Immobilization of an alkaline endopolygalacturonase purified from Bacillus paralicheniformis exhibits bioscouring of cotton fabrics

Pectin degrading enzyme has been increasing interest in an industrial application as biocatalysts, such as juice, textile, and wine industry. Bacillus paralicheniformis CBS3, isolated from popular traditional Korean food (kimchi), produced a novel extracellular thermostable alkaline endopolygalacturonase (BPN3). In this study, BPN3 was purified to 22.04-fold with a recovery yield of 18.93% and specific activity of 2216.41 U/mg by gel filtration and anion exchange column chromatography. The molecular mass of BPN3 was approximately 53 kDa as analyzed by SDS-PAGE and pectic zymography. The N-terminal sequence of BPN3 was AIPVILAX. BPN3 was stable over a broad pH range (8.14–11.47), was thermally stable at 50–60 °C, and functioned optimally in pH 9.1 at 60 °C. BPN3 had Km and Vmax values of 0.039 mg/mL and 747.9 ± 1.2 U mg− 1, respectively, whereas pectin from apple as substrate. BPN3 activity was remarkably affected by metal ions, modulators, and detergents. Digalacturonic acid (GA2) was the major oligosaccharide produced by hydrolysis of BPN3. Immobilized BPN3 was active over a pH range (8.1–11.5), temperature (50–60)°C, and remained stable with 63.34 and 43.41% of its relative activity during second and third cycle, respectively. Desized cotton exhibited highest reducing sugar liberation through optimized conditions of bioscouring. Bioscouring effectiveness of BPN3 was characterized by the comparison of weight loss for purified BPN3 with commercial pectinase and comparison of BPN3 with grey fabric. BPN3 was simple to purify, had high thermal stability, and was stable over a broad pH range that suggests its suitability for bioscouring application as an industrial catalyst.