Transformation of
Aflatoxin B₁ and Zearalenone
using an evolved
high-redox potential laccase

Mycotoxins are the biggest challenge for animal feed producers and, therefore, regular monitoring and remediation is necessary.

Mycotoxins can be remediated by various methods, but enzymes and microbes for deactivating mycotoxins are becoming popular these days.

We have recently engineered a high-redox potential laccase by consensus design and DNA recombination to enhance its thermostability and substrate scope.

In the present study, we have tested the transformation of mycotoxins using the evolved laccase, DooKu variant.

1. INCUBATION

Deoxynivalenol (DON), Aflatoxin B₁ (AFB₁), Zearalenone (ZEN), T-2 toxin, Ochratoxin A (OTA) and Fumonisin B₁ (FB₁) (2 ppm) were incubated with 500 μl of DooKu enzyme Laccases) at 37°C; with syringaldehyde (10mM) as redox mediator for 1 hour.

2. QUANTIFICATION

After incubation, the samples were centrifuged and analysed by a LC-MS/MS based multi-mycotoxin method for quantification of all the mycotoxins (Aflatoxin B₁, Ochratoxin A, Zearalenone, Deoxynivalenol, FB₁ and T-2 toxin).

Different variants of Laccases were screened and Laccase 240 was among the best enzymes for transformation of AFB₁ and ZEN as shown in Table 1.

El siringaldehído demostró ser mejor cofactor en comparación con TEMPO.

The effect of pH was studied by carrying out assays at pH 3.0, 4.0, 5.0 and 6.5 pH.

⇰ Laccase 240 showed 73% transformation for AFB₁ at pH 6.5 and 99% transformation of ZEN at pH 5.0 as shown in Table 2.

Effect of incubation time was also studied as shown in Figure 1.

ZEN was transformed within 2 hours, whereas AFB₁ was transformed in 3 hours.