In recent years interest in new xylanolytic enzymes from microbial sources has grown due their numerous applications in different industrial sectors [1]. Hemicellulases are typically produced as a mixture of different hydrolytic enzymes. which act on xylan, degrading its backbone into small oligomers. Among these, the best known are endo-xylanases (endo-1,4-ß-D-xylan xylanohydrolase; EC 3.2.1.8.). Xylanases are typically purified using two or more chromatographic steps [2]. These protocols often involve a precipitation step, followed by an ion exchange and/or gel filtration. Another approach is based on molecular biology tools, which involves cloning the codifying gene (s) in order to produce the recombinant enzymes in an adequate expression vector.

In this work a simple method involving electroelution for the purification of an active xylanase with a high molecular weight, excreted by a strain of Bacillus subtilis, is described [3]. Although electroelution is a well described method, it usually requires appropriate apparatus.Furthermore, this approach has not been previously reported for xylanase purification.

This method is efficient and reproducible enough to be used as a routine method for eluting multiple protein bands, allowing considerable time saving. It is simple, fast, cost-effective and does not require prior knowledge of the protein characteristics.

[1] Duarte, J.C., Costa-Ferreira, M. FEMS Microbiol. Rev., 13, 377-386, 1994.

[2] Ratanakhanokchai, K., Kyu, K.L., Tanticharoen, M. Appl. Environ. Microbiol., 65(2), 694-697,1999.

[3] Sá-Pereira, P., Duarte, J.C., Costa-Ferreira, M. Enzyme Microb. Technol.. (in press).