Engineered S1v1-AsLac laccase significantly boosts aflatoxin B1 and zearalenone degradation in contaminated feed.

Mycotoxin contamination, particularly from Aflatoxin B1 (AFB1) and Zearalenone (ZEN), poses a severe threat to feed safety and animal health, leading to significant economic losses and potential human health risks through the food chain. Current detoxification methods often fall short in efficiency or safety. Fungal laccases offer a promising biological approach for mycotoxin degradation, but their widespread practical application is hindered by insufficient catalytic efficiency and poor thermostability under industrial conditions. This study addresses these limitations by engineering a more robust laccase.

Researchers employed protein fusion technology to engineer a novel laccase, S1v1-AsLac, derived from the native laccase (AsLac) of Aspergillus terreus HNGD-TM15. The study compared the catalytic activity and thermostability of S1v1-AsLac against the native AsLac. Degradation efficiency was assessed for aflatoxin B1 and zearalenone using in vitro assays. The engineered enzyme's half-life was measured at 60 °C, and its storage stability was evaluated. Finally, S1v1-AsLac was applied to contaminated corn flour and corn bran feed samples to determine its efficacy in a practical matrix.

The engineered fusion enzyme, S1v1-AsLac, demonstrated significantly enhanced performance compared to the native AsLac. S1v1-AsLac exhibited a 49% improvement in AFB1 degradation and an 81% enhancement in ZEN degradation. Furthermore, its thermostability was markedly improved, showing a 2.02-fold extension in half-life at 60 °C, alongside better overall storage stability. When applied to contaminated feed samples, S1v1-AsLac effectively reduced mycotoxin levels:

For corn flour, degradation rates were 66.05% for AFB1 and 79.60% for ZEN. For corn bran, the degradation rates were 62.61% for AFB1 and 69.43% for ZEN.