Fig. 6

Schematic diagrams for producing cellulosic ethanol by genetic engineering of filamentous fungi T. reesei PC-3-7-A723. The truncated type ACE3-723 is transformed into T. reesei PC-3-7 to generate the engineered cellulase hyper-producer PC-3-7-A723. The truncated ACE3-723 induces cellulase expression by interacting with XYR1. PC-3-7-A723 inherits the classical mutation sites in CRE1 (releasing CCR to enhance cellulase gene expression) [22], BGLR (decreasing β-glucosidase gene expression and increasing cellulase gene expression) [24], and BGL2 (promoting the conversion of cellobiose to sophorose to induce cellulase gene expression) [13] from PC–3–7, which contribute to the improvements of cellulase. We integrated these crucial mutations in PC-3-7-A723 by rational engineering to promote the cellulase production for cellulosic ethanol