M.Sc. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: Xylan is the second most abundant polisaccaride in nature. Endoxylanases, responsible for hydrolysis of the xylan, are an enzyme group used commonly in industry which is used especially at paper and pulp industries. In specially, xylanases from thermophiles are expected to play a significant role in industrial processes, since they are thermostable and resistant to pH changes. In this study determining the thermal stable xylanase gene sequence of a thermophilic bacterium which is called Geobacillus sp. 71 by inverse PCR, cloning of this gene to an E. coli expression vector, its purification and characterization are realized. A 1224 bp endoxylanese gene coding from Geobacillus sp. 71 sequenced and cloned into pET20b+ vector. Vector encoding this gene was transformed into E.coli BL21, expressed and enzyme was purufied by MagneHisTM Protein Purification System and characterized. The Geo71 Endoxylanase enzyme showed optimal activity at 75 °C in pH 7,0. It was determined that the enzyme had a lower Km 0,425 mM for oat spelt xylan than most of the xylanases and Vmax of value 500 U/mg. Effects of metal ions and some chemicals on the enzyme was determined by the studies that were conducted with different concentrations. Hg2+ (10 mM) almost strongly inhibited the enzyme activity. On the basis of amino acid sequence similarities, this 47 kDa enzyme could be assigned to family 10 of the glycosyl hydrolase classification system. Purified enzyme catalyzed the hydrolysis of oat spelt, the level of xylobiose and xylotetraose was high along with xylotriose and some oligosaccharides analyzed on TLC.In the light of all data it has been suggested that the enzyme’s biocatalytic properties proved to be one of the important industrial enzymes. Key Words: Geobacillus sp., endoxylanase, thermostable | |||||||||||||||||||||