Partial purification and characterization of L‐ arabinose isomerase produced from local isolate of Bacillus subtilis AH1

Fifteen of local isolates of Bacillus sp. Were obtained among forty isolates from different location of Iraqi soil . These isolate were subjected to primary and secondary screening and their ability for L-arabinose isomerase production were tested . The isolate A3 was the the highest in enzyme production with enzyme activity 30.53 unit / ml . The morphological and biochemical tests for isolate A3 revealed that this isolate belong to Bacillus subtilis and signed as AH1 . Crude enzyme of L-arabinose isomerase from Bacillus subtilis AH1 was produced under optimum condition by submerged culture and partially purified by two steps including , concentration with 60% saturation of ammonium sulfate and dialysis . The results revealed that the purification folds was 1.54 and yield were 24.20 % . The optimium pH for enzyme activity were 7.5 and the optimum pH of stability between 7-8 ,While the optimum temperature for enzyme activity was 50 oC and the optimum temperature for stability between 30 -50 oC for 30 min of incubation .