Exoenzymes

4 Key excerpts on "Exoenzymes"

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  eBook - ePub

  Biotechnological Applications of Extremophilic Microorganisms

  • Natuschka M. Lee(Author)
  • 2020(Publication Date)
  • De Gruyter

    (Publisher)

  4  Extremozymes: from discovery to novel bio-products

  Giannina Espina

  Paulina Cáceres-Moreno

  Daniela Correa-Llantén

  Felipe Sarmiento

  Jenny M. Blamey

  4.1  Abstract

  Biocatalysis has proven to be an essential industrial tool for converting raw material into valuable bio-products. The discovery of new enzymes, the improvement of enzymatic features, and the development of new processes for enzyme production will drive future innovation.

  For the chemical industry, the use of enzymes presents important benefits, which include higher selectivity, increased sustainability, and a low toxicity. These benefits are translated in cleaner production processes and lower environmental impact.

  Enzymes derived from extremophiles, or extremozymes, often have extraordinary properties, which include being able to carry out reactions at nonstandard conditions (e.g. high or low temperatures, acidic or alkaline pH, high concentrations of salt or organic solvents, and high pressure) where other enzymes underperform.

  Working with extremophiles and their native extremozymes is difficult due to the culture conditions required; they have usually low cell yield and low enzyme expression. For these reasons, to achieve industrial production levels, available extremozymes have been overexpressed in suitable heterologous host-vector systems.

  In this review, we present a road map to find enzymes from extremophiles. We will explore the process from discovering an enzymatic activity in a microbial crude extract through the application of a functional biochemical approach, up to the development of a new enzymatic product.

  4.2  Biocatalysis benefits and barriers

  Enzymes are biocatalysts that improve the rate of biochemical reactions by lowering their required activation energy. A reaction that would normally take a long time, such as oxidation, can occur in just milliseconds if the appropriate enzyme is used. Due to the high selectivity of enzymes, it is possible to optimize chemical reactions in different manners: maximizing the use of energy, minimizing the generation of secondary products, and reducing the reaction time. Thanks to the commercial, technical, and environmental benefits that the use of enzymes offers, biocatalysis is increasingly gaining interest for application in several industrial processes.

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  eBook - PDF

  Applied Biotechnology and Microbiology

  • Smith, P(Authors)
  • 2018(Publication Date)
  • Agri Horti Press

    (Publisher)

  Enzymes are also energized protein molecules found in every living cell, and are necessary for life. There are over 2000 known enzymes, each of which is involved with one specific chemical reaction. They are any of various proteins, originating from living cells and capable of producing certain chemical changes in organic substances by catalytic action, such as digestion. These proteins, and their function (s), are determined by their shape. In cells and organisms, most reactions are catalyzed by enzymes, which are regenerated during the course of a reaction. Biological catalysts are physiologically important because they speed up rates of reactions that would otherwise be too slow to support life. Our bodies naturally produce digestive and metabolic enzymes as they are needed. Specifically, the pancreas produces enzymes that break down foods into nutrients the body can use for energy and other bodily functions. The names of enzymes often include the substrate or substance on which they act, joined with an-ase ending. For example, lactase acts upon lactose and maltase acts on maltose to produce glucose. Sometimes they are named for their reaction product, for example, sucrase is often called invertase, because invertase is the result of the reaction of sucrose. Enzymes can also bear a name the describes the reaction that is catalyzed. An example of this includes the use of the name oxidase, because oxidase is involved in an oxidation reaction. Two types of enzymes • Simple enzymes are those composed completely of proteins • Complex enzymes are those composed of protein and a small organic molecule (s) (also known as holoenzymes) Enzymes are Categorized by their Function (s) : • Metabolic enzymes catalyze and regulate every biochemical reaction that occurs in your body and are essential to cellular function and health.

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  Medical Biochemistry

  • Gustavo Blanco, Antonio Blanco(Authors)
  • 2017(Publication Date)
  • Academic Press

    (Publisher)

  Countless chemical reactions take place at a given time in every living being. Many of them transform exogenous substances, which come with the diet, to obtain energy and the basic materials that will be used for the synthesis of endogenous molecules.

  Biochemical transformations are performed at a remarkable fast rate and with great efficiency. To reproduce them in the laboratory, these reactions would need extreme changes in temperature, pH, or pressure to take place; these changes are not compatible with cell survival. Under normal physiological conditions (37°C for warm-blooded organisms, pH near neutrality, and constant pressure), most of the reactions would proceed very slowly or may not occur at all. It is the presence of catalysts that allow chemical reactions in living beings to occur with great speed and under the mild conditions that are compatible with life.

  Enzymes are biological catalysts

  A catalyst is an agent capable of accelerating a chemical reaction without being part of the final products or being consumed in the process. In biological media, macromolecules called enzymes act as catalysts.

  As any catalyst, enzymes work by lowering the reaction activation energy (A e ) (see p. 152). Enzymes are more effective than most inorganic catalysts; moreover, enzymes show a greater specificity of effect. Usually inorganic catalysts function by accelerating a variety of chemical reactions, whereas enzymes catalyze only a specific chemical reaction. Some enzymes act on different substances, but generally, these are compounds with similar structural characteristics and the catalyzed reaction is always of the same type.

  The substances that are modified by enzymes are called substrates .

  The specificity of enzymes allows them to have high selectivity to distinguish among different substances and even between optical isomers of a compound. For example, glucokinase, an enzyme that catalyzes d -glucose phosphorylation, does not act on l

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  Applied Process Thought

  Initial Explorations in Theory and Research

  • Mark Dibben, Thomas Kelly, Mark Dibben, Thomas Kelly(Authors)
  • 2013(Publication Date)
  • De Gruyter

    (Publisher)

  X. Enzymes as Ecosystems: A Panexperientialist Account of Biocatalytic Chemical Transformations Ross L. Stein All life processes are chemical processes. A living cell reflects an intricate choreography of thousands of chemical reactions that convert molecular food-stuffs into energy to maintain homeostasis and to drive cell division. All of these reactions require catalysis, or acceleration, if they are going to occur with sufficient rapidity to sustain life. And it is these catalytic tasks for which enzymes have evolved. Enzymes are highly specialized protein molecules that have the ability to accelerate the rates of essential biochemical reactions by factors that generally exceed a billion and can be as large as 10 20 . 1 As an example of an important biochemical reaction that is subject to catalysis, consider protein degradation. Proteins are long polymers of amino acids and, as an essential part of the normal physiology of every cell, are broken-down to their constituent amino acids by a chemical reaction known as ‘hydrolysis’. One of the features of proteins is their exceptional stability. It has been estimated that the half-life for protein hydrolysis is on the order of 100 years 2 . So, left to its own devices, a protein would remain largely intact for centuries. Such sluggish reaction rates are clearly incompatible with life processes. Fortunately, nature has provided a class of enzyme (i.e., ‘proteases’) that is able to accelerate the degradation of proteins by factors that approach a billion. Instead of taking hundreds of years, a protein can be degraded by a protease in less than a second. The natural question to ask here, and what remains the central question in contemporary enzymology, is how enzymes are able to bring about such large rate accelerations? Much progress has been made in recent years. It is known that enzymes, like all proteins, do not exist in solution as rigidly stretched-out and linear rod-like structures.

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