A thermostable alkaline active endo-β-1-4-xylanase from Bacillus halodurans S7: Purification and characterization |
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Authors: | Gashaw Mamo Rajni Hatti-Kaul Bo Mattiasson |
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Affiliation: | aDepartment of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-22100 Lund, Sweden |
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Abstract: | A thermostable, alkaline active xylanase was purified to homogeneity from the culture supernatant of an alkaliphilic Bacillus halodurans S7, which was isolated from a soda lake in the Ethiopian Rift Valley. The molecular weight and the pI of this enzyme were estimated to be around 43 kDa and 4.5, respectively. When assayed at 70 °C, it was optimally active at pH 9.0–9.5. The optimum temperature for the activity was 75 °C at pH 9 and 70 °C at pH 10. The enzyme was stable over a broad pH range and showed good thermal stability when incubated at 65 °C in pH 9 buffer. The enzyme activity was strongly inhibited by Mn2+. Partial inhibition was also observed in the presence of 5 mM Cu2+, Co2+ and EDTA. Inhibition by Hg2+ and dithiothreitol was insignificant. The enzyme was free from cellulase activity and degraded xylan in an endo-fashion. |
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Keywords: | Xylanase Alkaliphile Bacillus |
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