Improvement and Application of Microbial Hydrolytic Enzymes

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Applied Biosciences and Bioengineering".

Deadline for manuscript submissions: closed (18 February 2022) | Viewed by 12546

Special Issue Editor

College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon 255, Korea
Interests: cell wall-lytic enzyme; protease; esterase; chitinase; molecular enzymology; metagenome; microorganism
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Special Issue Information

Dear Colleagues,

We are inviting manuscript submissions to the Special Issue on Improvement and Application of Microbial Hydrolytic Enzymes.

Microbial hydrolytic enzymes are diverse and of interest in various industrial areas. Among them, cell wall-lytic enzymes have been extensively investigated. Cell walls are mainly composed of cellulose, hemicellulose, and pectin. Cellulose has a linear structure of β-1,4-linked D-glucose units and makes a complex structure with hemicellulose via non-covalent interactions. Hemicelluloses are backboned with xylan, mannan and glucomannans, or xyloglucan. Pectins are present as homogalacturonan, xylogalacturonan, and rhamnogalacturonan. Cell wall-lytic (or degrading) enzymes hydrolyze these backbones and efficient biocatalysts used in various fields such as the pharmaceutical, food, beverage, paper and pulp, poultry, biofuel, flavors, detergents, and textile industries. Besides, other hydrolytic enzymes such as proteases, esterases, and chitinases have been researched from microbial sources. With increasing demand, properties of the enzymes have been improved with many types of methods such as directed evolution and mutation based on rational design including molecular simulations. The methods are applied to increase enzyme thermostability, catalytic activity, substrate affinity, and others.

In this Special Issue, we invite eminent submissions exploring cutting-edge research and recent advances in the fields of Improvement and Application of Microbial Hydrolytic Enzymes produced from microbial sources. Both experimental articles and comprehensive reviews are welcome.

Prof. Dr. Hoon Kim
Guest Editor

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Keywords

  • Cell wall lytic enzyme
  • Protease
  • Esterase
  • Chitinase
  • Microbial source
  • Production
  • Molecular structure of enzyme
  • Improvement of enzyme property
  • Rational design
  • Application

Published Papers (4 papers)

