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Book ChapterDOI

Geobacillus and Anoxybacillus spp. from Terrestrial Geothermal Springs Worldwide: Diversity and Biotechnological Applications

TL;DR: This chapter contains a review of studies of geobacilli and anoxybacilli from terrestrial geothermal springs worldwide with special emphasis on their distribution and diversity, ecological significance, adaptive mechanisms, enzymes, and biotechnological potential.
Abstract: A large number of thermophilic representatives of the Geobacillus and Anoxybacillus genera have been isolated from geographically distant and physicochemically different environments, including high-, moderate-, and low-temperature habitats However, terrestrial hot springs are the main habitats for Geobacillus and Anoxybacillus species The members of these genera possess a variety of thermo-adaptive features that enable them to thrive at elevated temperatures Due to their ability to withstand harsh environmental conditions, geobacilli and anoxybacilli are a valuable source for provision of thermostable enzymes, such as amylases, lipases, proteases, etc, and other components Thermostable enzymes obtained from thermophilic bacilli have found a plethora of commercial applications due to their sturdiness and toughness in withstanding the heat generated in various biotechnological and industrial processes This chapter contains a review of studies of geobacilli and anoxybacilli from terrestrial geothermal springs worldwide with special emphasis on their distribution and diversity, ecological significance, adaptive mechanisms, enzymes, and biotechnological potential
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Journal ArticleDOI
TL;DR: This review explores the comprehensive application potential of extremophiles and extremozymes in biorefinery, which is partly due to their specificity and efficiency, and points out the necessity of accelerating the commercialization of extremzymes.
Abstract: The biorefining technology for biofuels and chemicals from lignocellulosic biomass has made great progress in the world. However, mobilization of laboratory research toward industrial setup needs to meet a series of criteria, including the selection of appropriate pretreatment technology, breakthrough in enzyme screening, pathway optimization, and production technology, etc. Extremophiles play an important role in biorefinery by providing novel metabolic pathways and catalytically stable/robust enzymes that are able to act as biocatalysts under harsh industrial conditions on their own. This review summarizes the potential application of thermophilic, psychrophilic alkaliphilic, acidophilic, and halophilic bacteria and extremozymes in the pretreatment, saccharification, fermentation, and lignin valorization process. Besides, the latest studies on the engineering bacteria of extremophiles using metabolic engineering and synthetic biology technologies for high-efficiency biofuel production are also introduced. Furthermore, this review explores the comprehensive application potential of extremophiles and extremozymes in biorefinery, which is partly due to their specificity and efficiency, and points out the necessity of accelerating the commercialization of extremozymes.

81 citations

Journal ArticleDOI
TL;DR: In this paper, the crystal structures of DnaK from Geobacillus kaustophilus HTA426 bound with ADP-Mg2+-Pi at 2.37A and the 70-kDa heat shock cognate protein from Rattus norvegicus (RnN) was found to have 3.5A.
Abstract: The 70-kDa heat shock proteins (Hsp70s) are highly conserved ATP-dependent molecular chaperones composed of an N-terminal nucleotide binding domain (NBD) and a C-terminal protein substrate binding domain (SBD) in a bilobate structure. Interdomain communication and nucleotide-dependent structural motions are critical for Hsp70 chaperone functions. Our understanding of these functions remains elusive due to insufficient structural information on intact Hsp70s that represent the different states of the chaperone cycle. We report here the crystal structures of DnaK from Geobacillus kaustophilus HTA426 bound with ADP-Mg2+-Pi at 2.37A and the 70-kDa heat shock cognate protein from Rattus norvegicus bound with ADP-Pi at 3.5A. The NBD and SBD in these structures are significantly separated from each other, and they might depict the ADP-bound conformation. Moreover, a Trp reporter was introduced at the potential interface region between NBD and the interdomain linker of GkDnaK to probe environmental changes. Results from fluorescence measurements support the notion that substrate binding enhances the domain-disjoining behavior of Hsp70 chaperones.

57 citations

Journal ArticleDOI
TL;DR: In this article, a high compatible thermoalkaliphilic lipase (TA) with detergents from new thermophilic bacterial strains utilizing fish wastes for industrial application was produced.

