Novel alkali-thermostable xylanase from Thielaviopsis basicola (MTCC 1467): Purification and kinetic characterization

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• 作者：Baby Rani Goluguri^a ; Chiranjeevi Thulluri^a ; Uma Addepally^a ; ^{vedavathi1@jntuh.ac.in" class="auth_mail" title="E-mail the corresponding author} ; Prakasham Reddy Shetty^b
• 关键词：Rice straw ; Fermentation ; Alkali-thermostable ; Xylanase ; Purification ; Characterization
• 刊名：International Journal of Biological Macromolecules
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：82
• 期：Complete
• 页码：823-829
• 全文大小：1486 K

文摘

A novel extracellular alkali-thermostable xylanase was purified to an apparent homogeneity from the submerged fermented culture filtrate of Thielaviopsis basicola MTCC 1467, wherein, the fungus was fed with rice straw as prime carbon source. SDS-PAGE analysis of the xylanase showcased molecular weight of ∼32 kDa. This extracellular protein macromolecule had maximum xylanolytic activity at pH 5.5 and 60 °C, and was stable in the range of pH 5.0–10.0 for 5 days retaining >70% activity. The enzyme was stable at 30–50 °C for 5 h retaining >85% activity and further by retaining 70% activity at 60 °C for 2 h. The enzyme deactivation constants (k_d) were in range of 0.41–1.3. The kinetic experiments specified that the enzyme had K_m and V_max values of 1.447 ± 0.22 mg mL⁻¹ and 60.04 ± 1.25 IU mL⁻¹, respectively, for xylan. The purified xylanase was significantly inhibited by Cu²⁺ and Zn²⁺ (∼58%), whilst Ca²⁺ and Na⁺ ions displayed partial inhibition (<8%) Intriguingly, the K⁺ and Mn²⁺ ions enhanced the activity by about ∼10%. Both SDS and EDTA reduced its activity by ∼20%.