Zearalenone is a common mycotoxin contaminant in cereals that causes severe economic losses and serious risks to health of human and animals. Many strategies have been devised to degrade ZEN and keep food safe. The hydrolase ZHD101 from Clonostachys rosea, which catalyzes the hydrolytic degradation of ZEN, has been studied widely. In the current research, three new enzymes that have the capacity to detoxify ZEN were identified, namely CLA, EXO, and TRI, showing 61%, 63%, and 97% amino acids identities with ZHD101, respectively. Three coding genes was expressed as heterologous in Escherichia coli BL21. Through biochemical analysis, the purified recombinant CLA, EXO, TRI, and ZHD101 exhibited high activities of degrading ZEN with the specific activity of 114.8 U/mg, 459.0 U/mg, 239.8 U/mg, and 242.8 U/mg. The optimal temperatures of CLA, EXO, TRI, and ZHD101 were 40 °C, 40 °C, 40 °C, and 45 °C, and their optimum pH were 7.0, 9.0, 9.5, and 9.0, respectively. Our study demonstrated that the novel enzymes CLA, EXO, and TRI possessed high ability to degrade ZEN from the model solutions and could be the promising candidates for ZEN detoxification in practical application.

Deoxynivalenol (DON) is a mycotoxin commonly found in cereals. It has strong toxicity with high stability, thus it is easy to remain in food and cause serious poisoning symptoms to consumers. To establish an efficient and simple DON detection system, a biological nano magnetic particle called bacterial magnetosomes (BMs) extracted from magnetotactic bacteria with ultrasonic crushing and magnetic adsorption was used in this study. A single-stranded DNA aptamer specifically binding to DON was coupled to the surface of MBs by two different crosslinking agents, glutaraldehyde and polyethyleneimine (PEI), respectively, to synthesize two kinds of BMs-aptamer complexes for enriching DON. Then, the adsorption rate of the complex to DON was determined by HPLC. In the results, the absolute DON adsorption capacity of 1 mg BMs-aptamer complex was 27.24 ng when glutaraldehyde was used as crosslinker and 27.64 ng when PEI was used as crosslinker. The optimization results of desorption conditions showed that under the optimal elution conditions (DNase I+methanol for 2 times), the elution rate of DON adsorbed by BMs-glutaraldehyde-aptamer reached 72.7%, while the elution rate of DON adsorbed by BMs-PEI-aptamer complex reached 64.1%. Overall, the current study enriched the applications of magnetosomes in mycotoxin detection, and also provides new idea for the efficient enrichment and recovery of DON.

Low-glutamic-acid monosodium glutamate wastewater (L-MSGW), characterized by high (NH₄)₂SO₄ concentrations, presents significant challenges for conventional treatment. γ-Polyglutamic acid (γ-PGA) production using industrial wastewater is an economical and environmentally friendly strategy. In the current study, we isolated and identified Bacillus subtilis GB, which exhibited exceptional tolerance to (NH₄)₂SO₄, and capability for the high-efficiency biosynthesis of γ-PGA using untreated L-MSGW. Fermentation conditions were optimized using single-factor experiments coupled with response surface methodology, followed by scale-up validation in a 5 L fermenter. Under optimal conditions, the maximum γ-PGA yield reached 16.57 g/L with a minimal glutamate consumption of only 4.9 g/L. The study validated the feasibility of efficient γ-PGA production from L-MSGW by B. subtilis GB, providing a novel technical approach and theoretical basis for low-cost treatment and high-value resource utilization of L-MSGW. This study not only demonstrates the low-cost L-MSGW can be used for the high-value γ-PGA by B. subtilis GB but also provides a sustainable and economically viable solution for industrial wastewater treatment.