Overexpression of a Novel Vacuolar Serine Protease-Encoding Gene (spt1) to Enhance Cellulase Production in Trichoderma Reesei

Trichoderma reesei is widely applied as the major industrial fungus for production of cellulases used conversion lignocellulosic biomass to biofuels and other biobased products. The protein secretion pathway vital cellulase secretion, but few reports are related role vacuole in production. Here, we identified a novel vacuolar serine protease gene spt1 investigated ability T. secrete by disrupting, complementing overexpressing gene. Amino acid sequence analysis Spt1 showed that it belongs subtilisin S8 family has conserved catalytic triples (Asp, His, Ser) protease. deletion did not lead decrease extracellular activity, observation mycelia with Spt1–eGFP fusion expression membrane dye FM4-64 staining confirmed was an intracellular located vacuoles reesei. However, significantly reduced spore while complementation recovered these traits those parental strain. When overexpressed using its native promoter introducing multiple copies, improved. Furthermore, strong promoter, Pcdna1, drive overexpression, found enhanced. Specifically, filter paper activity overexpression strain SOD-2 reached 1.36 U/mL, which 1.72 times higher than These findings demonstrated can be powerful target increasing reesei, suggests possible important provides new clues improving strains efficient