الفهرس 
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Abstract
One of the main problems in most enzymatic industrial processes is how to achieve an appropriate compromise between harsh working conditions and enzyme stability.
Wide varieties of stable enzymes are available from extreme thermophiles. The need of extremophile enzymes is increased. Such enzymes have found their utility in bio-industries such as leather, food, animal feed, textiles, in bioconversions and bio-remediation. Furthermore, the variety of these organisms producing extremoenzymes found over a relatively short time is an indication that the resource has barely been tapped. Enzymes from extreme thermophiles are not only stable to heat, but also to organic solvents, detergents and chaotropic agents. This opens up the possibility of using enzymes in the presence of denaturing substrates or products, and in harsh conditions generally.
In this thesis, Screening of microorganisms producing enzymes from different areas of soil led to the isolation of 38 isolates, the isolates were plate-screened for their ability to produce extracellular enzymes.
The promising strains were selected and screened for their enzyme thermostability and screened quantitatively for the enzyme activity for potential industrial and therapeutic application.
Tolerance of selected microorganisms was investigated to a varied range of pH, salinity, and enzyme activity over a range of temperature. Genotypic identification of 16s rRNA sequence of the promising strains revealed that the isolated strains were Streptomyces mutabilis, Streptomyces ghanaensis, Streptomyces rochei and Enterobacter cloacae.
The isolated microorganisms quantified as an effective producer of industrially important enzymes amylase, cellulase, esterase, casienase and therapeutic enzyme (L-asparagginase).
The study shows that:
- All the five enzymes (caseinase, amylase, esterase, cellulase and L-asparaginase) produced from the four isolates still show enzyme activity (enzyme stability) at different high temperature (60oC, 80oC, 100oC).
- Four enzymes (caseinase, esterase, cellulase, L-asparaginase) produced from (Streptomyces rochei, Streptomyces ghanaensis, Enterobacter cloacae) show optimum activity at different high temperature (60 oC, 80 oC), while amylase produced from Streptomyces mutabilis show optimum activity at 37 oC.
- Streptomyces mutabilis produce acidophilic enzyme amylase, Streptomyces ghanaensis produce acidophilic enzyme cellulase and neutrophilic enzyme esterase, Enterobacter cloacae and Streptomyces rochei produce alkalophilic enzymes (L-asparaginase, caseinase) respectively.
- The four strains produce highest enzyme activity at high salt concentration (5 and 7.5%) (L-asparaginase, caseinase, cellulase, and amylase).
Extraordinary characteristics of such enzymes make them a promising and renewable tool for industrial biotechnological process. In the future, these extremozymes will be used in novel biocatalytic processes that are faster, more accurate, specific and environmentally friendly.