Production of a high level of laccase by submerged fermentation at 120-L scale of Cerrena unicolor C-139 grown on wheat bran

Abstract

Submerged fermentation in a stirred bioreactor of the white rot fungus Cerrena unicolor C-139 was done at a 120-L scale in the presence of wheat bran as a cheap lignocellulosic substrate for fungus growth and laccase production. Enzyme monitoring showed that laccase production started after 2 days of cultivation, attaining a maximum activity of 416.4 U·mL(-1) at day 12 of fermentation. After treatment of culture liquid by successive micro- and ultrafiltration (5kDa), a liquid concentrate containing 22203176 units of laccase was obtained. Obtaining large amount of laccase is essential for various industrial applications, including detoxification of industrial effluents, textile and petrochemical industries, polymer synthesis, bioremediation of contaminated area, stabilization of beverages, production of cosmetics, manufacture of anti-cancer drugs, and nanobiotechnology. The cultivation method and the fungal strain used here provided a substantial amount of enzyme produced at a price lower than 0.01 € cent/unit enzyme.

Keywords: Cerrena unicolor; Laccase; Scaling-up submerged fermentation; Wheat bran.