266PURIFICATION OF XYLANASE FROM BACILLUS SUBTILIS BS166This objective of the study was to purify the xylanase produced by Bacillus subtilis by ammonium sulphate precipitation and with ion exchanger of DEAE –Sepharose and to determine the molecular weight of the purified xylanase. The spent medium contained 26.8 UmL-1xylanase activity and 1.51mgmL-1 protein. Highest specific activity (33.55Umg-1 protein) was precipitated with 50% (NH4)2SO4 saturation. The recovery of xylanase by (NH4)2SO4 precipitation was 95.03% showing specific activity of 33.16 Umg-1protein. The dialyzed enzyme was purified with DEAE-Sepharose and eluted with 0.8M NaCl. The specific activity of xylanase was increased from 32.14 to 212.5Umg-1 protein, which was 6.7 fold higher than that of the crude xylanase and the yield was 85%. When the purified xylanase was subjected to polyacrylamide gel electrophoresis, the sample gave a single band. The molecular weight of the purified xylanase is 66.42KDa. Thus the xylanase from Bacillus subtilis could be purified by precipitating with 50% saturation of ammonium sulphate and DEAESepharose ion exchange chromatography.ranganat@ualberta.caResearch572015Purification fold, DEAE-Sepharose,Specific activity,Elution,Dialyze,Bacillus subtilisRanganathan KapilanDepartment of Botany, Faculty of Science, University of Jaffna. Jaffna, Sri Lanka.