Tuesday, May 3, 2011
Xylanases have been interesting over the past two decades due to its great potential in industrial applications, such as in the food, feed, pulping and papermaking industries. Seventeen microorganisms, expected to be xylanolytic microorganisms were isolated from various environmental samples, such as soil, miscanthus residue, horse manure, compost, humus, etc. Among the strains, high xylanase activities strains were chosen and the xylanase genes were cloned from D1, D2, D4, E2, F8, G3 and G5 genomic DNA by polymerase chain reaction (PCR). The amplified PCR products were ligated with the T&A cloning vector system and the constructed plasmids were transformed into E. coli DH5α. The sequence analysis of the insert DNAs revealed the identification of a 640-bp region containing xylanase open reading frame. According to xylanase gene sequence analysis, D1 had gene sequence similarity of 99% with Bacillus subtilis MW10 endo-1,4-beta-xylanase (xylB) (DQ100307.1), and D2 and D4 had gene sequence similarity of 99% with Bacillus sp. NBL420 endo-xylanase gene (xylS) (AF441773.1). Moreover, E2, F8, G3 and G5 had gene sequence similarity of 99% with Bacillus subtilis xylanase gene (xyl) (AB457186.1).