GHK-Cu Peptide Dramatically Boosts Laccase Enzyme Production in Fungus

Laccase is a versatile enzyme with significant applications in the food industry, bioremediation, and textile processing due to its ability to oxidize various substrates. Its industrial production often relies on fungal fermentation, which requires efficient and safe induction strategies to maximize yield. Current methods can involve toxic inducers or suboptimal efficiency, creating a need for novel, non-toxic approaches to enhance laccase synthesis that are suitable for sensitive applications like food processing.

The study found that after comprehensive medium optimization, GHK-Cu significantly enhanced laccase activity, achieving a remarkable 12.77-fold increase compared to control cultures grown without any inducer. This demonstrates its potent stimulatory effect on enzyme synthesis. The optimized strategy, leveraging GHK-Cu, resulted in a high laccase production of 1113.8 U L-1 when successfully scaled up in a 5-L stirring tank, unequivocally demonstrating its industrial potential and efficiency. Crucially, GHK-Cu consistently outperformed CuSO4 in inducing laccase production at the same molar concentration, indicating its superior efficacy and potentially safer profile. Mechanistically, GHK-Cu was shown to increase fungal cell membrane permeability with minimal cellular damage, thereby facilitating enhanced adsorption, intracellular accumulation, and more efficient utilization of copper ions, which are essential cofactors for laccase synthesis. This improved copper handling and bioavailability directly led to better expression of key laccase-related genes compared to induction with CuSO4, culminating in higher enzyme yields.