Biosynthesis of Industrially Relevant Extracellular Pectinase from Aspergillus terreus NCFT 4269.10 Using Orange Peels as Substrate

In this study, Aspergillus terreus NCFT4269.10 was selected for the biosynthesis of pectinase after screening from fifteen native fungal strains as the performance of A. terreus was best in pectin hydrolyzing activity (2.75 cm). Aiming at the cost effective fermentation, several agro-industrial residues such as, Pearl Millet (PM), Finger Millet (FM), Orange Peels (OP), Mustard oil Cake (MoC) and Chikling Vetch Peels (CVP) were evaluated for highest pectinase production using Liquid Static Surface Fermentation (LSSF) and Liquid Shaking Fermentation (LShF). Among these substrates, orange peel was found to be the most suitable substrate for optimal pectinase biosynthesis (LSSF: 633.33±57.73 U mLG1, LShF: 733.33±115.47 U mLG1). Liquid shaking fermentation at 120 rpm for 96 h at 30°C was suitable for pectinase biosynthesis as compared to LSSF. Total protein content was also higher in OP (LSSF: 880.33±12.5 μg mLG1, LShF: 992.7±4.16 μg mLG1) when the culture was grown under static and shaking condition at 30°C for 96 h. Maximum biomass was formed when OP was implemented for fermentation at static condition followed by CVP. But maximum biomass did not always support the enhanced pectinase biosynthesis in most of the cases. Partial purification of pectinase revealed a 3.86 fold purification and 27.63% yield of protein. Fermentation kinetics study revealed that purified enzyme activity yield per gram of substrate was maximum at both LSSF (1866.6 U gdsG1) and LShF (2026.7 U gdsG1) when biosynthesis of pectinase was carried out using OP. Ratio of enzyme yield and biomass were best with OP as compared to the other substrates both in static and shaking fermentation at crude and purified conditions.