Enhancing the degradation of Aflatoxin B1 by co-cultivation of two fungi strains with the improved production of detoxifying enzymes

Isolation and evaluation of probiotics from traditional Chinese foods for aflatoxin B1 detoxification: Geotrichum candidum XG1 (yeast) and mechanistic insights

Identifying aflatoxin-detoxifying probiotics remains a significant challenge in mitigating the risks associated with aflatoxin contamination in crops. Biological detoxification is a popular technique that reduces mycotoxin hazards and garners consumer acceptance. Through multiple rounds of screening and validation tests, Geotrichum candidum XG1 demonstrated the ability to degrade aflatoxin B1 (AFB1) by 99-100%, exceeding the capabilities of mere adsorption mechanisms. Notably, the degradation efficiency was demonstrably influenced by the presence of copper and iron ions in the liquid medium, suggesting a potential role for proteases in the degradation process. Subsequent validation experiments with red pepper revealed an 83% reduction in AFB1 levels following fermentation with G. candidum XG1. Furthermore, mass spectrometry analysis confirmed the disruption of the AFB1 furan ring structure, leading to a subsequent reduction in its toxicity. Collectively, these findings establish G. candidum XG1 as a promising candidate for effective aflatoxin degradation, with potential applications within the food industry.

Screening and identification of an aflatoxin B1-degrading strain from the Qinghai-Tibet Plateau and biodegradation products analysis

This research aimed to address the issue of aflatoxin B1 (AFB1) contamination, which posed severe health and economic consequences. This study involved exploring unique species resources in the Qinghai-Tibet Plateau, screening strains capable of degrading AFB1. UPLC-Q-Orbitrap HRMS and NMR were employed to examine the degradation process and identify the structure of the degradation products. Results showed that Bacillus amyloliquefaciens YUAD7, isolated from yak dung in the Qinghai-Tibet Plateau, removed 91.7% of AFB1 from TSB-AFB1 medium with an AFB1 concentration of 10 μg/mL (72 h, 37°C, pH 6.8) and over 85% of AFB1 from real food samples at 10 μg/g (72 h, 37°C), exhibiting strong AFB1 degradation activity. Bacillus amyloliquefaciens YUAD7's extracellular secretions played a major role in AFB1 degradation mediated and could still degrade AFB1 by 43.16% after boiling for 20 min. Moreover, B. amyloliquefaciens YUAD7 demonstrated the capability to decompose AFB1 through processes such as hydrogenation, enzyme modification, and the elimination of the -CO group, resulting in the formation of smaller non-toxic molecules. Identified products include C12H14O4, C5H12N2O2, C10H14O2, C4H12N2O, with a structure consisting of dimethoxyphenyl and enoic acid, dimethyl-amino and ethyl carbamate, polyunsaturated fatty acid, and aminomethyl. The results indicated that B. amyloliquefaciens YUAD7 could be a potentially valuable strain for industrial-scale biodegradation of AFB1 and providing technical support and new perspectives for research on biodegradation products.

A Magnetic Reduced Graphene Oxide Nanocomposite: Synthesis, Characterization, and Application for High-Efficiency Detoxification of Aflatoxin B1

(1) Background: Safety problems associated with aflatoxin B1 (AFB1) contamination have always been a major threat to human health. Removing AFB1 through adsorption is considered an attractive remediation technique. (2) Methods: To produce an adsorbent with a high AFB1 adsorption efficiency, a magnetic reduced graphene oxide composite (Fe3O4@rGO) was synthesized using one-step hydrothermal fabrication. Then, the adsorbent was characterized using a series of techniques, such as SEM, TEM, XRD, FT-IR, VSM, and nitrogen adsorption-desorption analysis. Finally, the effects of this nanocomposite on the nutritional components of treated foods, such as vegetable oil and peanut milk, were also examined. (3) Results: The optimal synthesis conditions for Fe3O4@rGO were determined to be 200 °C for 6 h. The synthesis temperature significantly affected the adsorption properties of the prepared material due to its effect on the layered structure of graphene and the loading of Fe3O4 nanoparticles. The results of various characterizations illustrated that the surface of Fe3O4@rGO had a two-dimensional layered nanostructure with many folds and that Fe3O4 nanoparticles were distributed uniformly on the surface of the composite material. Moreover, the results of isotherm, kinetic, and thermodynamic analyses indicated that the adsorption of AFB1 by Fe3O4@rGO conformed to the Langmuir model, with a maximum adsorption capacity of 82.64 mg·g-1; the rapid and efficient adsorption of AFB1 occurred mainly through chemical adsorption via a spontaneous endothermic process. When applied to treat vegetable oil and peanut milk, the prepared material minimized the loss of nutrients and thus preserved food quality. (4) Conclusions: The above findings reveal a promising adsorbent, Fe3O4@rGO, with favorable properties for AFB1 adsorption and potential for food safety applications.

