Scale up of Cerrena unicolor Laccase Production

Abstract

The effect of different carbon source in culture medium of wood–degrading basidiomycete Cerrena unicolor C–139 were investigated. The maximal growth and laccase synthesis in shaken flask was observed in mineral salts broth containing maltose as the carbon source and asparagine as the nitrogen source (C/N=17.45). The maximal laccase activities in this condition (in the end of fungus expotential growth phase) was 4–times higher (28000 nkat/l) according to control conditions with glucose. The comparison of different inoculum age preparations for laboratory scale fermentor seeding display that the best results (154 078 nkat/l) were observed when the mycelium comes from the early expotential growth phase. In the scale–up process in SIP type 40l fermentor controlled automatically by the cascade of agitation (200–500 rpm) and gas flow of air (2–3 SLMP) giving the dissolved oxygen concentration in the range of 35–100% of initial amount, (enriched from 2 to 6 day of cultivation by the sequential addition of 10 μM cupric ions) the highest laccase activity in the medium with glucose (150,000 nkat/l) or maltose (145,000 nkat/l) at 8–th and 10–th day of cultivation were observed. The after culture fluids from these time were next concentrated and partially purified giving the crude laccase preparations Lac–G and Lac–M (from media with glucose or maltose respectively). The obtained preparations compared by ion–exchange HPLC, electrophorese and cyclic voltammetry gave no significant differences in their properties

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