Fusarium venenatum is being extensively utilized for microbial protein production. However, its high dietary fiber content results in substantial carbon loss. Inhibition of chitin biosynthesis presents a promising strategy to improve the mycoprotein yield. Through transcriptomic and bioinformatics analyses, chitin synthase gene FvChs3 was identified as crucial for chitin synthesis in F. venenatum. Knockout of the FvChs3 gene resulted in mycelial expansion and a 26% reduction in the chitin content of strain ΔFvChs3. Ethanol production from fermentation decreased by 47%, while the carbon conversion efficiency and protein conversion increased by 16% and 36%, respectively. Transcriptomic analysis revealed an upregulation of nitrogen metabolism in ΔFvChs3, while genes related to the glycolysis pathway for ethanol synthesis were downregulated. Further knockout of pyruvate decarboxylase gene FvPDC6 in ΔFvChs3 accelerated growth, leading to improvements in carbon and protein conversion of 29% and 40%, respectively. This research lays the foundation for enhancing fungal protein production.
Keywords: CRISPR/Cas9; Fusarium venenatum; chitin; chitin synthase; mycoprotein.