Production, Partial Purification, and Characterization of Polygalacturonase from Aureobasidium pullulans P56 under Submerged Fermentation Using Agro-Industrial Wastes.

Abstract

Polygalacturonase (PGase) production by Aureobasidium pullulans P56 under submerged fermentation was investigated using agro-industrial wastes and commercial carbon and nitrogen sources. The maximum PGase concentration was equivalent to 8.6U/mL that was obtained in presence of citrus pectin at 150rpm, 30°C, pH = 5.5, and 60h of fermentation conditions. However, a significant amount of enzyme production was also recorded upon the utilization of corncob (5.3U/mL) and wheat bran (4.4U/mL) as carbon sources. Amongst the different nitrogen sources, the highest enzyme production (8.2U/mL) was obtained in presence of ammonium sulphate and yeast extract simultaneously at a ratio of 1:1. The enzyme was partially purified by gel filtration using Sephadex G50 equilibrated and washed with 50mM-sodium acetate buffer. The obtained yield and specific activity were determined equivalent to 17% and 9.53U/mg, respectively. The molecular weight of the partially purified enzyme was estimated as 54kDa on SDS-PAGE. The conditions affecting the enzyme activity were determined and the highest enzyme activity was recorded at 40°C and 4.5pH. Amongst the tested metal ions, 2 and 5mM of CaCl2 concentrations increased the enzymatic activity by 30%. Overall, the use of corncob (2.5%) to produce PGase by A. pullulans represents an attractive agro-industrial substrate.