Biotechnological potential of agro-industrial waste in the synthesis of pectin lyase from Aspergillus brasiliensis

Abstract

This study aims at investigating pectin lyase bioproduction in submerged fermentation with synthetic medium and agro-industrial residues, using the filamentous fungus Aspergillus brasiliensis. The maximum pectin lyase activity in a synthetic medium (42 g/l pectin, 40 g/l yeast extract, and 0.02 g/l iron sulfate) was 31 U/ml, and 46 U/ml in the agro-industrial medium (160 g/l orange peel, 150 g/l corn steep liquor, and 300 g/l parboiled rice water), obtained over 60 and 124 h of bioproduction, 180 r/min, 30 ℃, pH_initial 5.5, and 5·10⁶ spores/ml, respectively. Partial characterization of pectin lyase crude enzyme extract obtained from the synthetic medium and the one made of agro-industrial residues showed optimum conditions at pH of 5.5 and 4.5 and temperatures of 37 and 55 ℃, respectively. The E_d obtained was 3.13 and 9.15 kJ/mol, and the half-life time (t_1/2) was 5.71 and 80 h at 55 ℃ for pectin lyase produced in synthetic and agro-industrial medium, respectively.