Efficient Production of the Recombinant Human Lactoferrin in an Engineered <i>Trichoderma reesei</i>

Recombinant human lactoferrin (rhLF) was efficiently produced in Trichoderma reesei ( T. reesei ). An efficient and cost-effective Indirect ELISA was developed for detection. Using microcrystalline cellulose, the rhLF titer reached 184.76 mg/L. Overexpressing pdi1 increased rhLF titer 1.25-fold, and deleting pea1 enhanced it 1.30-fold. Combining these modifications in T. reesei CJ2095 Δ pea1:: pdi1 achieved 306.31 mg/L. Further optimization with 1% bran and 1.5 g/L Tween-80 boosted the titer to 368.47 mg/L. Scaling up to a 5 L fermenter yielded 1349.5 mg/L, a 1.93 × 10 4 -fold improvement over initial levels. The purified rhLF exhibited a secondary structure and antibacterial activity comparable to those of commercial rice-expressed lactoferrin. To our knowledge, this is the first report demonstrating the efficient production of rhLF using T. reesei as an expression host. This study highlights the potential of T. reesei as a robust platform for the industrial-scale production of human lactoferrin.