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 °C, 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 °C with half-lives of 60 and 30 min at 45 and 50 °C, 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.