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|Title:||Paenibacillus campinasensis BL11 木聚醣酶及其變異株之大量表現、純化與熱穩定性探討|
Overexpression, purification and themostability of Paenibacillus campinasensis BL11 xylanase and its mutants
|Keyword:||Paenibacillus sp. BL11,xylanase X,xylanase H2,xylanase L2,聚乙二醇,|
Paenibacillus sp. BL11,xylanase X,xylanase H2,xylanase L2,PEG,
|Publication Year :||2011|
|Abstract:||在先前的研究中，從製漿漂前黑液（58oC，pH 9.83）中分離出可耐高溫高鹼的Paenibacillus sp. BL11。從該菌株分泌出的endo-1,4-xylanase 稱為xylanase X。兩株變異株（分別是胺基酸取代株xylanase H2(T44A)及後段缺失株xylanase L2（胺基酸序列270之後鹼基缺失）與xylanase X比較。Xylanase X的最佳反應條件為60oC、pH 7。在其最佳反應條件下，xylanase X具有2392 U/mg的酵素活性。Xylanase H2的最佳反應條件為55oC、pH 7。在其最佳反應條件下，xylanase H2具有9725 U/mg的酵素活性。Xylanase L2的最佳反應條件為50oC、pH 8。在其最佳反應條件下，xylanase L2具有4710 U/mg的酵素活性。將這些xylanase 做比較，在最佳反應條件下，xylanase H2 有效地增加其酵素活性。利用不同濃度的聚乙二醇（polyethylene glycol (PEG)）（最終濃度0 - 1.6%）保護xylanase X，在60oC、pH7條件下反應顯示最佳反應濃度為0.8%。Xylanase X, H2 以及L2 在50oC、PEG濃度為0.5%條件下反應160分鐘，酵素活性可以持續增加。而在55以及60oC反應條件下，xylanase X, H2 以及L2的酵素活性可以持續增加至反應80分鐘，但在反應160分鐘後，xylanase H2以及L2的酵素活性則降低。|
In previous research, a thermo-alkaline Paenibacillus sp. BL11 was isolated from black liquor (58oC, pH 9.83). The endo-1,4-xylanase secreted from this bacterium was designated xylanase X. Two mutants xylanase H2 (amino acid substitution mutant, T44A) and L2 (sequence deletion mutant after aa270) were compared with xylanase X. Optimum temperature and pH for purified xylanase X activity were 60oC and pH7. The xylanase X activity was 2392 U/mg under optimal condition. Those for purified xylanase H2 activity were 55oC and pH7. The xylanase H2 activity was 9725 U/mg under optimal condition and the activity was 8495 U/mg under 60oC and pH7. Those for purified xylanase L2 activity were 50oC and pH 8. The activity of xylanase L2 could arrive about 4710 U/mg at this condition. Comparing these xylanases, the activity of xylanase H2 was the only enzyme greatly improved by changing its assay condition. Using polyethylene glycol (PEG) to protected xylanase X in different concentration (0 - 1.6% of final volume) at 60oC and pH7 showed the optimal concentration of PEG was 0.8%. Protection of PEG 6000 at a final concentration of 0.5%, the activity of xylanase X, H2 and L2 could keep increase in 160 min at 50oC. At 55 and 60oC, the activity of xylanase X, H2 and L2 could keep increase in 80 min. But however the activity of xylanase H2 and L2 decreased after 80 min under this condition.
|Appears in Collections:||森林環境暨資源學系|
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