Prediction and validation of enzymatic degradation of aflatoxin M1: Genomics and proteomics analysis of Bacillus pumilus E-1-1-1 enzymes

Aflatoxins are a class of highly toxic mycotoxins. Aflatoxin M1 (AFM1) is hydroxylated metabolite of aflatoxin B1, having comparable toxicity, which is more commonly found in milk. In this study, the whole genome sequencing of Bacillus pumilus E-1-1-1 isolated from feces of 38 kinds of animals, having aflatoxin M1 degradation ability was conducted. Bacterial genome sequencing indicated that a total of 3445 sequences were finally annotated on 23 different cluster of orthologous groups (COG) categories. Then, the potential AFM1 degradation proteins were verified by proteomics; the properties of these proteins were further explored, including protein molecular weight, hydrophobicity, secondary structure prediction, and three-dimensional structures. Bacterial genome sequencing combined with proteomics showed that eight genes were the most capable of degrading AFM1 including three catalases, one superoxide dismutase, and four peroxidases to clone. These eight genes with AFM1 degrading capacity were successfully expressed. These results indicated that AFM1 can be degraded by Bacillus pumilus E-1-1-1 protein and the most degrading proteins were oxidoreductases.

Edible fungi efficiently degrade aflatoxin B1 in cereals and improve their nutritional composition by solid-state fermentation

Aflatoxin B₁ (AFB₁) is extremely harmful to human and livestock. Laccase, a green catalyst, has been shown to effectively degrade AFB₁ and can be obtained from edible fungi. The objective of this study was to screen edible fungi with high laccase activity and determine their effects on the degradation of AFB₁ in cereals and the nutritional composition of the cereals through solid-state fermentation. Results from plate assays confirmed that 51 of the 55 tested edible fungi could secrete laccase. Submerged fermentation results showed that 17 of the 51 edible fungi had maximum laccase activity exceeding 100 U/L. The growth of different edible fungi varied significantly in corn, rice and wheat. More importantly, 6 edible fungi with high laccase activity and good growth could efficiently degrade AFB₁ in cereals. We found for the first time that Ganoderma sinense could not only secrete highly active laccase and efficiently degrade AFB₁ in corn by 92.91%, but also improve the nutritional quality of corn. These findings reveal that solid-state fermentation of cereals with edible fungi is an environmentally friendly and efficient approach for degrading AFB₁ in cereals and improving the nutritional composition of cereals.

Mechanisms and transformed products of aflatoxin B1 degradation under multiple treatments: a review

Aflatoxins, including aflatoxin B1, B2, G1, G2, M1, and M2, are one of the major types of mycotoxins that endangers food safety, human health, and contribute to the immeasurable loss of food and agricultural production in the world yearly. In addition, aflatoxin B1 (AFB1) mainly produced by Aspergilus sp. is the most potent of these compounds and has been well documented to cause the development of hepatocellular carcinoma in humans and animals. This paper reviewed the detoxification and degradation of AFB1, including analysis and summary of the major technologies in physics, chemistry, and biology in recent years. The chemical structure and toxicity of the transformed products, and the degradation mechanisms of AFB1 are overviewed and discussed in this presented review. In addition to the traditional techniques, we also provide a prospective study on the use of emerging detoxification methods such as natural products and photocatalysis. The purpose of this work is to provide reference for AFB1 control and detoxification, and to promote the development of follow-up research.

Improved Foods Using Enzymes from Basidiomycetes

Within the kingdom of fungi, the division Basidiomycota represents more than 30,000 species, some with huge genomes indicating great metabolic potential. The fruiting bodies of many basidiomycetes are appreciated as food (“mushrooms”). Solid-state and submerged cultivation processes have been established for many species. Specifically, xylophilic fungi secrete numerous enzymes but also form smaller metabolites along unique pathways; both groups of compounds may be of interest to the food processing industry. To stimulate further research and not aim at comprehensiveness in the broad field, this review describes some recent progress in fermentation processes and the knowledge of fungal genetics. Processes with potential for food applications based on lipases, esterases, glycosidases, peptidases and oxidoreductases are presented. The formation and degradation of colourants, the degradation of harmful food components, the formation of food ingredients and particularly of volatile and non-volatile flavours serve as examples. In summary, edible basidiomycetes are foods—and catalysts—for food applications and rich donors of genes to construct heterologous cell factories for fermentation processes. Options arise to support the worldwide trend toward greener, more eco-friendly and sustainable processes.