Exploitation of Aspergillus niger for the Heterologous Production of Cellulases and Hemicellulases

Filamentous fungi of the Aspergillus niger group are native soil saprophytic fungi. Industrial strains of this group have been extensively used for the production of plant degrading enzymes for the food and beverage, animal feed and paper-and-pulp industries. Recombinant DNA technology allows for the overproduction of these enzymes in copious amounts. The advantages and limitations of A. niger as recombinant host for enzyme production are briefly discussed. Specific attention is devoted to the overproduction of several cellulases and hemicellulases to high homogeneity in the protease-deficient strain A. niger D15. The size, temperature and pH optima of the heterologous enzymes were shown to be similar to that of their natively produced counter parts. The optimization of enzyme production in dilute sugar cane molasses, using a recombinant strain producing the xylanase II of Trichoderma reesei as example, was also demonstrated.