although lipases are capable of maintaining their catalytic precision working in those solvents, reactions are usually very slow and consequently not very appropriate for industrial purposes. Increasing reaction temperature would accelerate the reaction rate, but this should require the use of lipases from thermophiles, which tend to be more enantioselective at lower temperatures, as they are more rigid than those from mesophiles. Therefore, the ideal scenario would require a thermophilic lipase capable of retaining high enantioselectivity at high temperatures. In this paper, we describe the use of lipase from Geobacillus thermocatenolatus as catalyst in the ethanolysis of racemic 2-(butyryloxy)-2-phenylacetic to furnish both enantiomers of mandelic acid, an useful intermediate in the synthesis of many drugs and active products. The catalytic performance at high temperature in a conventional organic solvent (isooctane) and four imidazolium-based ionic liquids was assessed. The best results were obtained using 1-ethyl-3-methyl imidazolium tetrafluoroborate (EMIMBF4) and 1-ethyl-3-methyl imidazolium hexafluorophosphate (EMIMPF6) at temperatures as high as 120 °C, observing in both cases very fast and enantioselective kinetic resolutions, respectively leading exclusively to the (S) or to the (R)-enantiomer of mandelic acid, depending on the anion component of the ionic liquid.

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“…Sequence and structural characteristics such as presence of insertions and deletions, proline substitutions, closer packing of water-accessible surface residues, and increase in helical contents and hydrogen bonds has also been suggested to contribute towards increase in the thermostability of thermophilic proteins [14][15][16]. Evidently, the characteristics providing thermostability to proteins can exist in various forms, and further understanding protein features and characteristics that likely contribute towards the thermostability of proteins is of much interest [13,17].Within the domain Bacteria, hyperthermophilic organisms are mainly present in three bacterial phyla viz. Aquificae, and Thermotogae [4,9,[18][19][20][21].…”

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confidence: 99%

Novel Sequence Feature of SecA Translocase Protein Unique to the Thermophilic Bacteria: Bioinformatics Analyses to Investigate Their Potential Roles

2019

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SecA is an evolutionarily conserved protein that plays an indispensable role in the secretion of proteins across the bacterial cell membrane. Comparative analyses of SecA homologs have identified two large conserved signature inserts (CSIs) that are unique characteristics of thermophilic bacteria. A 50 aa conserved insert in SecA is exclusively present in the SecA homologs from the orders Thermotogales and Aquificales, while a 76 aa insert in SecA is specific for the order Thermales and Hydrogenibacillus schlegelii. Phylogenetic analyses on SecA sequences show that the shared presence of these CSIs in unrelated groups of thermophiles is not due to lateral gene transfers, but instead these large CSIs have likely originated independently in these lineages due to their advantageous function. Both of these CSIs are located in SecA protein in a surface exposed region within the ATPase domain. To gain insights into the functional significance of the 50 aa CSI in SecA, molecular dynamics (MD) simulations were performed at two different temperatures using ADP-bound SecA from Thermotoga maritima. These analyses have identified a conserved network of water molecules near the 50 aa insert in which the Glu185 residue from the CSI is found to play a key role towards stabilizing these interactions. The results provide evidence for the possible role of the 50 aa CSI in stabilizing the binding interaction of ADP/ATP, which is required for SecA function. Additionally, the surface-exposed CSIs in SecA, due to their potential to make novel protein-protein interactions, could also contribute to the thermostability of SecA from thermophilic bacteria. organisms [11,13]. The increase in ion-pair interactions is due to a higher composition of charged amino acids such as lysine (Lys), arginine (Arg), glutamic acid (Glu) and asparagine (Asn) in the proteins from thermophilic bacteria when compared to those from mesophilic bacteria [11,13]. Sequence and structural characteristics such as presence of insertions and deletions, proline substitutions, closer packing of water-accessible surface residues, and increase in helical contents and hydrogen bonds has also been suggested to contribute towards increase in the thermostability of thermophilic proteins [14][15][16]. Evidently, the characteristics providing thermostability to proteins can exist in various forms, and further understanding protein features and characteristics that likely contribute towards the thermostability of proteins is of much interest [13,17].Within the domain Bacteria, hyperthermophilic organisms are mainly present in three bacterial phyla viz. Aquificae, and Thermotogae [4,9,[18][19][20][21]. The members from these phyla, which contain some of the most hyperthermophilic organisms known (e.g., Thermotoga maritima, Thermus aquaticus, and Aquifex aeolicus), are notable for their thermostable enzymes [1,2,5,9,22]. However, of these three phyla, while the phylum Aquificae is primarily comprised of thermophilic-hyperthermophilic organisms [18,20], in the other two phyla, hy...

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Editorial for the Special Issue: Thermophiles and Thermozymes

Cited by 6 publications

References 9 publications

Progress in Ameliorating Beneficial Characteristics of Microbial Cellulases by Genetic Engineering Approaches for Cellulose Saccharification

Progress in Ameliorating Beneficial Characteristics of Microbial Cellulases by Genetic Engineering Approaches for Cellulose Saccharification

Biocatalysis at Extreme Temperatures: Enantioselective Synthesis of both Enantiomers of Mandelic Acid by Transesterification Catalyzed by a Thermophilic Lipase in Ionic Liquids at 120 °C

Novel Sequence Feature of SecA Translocase Protein Unique to the Thermophilic Bacteria: Bioinformatics Analyses to Investigate Their Potential Roles

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