Toru Matsu-ura

　　Department of Molecular & Cellular Physiology, School of Medicine,

　　University of Cincinnati, Japan

　　Second-generation or cellulosic biofuel is a tangible source of renewable energy, which is critical to combat climate change by reducing carbon footprint. Filamentous fungi secrete cellulose-degrading enzymes called cellulases, which are required for the production of cellulosic biofuels. However, inefficient synthesis of cellulases is a major obstacle for industrial-scale production of second-generation biofuels. We used computational simulations to design and implement synthetic positive feedback loops to increase gene expression of a key transcription factor, CLR-2, that activates a large number of cellulases in a model filamentous fungus, Neurospora crassa . Our engineered Neurospora strains demonstrate simultaneous induction of approximately 50% of 78 lignocellulosic degradation-related genes. This results in dramatically increased cellulase activity due to cooperative orchestration of multiple genes involved in the cellulose degradation pathway. Our work provides a proof of principle in utilizing mathematical modeling and synthetic biology to improve the efficiency of cellulase synthesis for second-generation biofuel production.