Thermo-Alkali-Tolerant Recombinant Laccase from <i>Bacillus swezeyi</i> and Its Degradation Potential against Zearalenone and Aflatoxin B₁

Abstract

The enzymatic biodegradation of mycotoxins in food and feed has attracted the most interest in recent years. In this paper, the laccase gene from <i>Bacillus swezeyi</i> was cloned and expressed in <i>Escherichia coli</i> BL 21(D3). The sequence analysis indicated that the gene consisted of 1533 bp. The purified <i>B. swezeyi</i> laccase was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis -12% with an estimated molecular weight of 56.7 kDa. The enzyme is thermo-alkali-tolerant, displaying the optimal degradation of zearalenone (ZEN) and aflatoxin B₁ (AFB₁) at pH 8 and 9, with incubation temperatures of 55 and 50 °C, respectively, within 24 h. The degradation potentials of the 50 μg of the enzyme against ZEN (5.0 μg/mL) and AFB₁ (2.5 μg/mL) were 99.60 and 96.73%, respectively, within 24 h. To the best of our knowledge, this is the first study revealing the recombinant production of laccase from <i>B. swezeyi</i>, its biochemical properties, and potential use in ZEN and AFB₁ degradation in vitro and in vivo.