Purification and properties of a xylanase produced by Bacillus circulans BL53 on solid-state cultivation

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• 作者：Jú ; lio X ; ro Heck ; Lu&#xed ; s Henrique de Barros Soares ; Plinho Francisco Hertz ; Marco Antô ; nio Z&#xe1 ; chia Ayub
• 关键词：Xylanase ; Hemicellulose ; Solid-state cultivation ; Bacillus circulans
• 刊名：Biochemical Engineering Journal
• 出版年：2006
• 期刊代码：9_1369703x
• 类别：ce
• 出版时间：1 December 2006
• 卷：32
• 期：3
• 页码：179-184
• 文件大小：283 K

摘要

Xylanase from Amazon isolate Bacillus circulans BL53 grown on solid-state cultivation was purified to apparent homogeneity by ammonium sulphate fractioning, cation-exchange and gel filtration chromatography. A purification factor of 428-fold was achieved, with the purified enzyme presenting a specific activity of about 37 U mg⁻¹ protein. The xylanase molecular weight was calculated as 38 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and its isoeletric point was determined as 8.8. Determination of pH and temperature for the maximum activity was obtained using a 2² factorial design over an extensive range of pH (5.0–8.0) and temperatures (40–80 °C). The enzyme follows Michaelis–Menten kinetics with K_M and V_max values of 9.9 mg xylan mL⁻¹ and 25.25 μmol min⁻¹, respectively. The purified enzyme hydrolyzes soybean hull, soybean fiber, rice straw, grape skin and sugar cane bagasse. Its activity was stimulated by Co²⁺, Mn²⁺ and protein disulphide reducing reagents, but strongly inhibited by Hg²⁺ ions and SDS.