An alkali-tolerant xylanase produced by the newly isolated alkaliphilic Bacillus pumilus from paper mill effluent

作者：Wang, Jing; Zhang, Wei-wei; Liu, Jin-ni; Cao, Yao-ling; Bai, Xiao-ting; Gong, Yue-sheng^*; Cen, Pei-lin; Yang, Ming-ming

来源：Molecular Biology Reports, 2010, 37(7): 3297-3302.

DOI：10.1007/s11033-009-9915-6

• Alkali-tolerant xylanase
• Bacillus pumilus
• Expression
• Site-directed mutagenesis
• Thermostability

An alkaline active xylanase, XynBYG, was purified from an alkaliphilic Bacillus pumilus BYG, which was newly isolated from paper mill effluent. It had an optimum pH of 8.0-9.0, and showed good stability after incubated at pH 9.0 for 120 min. The optimum temperature for the activity was 50 degrees C, and the enzyme retained below 55% of its original activity for 30 min at 55 degrees C. The gene coding for XynBYG consists of 687 bp and encodes 229 amino acids. Similarity analysis indicated that XynBYG belong to family 11 glycosyl hydrolases. Site-directed mutagenesis was performed to replace five sites (Tyr/Ser) to Arg/Glu and the results demonstrated that the optimum temperature of the mutant Y7 (S39R-T146E) increased 5 degrees C and the half-life of inactivation (T1/2) at 60 and 65 degrees C was 1 h and 25 min, respectively. Thus, it provides a potential xylanase that can meet the harsh conditions in the industrial applications.

• 出版日期2010-10
• 单位浙江大学; 西北农林科技大学