Manganese peroxidase production in submerged cultures by free and immobilized mycelia of Nematoloma frowardii

The agaric basidiomycete Nematoloma frowardii has been suggested as a good alternative for production of the extracellular ligninolytic enzyme, manganese-dependent peroxidase (MnP). Some cultural and environmental factors influencing the enzymatic activity in shaken flasks and aerated fermenter cultures were evaluated to improve the yields of the process. A low nitrogen medium (1.36 mM N added as ammonium tartrate), containing 16 g/l glucose (C/N ratio = 65.3), 2 mM Mn2+ and inoculated with immobilized polyurethane foam mycelium, made it possible to obtain a MnP yield of 2304 nkat/l in 8 days. Under these operational conditions, the enzyme productivity in the immobilized cells of N. frowardii was 1.4 times higher than that obtained with the free fungus. In the procedure with the reusable immobilized mycelium (semi-continuous culture) as many as three subsequent 10 day batches could be fermented by using the same carrier with no loss of MnP activity.