Production and optimization of cellulase-free, alkali-stable xylanase by Bacillus pumilus SV-85S in submerged fermentation

Abstract

This paper reports the production of a cellulase-free and alkali-stable xylanase in high titre from a newly isolated Bacillus pumilus SV-85S using cheap and easily available agro-residue wheat bran. Optimization of fermentation conditions enhanced the enzyme production to 2995.20 +/- 200.00 IU/ml, which was 9.91-fold higher than the activity under unoptimized basal medium (302.2 IU/ml). Statistical optimization using response-surface methodology was employed to obtain a cumulative effect of peptone, yeast extract, and potassium nitrate (KNO(3)) on enzyme production. A 2(3) central composite design best optimized the nitrogen source at the 0 level for peptone and yeast extract and at the -alpha level for KNO(3), along with 5.38-fold increase in xylanase activity. Addition of 0.1% tween 80 to the medium increased production by 1.5-fold. Optimum pH for xylanase was 6.0. The enzyme was 100% stable over the pH range from 5 to 11 for 1 h at 37 degrees C and it lost no activity, even after 3 h of incubation at pH 7, 8, and 9. Optimum temperature for the enzyme was 50 degrees C, but the enzyme displayed 78% residual activity even at 65 degrees C. The enzyme retained 50% activity after an incubation of 1 h at 60 degrees C. Characteristics of B. pumilus SV-85S xylanase, including its cellulase-free nature, stability in alkali over a long duration, along with high-level production, are particularly suited to the paper and pulp industry.

Endoglucanase and Xylanase Production by Chryseobacterium Species Isolated from Decaying Biomass

“…B. subtilis BS04 showed highest enzyme production at 35ºC. Higher incubation temperature also is 50-60ºC, which has been reported by other researchers in the literature [44][45][46][47][48][49].…”

Xylanase Production by Bacillus subtilis Using Carbon Source of Inexpensive Agricultural Wastes in Two Different Approaches of Submerged Fermentation (SmF) and Solid State Fermentation (SsF)

“…Thereby, we suggested the combination of yeast extract and peptone as the nitrogen source was anticipated to be the xylanase inducer for B. subtilis to produce more activity. This was supported by Nagar et al, [12] stated that organic nitrogen including yeast extract and peptone produced higher xylanase activity of 448.99 and 348.47 U/mL compared with inorganic compounds such as KNO 3 , (NH 4 ) 2 SO 4 and NaNO 3 . Additionally, Battan et al, [13] also reported that combination of yeast extract and peptone resulted in higher xylanase production.…”

Alkaliphilic bacteria: applications in industrial biotechnology

“…Various alkaliphilic bacteria have been shown to produce xylanase [6] with potential to remove color from paper mill effluents [19,58,171]. Other bacteria [20,178] showed production of xylanases that were adaptable to and stable at broad ranges of pH.…”