Enzyme thermophile

Chirazymes. These are commercially available enzymes e.g. lipases, esterases, that can be used for the preparation of a variety of optically active carboxylic acids, alcohols and amines. They can cause regio and stereospecific hydrolysis and do not require cofactors. Some can be used also for esterification or transesterification in neat organic solvents. The proteases, amidases and oxidases are obtained from bacteria or fungi, whereas esterases are from pig liver and thermophilic bacteria. For preparative work the enzymes are covalently bound to a carrier and do not therefore contaminate the reaction products. Chirazymes are available form Roche Molecular Biochemicals and are used without further purification. 

This key enzyme of the dissimilatory sulfate reduction was isolated from all Desulfovibrio strains studied until now 135), and from some sulfur oxidizing bacteria and thermophilic Archaea 136, 137). The enzymes isolated from sulfate-reducing bacteria contain two [4Fe-4S] clusters and a flavin group (FAD) as demonstrated by visible, EPR, and Mossbauer spectroscopies. With a total molecular mass ranging from 150 to 220 kDa, APS reductases have a subunit composition of the type 012)32 or 02)3. The subunit molecular mass is approximately 70 and 20 kDa for the a and )3 subunits, respectively. Amino-acid sequence data suggest that both iron-sulfur clusters are located in the (3 subunit... 

Stability of several enzymes like proteases from thermophilic micro-organisms can be increased in aqueous-organic biphasic systems. Owusu and Cowan [67] observed a strong positive correlation between bacterial growth temperature, the thermostability of free protein extracts, and enzyme stability in aqueous-organic biphasic systems (Table 1). Enzymes, like other cell components (membranes, DNA, (RNA ribosomes), are adapted to withstand the environmental conditions under which the organism demonstrates optimal growth. 

The enzyme BdsC from the thermophilic strain B. subtilis WU-S2B has also been isolated [150], This enzyme has a subunit MW of 45kDa and a native molecular mass of 200 kDa. It has a temperature optimum of 50°C and a pH optimum of 8.0. Its stability at this temperature was 80% after incubation for 30 min. This enzyme demonstrated inhibition characteristics similar to other DBT monooxygenases, indicating involvement of metal ions and cysteine/SH groups in catalytic activity. 

The thermophilic enzyme DszD from Paenibacillus All-2 has been cloned into E. coli and characterized [172], The sequence of this enzyme showed 30% similarity to the major flavin reductase of Vibrio fischeri. The optimum activity was reported to be at 45°C in resting cell cultures and 55°C in cell-free extracts. 

Kirimura, K. Harada, K. Iwasawa, H., et al., Identification and Functional Analysis of the Genes Encoding Dibenzothiophene-Desulfurizing Enzymes From Thermophilic Bacteria. Applied Microbiology and Biotechnology, 2004. 65(6) pp. 703-713. 

Ohshiro, T. Ishii, Y. Matsubara, T., et al., Dibenzothiophene Desulfurizing Enzymes From Moderately Thermophilic Bacterium Bacillus Subtilis WU-S2B Purification, Characterization and Overexpression. Journal of Bioscience and Bioengineering, 2005. 100(3) pp. 266-273. 

Ishii, Y. Konishi, 1 Suzuki, M., and Maruhashi, K., Cloning and Expression of the Gene Encoding the Thermophilic NAD(P)H-FMN Oxidoreductase Coupling With the Desulfurization Enzymes From Paenibacillus Sp All-2. Journal of Bio science and Bioengineering, 2000. 90(6) pp. 591-599. 

The first two patents [150,151] protect the biocatalytic system and its use in the form of whole cells or cell-free extracts or enzymes purified from the organisms. The other claimed organisms in the patent include the thermophilic culture Aneurinibacillus sp. IGTN4T (ATCC N° PTA-4581), P. stutzeri, Yokenella sp. and P. nitroreducens. The following text gives the details of the strain PTA-806, since the others have not been reported in much detail. 

Extremozymes, enzymes from thermophilic bacteria, have become important in synthetic chemistry. 

Dos Santos AB, Cervantes FJ, Yaya-Beas RE et al (2003) Effect of redox mediator AQDS on the decolourisation of a reactive azo dye containing triazine group in a thermophilic anaerobic EGSB reactor. Enzyme Microb Technol 33 942-951... 

H. Kuhl, J. Kruip, A. Seidler, A. Krieger-Liszkay, M. Bunker, D. Bald, J.A. Scheidig, M. Rogner (2000) Towards structural determination of the water-splitting enzyme. Purification, crystallization, and preliminary crystallographic studies of photosystem II from a thermophilic cyanobacterium. J. Biol. Chem., 275 20652-20659... 

The VAPOR enzymes are flavoenzymes and can be isolated from thermophilic bacilli. They are especially valuable because they allow the regeneration of all four forms of the pyridine nucleotides NADH, NAD+ NAD PH, NADP+ according to the following equations [55,61] ... 

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