Biotechnological Applications of Thermus thermophilus as Host

Aurelio      Hidalgo; José      Berenguer

doi:10.2174/18722083113076660030

Abstract

Thermostability is a desired property for the biotechnological use of enzymes as it increases the half-life of the enzyme, facilitates its transport and conservation, and is associated to additional resistance against the action of detergents and organic solvents. The availability of thermostable enzymes depends either on the discovery of the appropriate enzyme from a thermophilic microorganism or in the isolation of thermostable variants of a thermo-sensitive enzyme that catalyzes the desired reaction. In the first case the overproduction of the enzyme is attempted in well-known mesophilic hosts. As only low percentage of the genes encoded by thermophiles can be expressed in such hosts, the development of appropriate thermophilic hosts is required. Among extreme thermophilic bacteria, a complete genetic toolbox has been developed only for Thermus thermophilus, in such a way that this organism can be used as cell factory for the recombinant production of thermophilic proteins at their natural temperatures. Plasmids, thermostable resistances to antibiotics, reporters, and available promoters are reviewed that can be used for protein expression at high temperatures. Tools developed for the direct selection of thermostable variants of mesophilic proteins by protein folding interference in T. thermophilus are also described.

Keywords: Expression vectors, selection markers, thermophiles, thermoselection, thermostability thermozymes.

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