27 citations

Journal ArticleDOI
TL;DR: A new potent strain of thermophilic bacterium isolated from Sungai Klah Hot Spring Park in Perak, Malaysia for the first time is revealed and the high production of thermostable protease enzyme by G. thermoglucosidasius SKF4 highlighted the promising properties of this bacterium for industrial and biotechnological applications.
Abstract: Major progress in the fields of agriculture, industry, and biotechnology over the years has influenced the quest for a potent microorganism with favorable properties to be used in scientific research and industry. This study intended to isolate a new thermophilic-protease-producing bacterium and evaluate its growth and protease production under cultural conditions. Protease producing bacteria were successfully isolated from Sungai Klah Hot Spring Park in Perak, Malaysia, and coded as SKF4; they were promising protease producers. Based on microscopic, morphological, and 16S rRNA gene analysis, isolate SKF4 was identified as Geobacillus thermoglucosidasius SKF4. The process of isolating SKF4 to grow and produce proteases under different cultural conditions, including temperature, pH, NaCl concentration, carbon and nitrogen sources, and incubation time, was explored. The optimum cultural conditions observed for growth and protease production were at 60 to 65 °C of temperature, pH 7 to 8, and under 1% NaCl concentration. Further, the use of casein and yeast extract as the nitrogen sources, and sucrose and fructose as the carbon sources enhanced the growth and protease production of isolate SKF4. Meanwhile, isolate SKF4 reached maximum growth and protease production at 24 h of incubation time. The results of this study revealed a new potent strain of thermophilic bacterium isolated from Sungai Klah Hot Spring Park in Perak, Malaysia for the first time. The high production of thermostable protease enzyme by G. thermoglucosidasius SKF4 highlighted the promising properties of this bacterium for industrial and biotechnological applications.

20 citations


Cites background from "Geobacillus and Anoxybacillus spp. ..."

  • ...[43] suggested that the most important mechanistic determining factors of thermoadaptation in Bacilli are the adaptation of composition regarding the membrane lipids, heat shock membrane synthesis (HSPs), and the ability of the enzyme to adapt to produce molecular stability and structural Figure 4....

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  • ...[43] suggested that the most important mechanistic determining factors of thermoadaptation in Bacilli are the adaptation of composition regarding the membrane lipids, heat shock membrane synthesis (HSPs), and the ability of the enzyme to adapt to produce molecular stability and structural flexibility....

    [...]

Journal ArticleDOI
TL;DR: Bacilli isolated from high-altitude mineralized geothermal springs located within the territory of Armenia and Nagorno-Karabakh shared less than 91–97% sequence identity with their closest match in GenBank, indicating that Armenian geothermal Springs harbor novel bacilli, at least at the species level.
Abstract: In recent years, scientists have increasingly focused on the microbial diversity of high-altitude hot springs to explore the biotechnological applications of extremophiles. In this regard, a total of 107 thermophilic bacilli were isolated from 9 high-altitude mineralized geothermal springs (of temperatures ranging from 27.5 to 70 °C) located within the territory of Armenia and Nagorno-Karabakh. The isolated bacilli were phylogenetically profiled and studied for their potential to produce extracellular hydrolytic enzymes (protease, amylase, and lipase). The identification of isolates based on 16S rRNA gene sequences revealed their relationship to members of more than 22 distinct species, of 8 different genera, namely Aeribacillus, Anoxybacillus, Bacillus, Brevibacillus, Geobacillus, Parageobacillus, Paenibacillus and Ureibacillus. Bacillus licheniformis, Parageobacillus toebii and Anoxybacillus flavithermus were found to be the most abundant species in the springs that were studied. Some of the isolated bacilli shared less than 91–97% sequence identity with their closest match in GenBank, indicating that Armenian geothermal springs harbor novel bacilli, at least at the species level. 71% of the isolates actively produced at least one or more extracellular proteases, amylases, or lipases. In total, 22 strains (28.6%) were efficient producers of all three types of thermostable enzymes.

13 citations

References
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Journal ArticleDOI
TL;DR: Despite the extensive research on several aspects of proteases, there is a paucity of knowledge about the roles that govern the diverse specificity of these enzymes and deciphering these secrets would enable to exploit proteases for their applications in biotechnology.
Abstract: Proteases represent the class of enzymes which occupy a pivotal position with respect to their physiological roles as well as their commercial applications. They perform both degradative and synthetic functions. Since they are physiologically necessary for living organisms, proteases occur ubiquitously in a wide diversity of sources such as plants, animals, and microorganisms. Microbes are an attractive source of proteases owing to the limited space required for their cultivation and their ready susceptibility to genetic manipulation. Proteases are divided into exo- and endopeptidases based on their action at or away from the termini, respectively. They are also classified as serine proteases, aspartic proteases, cysteine proteases, and metalloproteases depending on the nature of the functional group at the active site. Proteases play a critical role in many physiological and pathophysiological processes. Based on their classification, four different types of catalytic mechanisms are operative. Proteases find extensive applications in the food and dairy industries. Alkaline proteases hold a great potential for application in the detergent and leather industries due to the increasing trend to develop environmentally friendly technologies. There is a renaissance of interest in using proteolytic enzymes as targets for developing therapeutic agents. Protease genes from several bacteria, fungi, and viruses have been cloned and sequenced with the prime aims of (i) overproduction of the enzyme by gene amplification, (ii) delineation of the role of the enzyme in pathogenecity, and (iii) alteration in enzyme properties to suit its commercial application. Protein engineering techniques have been exploited to obtain proteases which show unique specificity and/or enhanced stability at high temperature or pH or in the presence of detergents and to understand the structure-function relationships of the enzyme. Protein sequences of acidic, alkaline, and neutral proteases from diverse origins have been analyzed with the aim of studying their evolutionary relationships. Despite the extensive research on several aspects of proteases, there is a paucity of knowledge about the roles that govern the diverse specificity of these enzymes. Deciphering these secrets would enable us to exploit proteases for their applications in biotechnology.

