Agricultural residues as potential substrates for production of xylanase from alkali-thermotolerant bacterial isolate

Bijender Kumar Bajaj^, ,Yash Paul Khajuria,Vijay P. Singh

 

                                                                                                                       

Abstract

Xylanolytic Bacillus pumilus SS1 grew well at highly alkaline pH (9–11) and at moderately high temperature (25–55 °C) and successfully utilized wheat bran as the sole carbon source and produced considerable titer of xylanase. Maximum enzyme production occurred at medium pH 8 and at 45 °C. The enzyme purified (2.97-fold) with ammonium sulfate fractionation and carboxymethyl sephadex chromatography, showed molecular weight of 25 kDa, low K_m (2.7 mg/ml) and reasonably good V_max (36 μmol/mg/min). Enzyme showed maximum activity at pH 6–8, and at 40–50 °C. Enzyme was inhibited by HgCl₂, CoCl₂, MnSO₄, MgCl₂, phenylmethylsulphonylfluoride and CaCl₂, while FeCl₂ caused slight stimulation.

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Keywords

• Bacillus pumilus SS1; Fermentation; Purification; Wheat bran; Xylanase; Zymogram