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The objective of the study was to optimize the culture medium and conditions for the production of
xylanase from Bacillus pumilis AB-1. Xylanase production was found to increase when wheat bran is
used as a lignocellulosic substrate at pH 5.0 and at 37oC temperature when moisture ratio was kept 1:01.
Further optimization was carried out using Plackett-Burman design and Central-Composite Design. The
Plackett-Burman multifactorial design was first employed to screen the important nutrient sources in the
medium for xylanase production by Bacillus pumilis AB-1 and subsequent use of the response surface
methodology (RSM) was further optimized for xylanase production by Central Composite Design. Wheat
bran, pH and Temperature showed greater value of the F-ratio then the F-table (F-ratio > 4.21001) and
exerted positive influence on the Xylanase production. The Central Composite Design predicts that the
xylanase production is located at the actual values of 1.86 gm% of wheat bran at pH 6.21. After the
statistical optimization 5.58 fold increase in the xylanase production was observed over unoptimized
medium.
Keywords: Bacillus pumilis AB-1; xylanase; Plackett-Burman design; Central Composite Design, lignocellulosic substrate.