2,159 citations

Journal ArticleDOI
TL;DR: The alpha/beta hydrolase fold as mentioned in this paper is common to several hydrolytic enzymes of widely differing phylogenetic origin and catalytic function, including the serine protease catalytic triad.
Abstract: We have identified a new protein fold--the alpha/beta hydrolase fold--that is common to several hydrolytic enzymes of widely differing phylogenetic origin and catalytic function. The core of each enzyme is similar: an alpha/beta sheet, not barrel, of eight beta-sheets connected by alpha-helices. These enzymes have diverged from a common ancestor so as to preserve the arrangement of the catalytic residues, not the binding site. They all have a catalytic triad, the elements of which are borne on loops which are the best-conserved structural features in the fold. Only the histidine in the nucleophile-histidine-acid catalytic triad is completely conserved, with the nucleophile and acid loops accommodating more than one type of amino acid. The unique topological and sequence arrangement of the triad residues produces a catalytic triad which is, in a sense, a mirror-image of the serine protease catalytic triad. There are now four groups of enzymes which contain catalytic triads and which are related by convergent evolution towards a stable, useful active site: the eukaryotic serine proteases, the cysteine proteases, subtilisins and the alpha/beta hydrolase fold enzymes.

1,891 citations

Journal ArticleDOI
TL;DR: In this article, the authors describe the physics that gives rise to the quantum limit to the Q-f product, explain design strategies for minimizing other dissipation sources, and present new results from several different resonators that approach the limit.
Abstract: Micromechanical resonators are promising replacements for quartz crystals for timing and frequency references owing to potential for compactness, integrability with CMOS fabrication processes, low cost, and low power consumption. To be used in high performance reference application, resonators should obtain a high quality factor. The limit of the quality factor achieved by a resonator is set by the material properties, geometry and operating condition. Some recent resonators properly designed for exploiting bulk-acoustic resonance have been demonstrated to operate close to the quantum mechanical limit for the quality factor and frequency product (Q-f). Here, we describe the physics that gives rise to the quantum limit to the Q-f product, explain design strategies for minimizing other dissipation sources, and present new results from several different resonators that approach the limit.

1,600 citations

Journal ArticleDOI
TL;DR: An updated and extensive classification of bacterial esterases and lipases is proposed based mainly on a comparison of their amino acid sequences and some fundamental biological properties, which results in the identification of eight different families with the largest being further divided into six subfamilies.
Abstract: Knowledge of bacterial lipolytic enzymes is increasing at a rapid and exciting rate. To obtain an overview of this industrially very important class of enzymes and their characteristics, we have collected and classified the information available from protein and nucleotide databases. Here we propose an updated and extensive classification of bacterial esterases and lipases based mainly on a comparison of their amino acid sequences and some fundamental biological properties. These new insights result in the identification of eight different families with the largest being further divided into six subfamilies. Moreover, the classification enables us to predict (1) important structural features such as residues forming the catalytic site or the presence of disulphide bonds, (2) types of secretion mechanism and requirement for lipase-specific foldases, and (3) the potential relationship to other enzyme families. This work will therefore contribute to a faster identification and to an easier characterization of novel bacterial lipolytic enzymes.

1,184 citations

Journal ArticleDOI
TL;DR: Scientific and technological developments and the future prospects for application of cellulases in different industries are discussed in this paper.
Abstract: Microbial cellulases have shown their potential application in various industries including pulp and paper, textile, laundry, biofuel production, food and feed industry, brewing, and agriculture. Due to the complexity of enzyme system and immense industrial potential, cellulases have been a potential candidate for research by both the academic and industrial research groups. Nowadays, significant attentions have been devoted to the current knowledge of cellulase production and the challenges in cellulase research especially in the direction of improving the process economics of various industries. Scientific and technological developments and the future prospects for application of cellulases in different industries are discussed in this paper.

768 citations