Fungal biosynthesis of lignin-modifying enzymes from pulp wash and Luffa cylindrica for azo dye RB5 biodecolorization using modeling by response surface methodology and artificial neural network

Clara DouradoFernandes^a, Victor Ruan SilvaNascimento^a, Diego Batista Meneses^b, Débora S.Vilar^a, Nádia Hortense Torres^a,c, Manuela Souza Leite^a,c, José RobertoVega Baudrit^b,d, Muhammad Bilal^e, Hafiz M.N.Iqbal^f, Ram Naresh Bharagava^g, Silvia Maria Egues^a,c, Luiz Fernando Romanholo Ferreira^a,c

Graduate Program in Process Engineering, Tiradentes University, Murilo Dantas Avenue, 300, Farolândia, 49032-490, Aracaju, Sergipe, Brazil.

Abstract

This study demonstrates the evaluation between the artificial neural network technique coupled to the genetic algorithm (ANN-GA) and the response surface methodology (RSM) for prediction of Reactive Black 5 (RB5) decolorization by crude enzyme from Pleurotus. sajor-caju. Fungal lignin-modifying enzymes (FLME) were synthesized using pulp wash (PW) as an inducing substrate, and L. cylindrica (L.C) for cell immobilization. When grown in PW, the fungus showed higher Lac activity (126.5 IU. mL^-1), whereas when immobilized a higher MnP activity was achieved (22.79 IU. mL⁻¹), but both methods were capable of decolorizing the dye in about 89.4 % and 75 %, respectively. This indicates applicability of PW as an alternative substrate for FLME induction and viability of immobilization for MnP synthesis. For RB5 decolorization, the action of the crude enzyme extract was considered as a function of pH, dye concentration, temperature, and reaction time. The models are well adjusted to predict the efficiency of biodecolorization, with no statistical difference between ANN-GA and RSM, which indicates potential for green enzymes prospecting application in bioprocess industry.

Keywords: Reactive Black 5, Pleurotus sajor-caju, Immobilization, Genetic algorithm, Green enzymes.