The global prevalence of aflatoxin B1 (AFB1) and zearalenone (ZEN) contamination in food and feed poses a serious health risk to humans and animals. Recently, enzymatic detoxification has received increasing attention, yet most enzymes are limited to degrading only one type of mycotoxin, and free enzymes often exhibit reduced stability and activity, limiting their practicality in real-world applications. In this study, the laccase CotA gene from ZEN/AFB1-degrading Bacillus subtilis ZJ-2019-1 was cloned and successfully expressed in Escherichia coli BL21, achieving a protein yield of 7.0 mg/g. The recombinant CotA (rCotA) completely degraded AFB1 and ZEN, with optimal activity at 70 °C and pH 7.0. After rCotA treatment, neither AFB1 nor ZEN showed significantly cytotoxicity to mouse macrophage cell lines. Additionally, the AFB1/ZEN degradation efficiency of rCotA was significantly enhanced by five natural redox mediators: acetosyringone, syringaldehyde, vanillin, matrine, and sophoridin. Among them, the acetosyringone-rCotA was the most effective mediator system, which could completely degrade 10 μg of AFB1 and ZEN within 1 h. Furthermore, the chitosan-immobilized rCotA system exhibited higher degradation activity than free rCotA. The immobilized rCotA degraded 27.95% of ZEN and 41.37% of AFB1 in contaminated maize meal within 12 h, and it still maintained more than 40% activity after 12 reuse cycles. These results suggest that media-assisted or immobilized enzyme systems not only boost degradation efficiency but also demonstrate remarkable reusability, offering promising strategies to enhance the degradation efficiency of rCotA for mycotoxin detoxification.

The co-occurrence of aflatoxin B1 (AFB1) and zearalenone (ZEN) in grain-based food and animal feed poses significant health risks to humans and animals due to their potent mutagenic, cytotoxic, and carcinogenic properties. Conventional physical and chemical methods are insufficient for effectively detoxifying multiple mycotoxins present in food and feed. In this study, we evaluated the capability of Bacillus subtilis ZJ-2019-1 (B. subtilis ZJ-2019-1) to simultaneously degrade AFB1 and ZEN while optimizing reaction to enhance degradation efficiency. The localization of active ingredients from B. subtilis ZJ-2019-1 was determined using high-performance liquid chromatography (HPLC). Our findings demonstrated that B. subtilis ZJ-2019-1 eliminated 60.88% of AFB1 and 33.18% of ZEN within 72 h at a concentration of 10 mg/L at 37 °C (pH 7.0) and exerted greater activity under alkaline conditions. The autoclaved and boiled supernatants of B. subtilis ZJ-2019-1 exhibited significant enhancement in the degradation of AFB1 and ZEN, achieving degradation rates of 79.85% and 100%, respectively, at a concentration of 1 mg/L within 48 h at 37 °C. Moreover, the crude enzymes from B. subtilis ZJ-2019-1 showed maximum degradation rates for AFB1 (100%) and ZEN (94.29%) within 72 h at 70 °C. Additionally, divalent cations (such as Co²⁺, Fe²⁺, Mn²⁺, and Ni²⁺) significantly augmented the activity of crude enzymes from B. subtilis ZJ-2019-1 towards mycotoxin degradation. Furthermore, when applied to corn gluten meals, B. subtilis ZJ-2019-1 strain effectively detoxify 66.08% of AFB1 and 22.01% of ZEN, surpassing the efficacy of a commercial detoxification agent on the market (34.17% for AFB1 and 2.28% for ZEN). Collectively, these findings indicated that B. subtilis ZJ-2019-1 is a promising candidate for the simultaneous removal of multiple mycotoxins in food and feed, while addressing health concerns associated with harmful mycotoxins.

Pathogenic Escherichia coli cannot be killed by most antibiotics (including colistin, a last-resort drug) due to the rapid development of antibiotic resistance. A highly conserved prokaryotic mitotic protein, filamenting temperature-sensitive protein Z (FtsZ) with GTPase activity, plays a key role in cell division and has become a promising target for screening novel antibacterial agents. In this study, the amplified ftsZ gene was inserted into cloning/expression vectors and recombinantly produced in E. coli; the recombinant FtsZ protein was purified by the Ni²⁺-NTA affinity column and then was used to screen for natural antibacterial agents. The results showed that the ftsZ gene with a size of 1170 bp was successfully amplified from E. coli and inserted into the pET-28a expression vector. After induction with 0.2 mM isopropyl β-D-1-thiogalactopyranoside (IPTG), FtsZ was expressed in E. coli BL21 as inclusion bodies. After purification, the recombinant FtsZ protein showed GTPase activity. The highest GTPase activity (0.998 nmol/mL/min) of FtsZ was observed at a GTP concentration of 1.25 mM. Several alkaloids were screened by a constructed model of FtsZ inhibitors. Sanguinarine chloride exhibited higher antibacterial activity against E. coli and Salmonella enteritidis (with minimum inhibitory concentrations (MICs) of 0.04–0.16 mg/mL and minimum bactericidal concentrations (MBCs) of 0.16–0.32 mg/mL) than tetrandrine (0.16–0.32 mg/mL) and berberine hydrochloride (0.32–0.64 mg/mL). Berberine hydrochloride prevented FtsZ polymerization in a concentration-dependent manner and bound to FtsZ protein by hydrogen bonding interaction. This study suggested that the FtsZ-based E. coli screening model could be exploited for the development of novel antibacterial agents for clinical applications.