Wendy Yoder

Heterologous Expression and Protein Secretion in Filamentous Fungi

The first reports of transformation of filamentous fungi began appearing in the scientific literature in the 1960s and 1970s (e.g., Shamoian et al., 1961; Shockley and Tatum, 1962; Sen et al., 1969; Mishra and Tatum, 1973). However, no recombinant DNA methods were available at that time to confirm the integration of donor DNA, and it was only in 1979 that Case, Schweizer, Kushner, and Giles reported the transformation of Neurospora crassa with a plasmid vector. As a result of these and subsequent breakthroughs (including the expression of heterologous genes), a multi-million dollar per year industry has emerged, whose core technology is based on the expression and secretion of heterologous proteins by filamentous fungi. The industry supplies a diverse array of products with applications in a wide range of market sectors including detergents, food and beverages, textiles, starch, animal feed, personal care, pulp and paper, leather, fats and oils, and biocatalysis. In many cases these products are being used in manufacturing and industrial process development in lieu of harsh and toxic chemicals (Nedwin, 1997). In 2001, the world market for industrial enzymes was ∼1.6 billion US dollars (Novozymes, 2002), with products derived from filamentous fungi accounting for approximately 50% of this market.