Simultaneous production of industrially important alkaline xylanase-pectinase enzymes by a bacterium at low cost under solid-state fermentation conditions

摘要

Simultaneous production of alkaline xylanase and all seven types of pectinases by a bacterial isolate, under solid-state fermentation was checked in this study. Under optimized conditions, high concurrent production of xylanase (22,800 +/- 578 IU/g substrate) and pectinase (4,832 +/- 189 IU/g substrate) was achieved. The different types of pectinases produced were exo-polymethylgalacturonase (782 IU/g), endo-polymethylgalacturonase (6.42 U/g), exo-polygalacturonase (2,250 IU/g), endo-polygalacturonase (11.57 U/g), polymethylgalacturonate lyase (53.99 IU/g), polygalacturonate lyase (59.78 IU/g), and pectin esterase (5.78 IU/g). Wheat bran resulted in the highest titer of both enzymes. The maximum xylanase-pectinase yield was detected after 7 days of incubation with 2 mM MgSO4 and 1.5 g/L K2HPO4 at wheat bran to moisture ratio 1:1.5 (w/v), media to flask volume ratio 1:25, pH 7.0, temperature 37 degrees C, and inoculum size 15%. Xylanase was most stable at pH 8.0, retained more than 75% activity up to 24 H, whereas pectinase was most stable at pH 9.0, having full activity even after 24 H. At 45 degrees C, the xylanase showed 82% residual activity after 6 H of incubation. The pectinase was 97% and 61% stable up to 3 H at 50 and 55 degrees C, respectively. This is the first report showing the production of xylanase-pectinases by bacterium along with high titer of seven types of pectinases, suitable for industries.