| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 2075505 | Biocatalysis and Agricultural Biotechnology | 2014 | 9 Pages |
•Xylanase production by Bacillus altitudinis DHN8 using sorghum straw as an inducer.•Optimization of physiological and nutritional parameters under submerged condition.•Cellulase-free alkali-thermo-solvent-stable xylanase.•Effectiveness of alkaline hydrogen peroxide pretreatment.•Saccharification of sorghum straw biomass with crude xylanase.
A newly isolated Bacillus altitudinis DHN8 was assessed for xylanase production by utilizing sorghum straw. The highest xylanase production was recorded at sorghum straw 3% w/v, inoculum size 1% v/v, inoculum age 18 h, incubation time 42 h, pH 7.0, temperature 35 °C and agitation speed 250 rpm. Moreover, xylose 0.5%, gelatine 0.5% and KNO3 0.3% (w/v) further enhanced the production. The detailed optimization study resulted in a 3.74-fold increase in xylanase production as compared to that of the initial conditions. The partially purified xylanase showed ~70% pH stability after 18 h at pH range of 6–10. Thermostability study revealed more than 60% xylanase activity at temperature range 45–65 °C after 60 min. The presence of metal ions (10 mM CaCl2, MnCl2 and FeCl3) and solvents (10% v/v isopropanol, methanol, ethanol and acetone) were increased xylanase activities remarkably. During saccharification study, 3% alkaline hydrogen peroxide treatment was found to be beneficial for the maximum enzymatic hydrolysis of sorghum straw (34.94 mg/g reducing sugar) after 36 h. As such, this xylanase could be considered as a cellulase-free, thermo-alkali-solvent stable biocatalyst being important tool for many biotechnological industries.To the best of our knowledge, this is the first report on the production of xylanase by this Bacillus species.
