Abstract: The present invention provides a new fungal production system comprising a fungal host strain of Chrysosporium lucknowense wherein the endogenous cellulase secretion is less than 20% of the endogenous cellulase secretion of Chrysosporium lucknowense strain UV 18-25. Preferably, also the secretion of endogenous protease, endogenous ?-glucanase and endogenous cellobiohydrolase is less than 20% of the secretion of Chrysosporium lucknowense strain UV 18-25. Furthermore, fungal host strains are provided wherein several genes have been disrupted. According to another aspect of the invention a method for homologous and/or heterologous production of a pure protein with a purity of higher than 75%, comprising expressing a gene encoding said protein in the strains according to the invention have been described. Furthermore, a method for production of artificial protein mixes comprising expressing a gene encoding each of said proteins in a strain according to the invention have been disclosed.