Production, extraction and characterization of alkaline xylanase from Bacillus sp. PKD-9 with potential for poultry feed

Bacillus sp. PKD-9, isolated from the nest of mud dauber (Sceliphron caementarium) at CSIR-CFTRI, Mysore,
produced tremendous amount of xylanase [75,000 IU/g dried fermented wheat bran (IU/g DFWB)] after 72 h
under solid state fermentation using wheat bran as both carbon and nitrogen source at 37 1C, pH 8.0.
Optimization of operational conditions for xylanase extraction based on contour plots and variance analysis
using response surface methodology (RSM) further enhanced xylanase yield by 1.30-fold (98,0000 IU/g
DFWB). Biochemical characterization revealed that xylanase was optimally active at pH 8.0 and 50 1C with
half-lives of 60 and 30 min at 45 and 50 1C, respectively. It exhibited remarkable stability (more than 75.0%
activity) over a broad pH range (6.0–10.0) after 25 h of incubation at room temperature and even in the
presence of known inhibitors (iodoacetamide, iodoacetic acid and β-mercaptoethanol). The release of reducing
sugars from poultry feed after xylanase digestion suggested its potential in improving feed digestibility.