Production and characterization of a thermo-pH stable pectinase from Bacillus licheniformis UNP-1: A novel strain isolated from Unapdev hot spring

Abstract

An efficient thermostable pectinase producer was isolated from the hot water spring of Unapdev and identified as <em>Bacillus licheniformis </em>UNP-1 using culture-dependent techniques by its morphological, microscopic, biochemical, physiological and molecular characteristics. Thermostable pectinase production was optimized in a submerged fermentation system using modified fermentation medium (MFM). The optimized components of MFM performed by changing one parameter at a time were pectinase defined liquid medium containing (g/L) 10 pure Pectin, 2.0 KH₂PO₄, 6.0 K₂HPO₄, 2.0 MgSO₄·7H₂O Optimized culture conditions were used for thermostable pectinase production. <em>Bacillus licheniformis </em>UNP-1 produced 55.2 U/mL of pectinase. Optimum pH and temperature for the production were 9 and 60 ^oC, respectively with 48 hours of incubation. The pectinase enzyme showed maximum activity at pH 11 and at 80^oC. Pectinolytic activity was the highest in the presence of Fe³⁺ metal ion. Optimum catalytic activity was recorded at substrate concentration of polygalacturonic acid of 3.5% after 90 min of incubation. The molecular mass of the dialyzed thermostable pectinase was 35 kDa. Partially purified pectinase enzyme was used for fruit juice extraction and clarification.