Integration of Fe-MOF-laccase-magnetic biochar: From Rational Designing of a biocatalyst to aflatoxin B1 decontamination of peanut oil.

Enzymatic degradation of aflatoxins in food commodities has gained significant attention. However, enzyme denaturation in organic media discourages their direct use in oils to remove aflatoxins. For that, enzymes are immobilized or encapsulated for improved stability and reusability under unfavorable conditions. We sandwiched the laccase between a carrier and an outer protective layer. We used spent-mushroom-substrate (SMS) derived porous magnetic biochar as the laccase carrier and coated it with an iron MOF to create a biocomposite, Fe-BTC@Lac@FB. The immobilized laccase demonstrated enhanced chemical, thermal, and storage stability and proficient reusability. Fe-BTC@Lac@FB exhibited 11 times enhanced aflatoxin B (AFB) degradation compared to free laccase (FL). In addition, thermally inactivated Fe-BTC@Lac@FB could adsorb 11.2 mg/g of AFB from peanut oil. Multi-aflatoxin removal also proved promising, while Fe-BTC@Lac@FB could retain >85 % of AFB removal efficacy after five reusability cycles. Fe-BTC@Lac@FB treatment did not affect peanut oil quality as indicated by different oil quality parameters and proved essentially non-cytotoxic. All these aspects helped recognize Fe-BTC@Lac@FB as an excellent laccase-carrying material with exceptionally higher stability, activity, and reusability.