Thermophilic bacteria stearothermophilus

In industrial production, a lot of bacteria can be used for the production of CGTase, including aerobic mesophilic bacteria such as B. circulars and B. megaterium, etc, aerobic thermophilic bacteria such as B. stearothermophilus, and anaerobic thermophilic bacteria, such as Thermoanaerobacterium thermosul-furigenes, aerobic alkaliphilic bacteria such as B. circulars, Bacillus fat, and aerobic halophilic bacteria such as halophilic bacilli, etc. The CGTase secreted by most of the microbes are extracellular enzymes, and the yield of the CD and the main product of these enzymes are different, mainly a-CD, fi-CD and y-CD. 

FIGURE 25-8 Large (Klenow) fragment of DNA polymerase I. This polymerase is widely distributed in bacteria. The Klenow fragment, produced by proteolytic treatment of the polymerase, retains the polymerization and proofreading activities of the enzyme. The Klenow fragment shown here is from the thermophilic bacterium Bacillus stearothermophilus (PDB ID 3BDP). The active site for addition of nucleotides is deep in the crevice at the far end of the bound DNA. The dark blue strand is the template. 

The purpose of this review is to provide an overview of enzymes from extreme thermophiles with particular emphasis on thermostability characteristics, and with some reference to the commercial applicability of the enzymes. An extreme thermophile is defined here as an organism with a growth optimum of 65 °C or higher. This limits the scope of the review to bacteria, since no extremely thermophilic fungi or algae have been isolated, and excludes much of the work carried out on Bacillus stearothermophilus. 

Amylases classified in family 13 glycoside hydrolases have been described from the archaea to the bacteria domains. The genus Bacillus includes a set of species able to produce starch-d rading enzymes and has biotechnological potential as a source of these enzymes especially the a-amylases, which are the most fi equent starch-degrading enzymes described for bacteria. In addition. Bacillus a-amylases present activity and are stable in temperatures over 50-60 °C, therefore are very attractive for industrial applications. B. subtilis, Bacillus stearothermophilus. Bacillus lichenifortnis, and Bacillus atnyloliquefaciens have been widely used for commercial production of amylases and for the production of starch derivates. The a-amylases produced by other bacteria and also archaea have to compete with the Bacillus enzymes that already present excellent thermophilic properties and high conversion rates (Prakash and Jaiswal 2010). 

The hydantoinases hydrolyzing both d- and L-hydantoin were also found in several bacteria. They could be divided into two groups one needs ATP for its activity and the other does not. The ATP-requiring enzyme was purified and cloned from Pseudomonas sp. strain NS 671 [37,38]. The enzyme consists of two subunits with differing molecular mass of 76 and 65 kDa, and preferably hydrolyzes L-hydantoin. The enzyme that does not require ATP was purified and cloned from a moderate thermophilic bacterium B. stearothermophilus NS 1122A [39,40] and Arthrobacter sp. DSM 3745 [41]. The Bacillus enzyme is homotetrameric with molecular mass of 200 kDa. Although the monomer had no activity. 

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