Abstract

This paper reports the enhanced production of extracellular thermostable feruloyl esterase and xylanase from Bacillus pumilus by optimization of inducing carbon sources. Batch studies were evaluated by varying the ratio of xylan and wheat bran on the medium for enzyme production by the bacterial culture. The feruloyl esterase and xylanase production were highest in culture filtrates from B. pumilus grown in media containing 1% xylan and 3% wheat bran, which were enhanced 2.4-fold and 3.6-fold compare to single xylan medium, respectively. The crude feruloyl esterase and xylanase were thermostable with the maximum activities at 50 and 55°C, and pH 5.8 and 7.4, respectively. Activity at temperatures of 40 to 45°C was high and stable,suggesting that these enzymes have a potential application in obtaining ferulic acid from agro-industrial waste materials in this moderate temperature range.

Key words: Bacillus pumilus, feruloyl esterase, xylanase, production, partial characterization.