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Research

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17 pages, 3126 KiB  
Article
Characterization of a Novel Family IV Esterase Containing a Predicted CzcO Domain and a Family V Esterase with Broad Substrate Specificity from an Oil-Polluted Mud Flat Metagenomic Library
by Jong Eun Park, Geum Seok Jeong, Hyun Woo Lee, Sung Kyum Kim, Jungho Kim and Hoon Kim
Appl. Sci. 2021, 11(13), 5905; https://doi.org/10.3390/app11135905 - 25 Jun 2021
Cited by 7 | Viewed by 2004
Abstract
Two novel esterase genes, est2L and est4L, were identified from a previously constructed metagenomic library derived from an oil-polluted mud flat sample. The encoded Est2L and Est4L were composed of 839 and 267 amino acids, respectively, without signal peptides. Est2L was a [...] Read more.
Two novel esterase genes, est2L and est4L, were identified from a previously constructed metagenomic library derived from an oil-polluted mud flat sample. The encoded Est2L and Est4L were composed of 839 and 267 amino acids, respectively, without signal peptides. Est2L was a unique fusion type of protein composed of two domains: a domain of the CzcO superfamily, associated with a cationic diffusion promoter with CzcD, and a domain of the acetylesterase superfamily, belonging to family IV with conserved motifs, such as HGG, GXSAG, and GXPP. Est2L was the first fused esterase with a CzcO domain. Est4L belonged to family V with GXS, GXSMGG, and PTL motifs. Native Est2L and Est4L were found to be in dimeric and tetrameric forms, respectively. Est2L and Est4L showed the highest activities at 60 °C and 50 °C, respectively, and at a pH of 10.0. Est2L preferred short length substrates, especially p-nitrophenyl (pNP)-acetate, with moderate butyrylcholinesterase activity, whereas Est4L showed the highest activity with pNP-decanoate and had broad specificity. Significant effects were not observed in Est2L from Co2+ and Zn2+, although Est2L contains the domain CzcD. Est2L and Est4L showed high stabilities in 30% methanol and 1% Triton X-100. These enzymes could be used for a variety of applications, such as detergent and mining processing under alkaline conditions. Full article
(This article belongs to the Special Issue Improvement and Application of Microbial Hydrolytic Enzymes)
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13 pages, 1210 KiB  
Article
Enhanced Production of Carboxymethylcellulase by Recombinant Escherichia coli Strain from Rice Bran with Shifts in Optimal Conditions of Aeration Rate and Agitation Speed on a Pilot-Scale
by Chung-Il Park, Jae-Hong Lee, Jianhong Li and Jin-Woo Lee
Appl. Sci. 2019, 9(19), 4083; https://doi.org/10.3390/app9194083 - 30 Sep 2019
Viewed by 2829
Abstract
The optimal conditions including the aeration rate and agitation speed of bioreactors for the production of carboxymethylcellulase (CMCase) by a recombinant Escherichia coli KACC 91335P, expressing CMCase gene of B. velezensis A-68, were different from those for its cell growth. The enhanced production [...] Read more.
The optimal conditions including the aeration rate and agitation speed of bioreactors for the production of carboxymethylcellulase (CMCase) by a recombinant Escherichia coli KACC 91335P, expressing CMCase gene of B. velezensis A-68, were different from those for its cell growth. The enhanced production of CMCase by E. coli KACC 91335P with the conventional multistage process needs at least two bioreactors. Shifts in the optimal conditions of the aeration rate and agitation speed of the bioreactor from the cell growth of E. coli KACC 91335P to those for its production of CMCase were investigated for development of the simple and economic process with the high productivity and low cost. The production of CMCase by E. coli KACC 91335P with shifts in the optimal conditions of the aeration rate and agitation speed from the cell growth to its production of CMCase in a 100 L pilot-scale bioreactor was 1.36 times higher than that with a fixed optimal conditions of the aeration rate and agitation speed for the production of CMCase and it was even 1.54 times higher than that with a fixed optimal conditions of the aeration rate and agitation speed for cell growth. The best time for the shift in the optimal conditions was found to be the mid-log phase of cell growth. Owing to the mixed-growth-associated production of CMCase by E. coli KACC 91335P, shifts in the optimal conditions of the aeration rate and agitation speed of bioreactors from the cell growth to its production of CMCase seemed to result in relatively more cells for the participation in its production of CMCase, which in turn enhanced its production of CMCase. The process with a simple control for shifts in the aeration rate and agitation speed of a bioreactor for the enhanced production of CMCase by E. coli KACC 91335P on the pilot-scale can be directly applied to the industrial-scaled production of cellulase. Full article
(This article belongs to the Special Issue Improvement and Application of Microbial Hydrolytic Enzymes)
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12 pages, 1350 KiB  
Article
Molecular Characterization of an Endo-β-1,4-Glucanase, CelAJ93, from the Recently Isolated Marine Bacterium, Cellulophaga sp. J9-3
by Da Som Kim, Won-Jae Chi and Soon-Kwang Hong
Appl. Sci. 2019, 9(19), 4061; https://doi.org/10.3390/app9194061 - 28 Sep 2019
Cited by 5 | Viewed by 2074
Abstract
A novel cellulase was characterized from a newly isolated marine bacterium, strain J9-3. Phylogenetic analysis based on the 16S rRNA gene revealed that strain J9-3 belonged to the genus Cellulophaga, and thus, it was named Cellulophaga sp. J9-3. An extracellular cellulase was purified [...] Read more.
A novel cellulase was characterized from a newly isolated marine bacterium, strain J9-3. Phylogenetic analysis based on the 16S rRNA gene revealed that strain J9-3 belonged to the genus Cellulophaga, and thus, it was named Cellulophaga sp. J9-3. An extracellular cellulase was purified from cell-free culture broth of J9-3 cultured in Marine Broth containing 0.2% carboxymethylcellulose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the protein revealed a single band with an apparent molecular weight (Mw) of 35 kDa. Based on the NH2-terminal amino acid sequence (N-N-T-E-Q-T-V-V-D-A-Y-G), the gene (named celAJ93) encoding the protein was identified from J9-3 genomic sequencing data. CelAJ93 was expected to be translated into a premature protein (359 amino acids) and then processed to a mature protein (307 amino acids, Mw = 34,951 Da), which is consistent with our results. CelAJ93 had high homology with many uncharacterized putative glycosyl hydrolases of the genus Cellulophaga and it was highly specific for carboxymethylcellulose and cellooligosaccharides under optimum conditions (pH 7.5, 60 °C). Co2+ completely recovered CelAJ93 activity that was severely inhibited by ethylenediaminetetraacetic acid (EDTA), indicating that CelAJ93 required Co2+ as a cofactor. Thus, CelAJ93 is a Co2+-dependent endo-β-1,4-glucanase that can hydrolyze carboxymethylcellulose and cellooligosaccharides into cellobiose at a relatively high temperature. Full article
(This article belongs to the Special Issue Improvement and Application of Microbial Hydrolytic Enzymes)
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Review

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24 pages, 2276 KiB  
Review
Green Production and Biotechnological Applications of Cell Wall Lytic Enzymes
by Manuel Benedetti, Federica Locci, Giovanna Gramegna, Francesco Sestili and Daniel V. Savatin
Appl. Sci. 2019, 9(23), 5012; https://doi.org/10.3390/app9235012 - 21 Nov 2019
Cited by 15 | Viewed by 4429
Abstract
Energy demand is constantly growing, and, nowadays, fossil fuels still play a dominant role in global energy production, despite their negative effects on air pollution and the emission of greenhouse gases, which are the main contributors to global warming. An alternative clean source [...] Read more.
Energy demand is constantly growing, and, nowadays, fossil fuels still play a dominant role in global energy production, despite their negative effects on air pollution and the emission of greenhouse gases, which are the main contributors to global warming. An alternative clean source of energy is represented by the lignocellulose fraction of plant cell walls, the most abundant carbon source on Earth. To obtain biofuels, lignocellulose must be efficiently converted into fermentable sugars. In this regard, the exploitation of cell wall lytic enzymes (CWLEs) produced by lignocellulolytic fungi and bacteria may be considered as an eco-friendly alternative. These organisms evolved to produce a variety of highly specific CWLEs, even if in low amounts. For an industrial use, both the identification of novel CWLEs and the optimization of sustainable CWLE-expressing biofactories are crucial. In this review, we focus on recently reported advances in the heterologous expression of CWLEs from microbial and plant expression systems as well as some of their industrial applications, including the production of biofuels from agricultural feedstock and of value-added compounds from waste materials. Moreover, since heterologous expression of CWLEs may be toxic to plant hosts, genetic strategies aimed in converting such a deleterious effect into a beneficial trait are discussed. Full article
(This article belongs to the Special Issue Improvement and Application of Microbial Hydrolytic Enzymes)
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