Filamentous fungi, such as Aspergillus niger and A. terreus, have been used commercially in medicine, agriculture, and the chemical industry. Aspergillus niger is the primary source of commercial citric acid production, and it can secrete an arsenal of enzymes that break down plant cell walls to free up sugars which can then be fermented and distilled into biofuel. Aspergillus terreus is a commercial production host for itaconic acid production. Meeting the demand for such products requires improving production. Pacific Northwest National Laboratory has developed methods to modify genetic components of the fungi to significantly enhance production.

Regulation of genes whose proteins control morphology and metabolism of filamentous fungi in manufacturing processes is critical to optimal product output. Current commercial fungal fermentation processes for citric acid, glucoamylase, microbial rennet, penicillin, and the statins produce tens to hundreds of grams per liter of product. Often the highest productivity is observed when the fungus exhibits a specific morphology. By identifying the genes responsible for regulating and maintaining optimal morphology and expression of enzymes and small molecule biosynthesis pathway, PNNL has engineered fungi capable of generating increased amounts of product.

The methods delete or enhance certain genes that alter fungal metabolism and/or morphology. The work factors in spore germination, filamentous growth, sporulation, and production of various products such as citric acid. Available are compositions such as fermentation broth and kits of the appropriate strains as well as methods of using the modified fungi.