Synthesis of Pectin Methylesterase from Aspergillus niger in Submerged Fermentation Using as Citrus Pectin and Orange Peel as Inducers

This work is a comparative study of the bioproduction of pectin methylesterase (PME) with medium composed of agro-industrial residues and synthetic medium using the filamentous fungus Aspergillus niger. After medium optimization, a kinetic evaluation was carried out, and the enzyme was characterized in terms of optimum pH and temperatures and stability at high and low temperatures. The maximum activity of PME in synthetic medium (42 g/L pectin, 1 g/L magnesium sulphate, and 10 g/L potassium phosphate) was 9.4 U/mL and in agro-industrial medium (120 g/L orange peel, 301.2 g/L corn steep liquor, and 600 g/L parboiled rice water) was 130 U/mL. These results were obtained in 56 and 124 h of bioproduction (180 rpm, 30°C, pHinitial 5.5, 5.106 spores/mL), respectively. Partial characterization of the crude extract of PME showed optimum pH and temperature of 11 and 55°C, respectively. Ed were 18 and 15 kJ/mol, with half-life times (t1/2 ) of 4,728 and 1,547 h for PME produced in synthetic and agro-industrial medium, respectively. Utilization of agro-industrial residues for enzymes production using submerged fermentation minimizes pollution and allows high added-value products to be obtained using economical technology.