Production, extraction, and quantification of laccase obtained from an optimized solid-state fermentation of corncob with white-rot fungi

Abstract

Laccase is an enzyme capable of biotransforming synthetic pollutants. Its production by four white-rot fungi Trametes pubescens, Phanaerochaete chrysosporium, Pleurotus ostreatus, and Pleurotus pulmonarius was evaluated during 7, 10, and 13 days under solid-state fermentation onto the agricultural by-product corncob. Pleurotus ostreatus was selected to optimize the fermentation conditions through a central composite design. It was found that laccase production is maximized using malt extract as carbon source (18.2 g L−1), yeast extract as nitrogen source fitting carbon-nitrogen ratio at 5.15:1, tween 80 as inducer (0.17% v v−1), and a moisture content of 85.0%. Subsequently, several factorial designs allowed to select 50 mM sodium acetate buffer pH = 6.0 and pH = 4.0 as the best conditions to extract and quantify the enzyme, respectively. The optimization of these three stages allowed a 4.6-fold increase in enzyme activity with respect to the value reached at the beginning of the research.