Detoxification Of Aflatoxin B1 Research Articles

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.

Phytochemicals analysis and aflatoxin B1 detoxification potential of leaves extract of Moringa oleifera and Calotropis procera

The present study aimed to identify the presence of certain classes of phytochemicals in the leaf extract of medicinal herbs viz. Moringa oleifera and Calotropis procera, using qualitative detection tests and explored the potential of aqueous and ethanolic extract to inhibit aflatoxin production by thin layer chromatography at 25 °C and pH (7) of different incubation times i.e. 0-, 1-, 3-, 6- and 24-h. Qualitative phytochemical analysis reported that the aqueous leave extracts of M. oleifera and C. procera contained tannins, phlobatannins, quinones, steroids, sugar, betacyanins, fatty acids, phenols, and volatile oils. Aflatoxin analysis reported that the ethanolic extract of M. oleifera was found more effective than detoxifying 100% of AFB1 after 24 h of incubation. In the case of C. procera, the aqueous extract reduced 96.5% of AFB1 and ethanolic extract reduced 96% of AFB1 after 24-h of incubation. The results revealed that natural plant products have a high potential to reduce AFB1 and could contribute to mitigation plans for AFB1. There is a need for further characterisation using techniques such as GC-MS, LC-MS, or NMR which would provide valuable information on the chemical composition of the extracts.

Food-Grade Expression of Two Laccases in Pichia pastoris and Study on Their Enzymatic Degradation Characteristics for Mycotoxins.

Mycotoxin contamination poses substantial health risks to humans and animals. In this study, the two laccases PpLac1 and AoLac2 from Pleurotus pulmonarius and Aspergillus oryzae were selected and heterologously expressed in Pichia pastoris in a food-grade manner to detoxify aflatoxin B1 (AFB1), zearalenone (ZEN), and deoxynivalenol (DON). Both laccases exhibited degradation activity toward these three mycotoxins, while the efficiency of these for DON was relatively low. Therefore, molecular docking between these laccases and DON was conducted to analyze their potential interaction mechanisms. Furthermore, the degradation conditions of AFB1 and ZEN by the two laccases were optimized, and the optimal degradation rates for AFB1 and ZEN by PpLac1 reached 78.51 and 78.90%, while those for AFB1 and ZEN by AoLac2 reached 72.27 and 80.60%, respectively. The laccases PpLac1 and AoLac2 successfully transformed AFB1 and ZEN into the compounds AFQ1 and 15-OH-ZEN, which were 90 and 98% less toxic than the original compounds, respectively. Moreover, the culture supernatants demonstrated effective mycotoxin degradation results for AFB1 and ZEN in contaminated feed samples. The residual levels of AFB1 and ZEN in all samples ranged from 6.61 to 8.72 μg/kg and 3.44 to 98.15 μg/kg, respectively, and these levels were below the limit set by the European Union standards. All of the results in this study indicated that the two laccases have excellent application potential in the feed industry.

Targeted Detoxification of Aflatoxin B1 in Edible Oil by an Enzyme-Metal Nanoreactor.

Mycotoxin contamination is an important issue for food safety and the environment. Removing mycotoxins from food without losing nutrients and flavor components remains a challenge. In this study, a novel strategy was proposed for the targeted removal of aflatoxin B1 (AFB1) from peanut oil using an amphipathic enzyme-metal hybrid nanoreactor (PL-GOx-Fe3O4@COF) constructed with covalent organic frameworks (COFs) which can selectively adsorb AFB1. Due to the confined space provided by COFs and the proximity effect between GOx and Fe3O4, the detoxification of AFB1 is limited in the nanoreactor without affecting the composition and properties of the oil. The detoxification efficiency of AFB1 in the chemoenzymatic cascade reaction catalyzed by PL-GOx-Fe3O4@COF is six times higher than that of the combination of free GOx and Fe3O4. The AFB1 transformation product has nontoxicity to kidney and liver cells. This study provides a powerful tool for the targeted removal of mycotoxins from edible oils.

Potential of gaseous ozone to inhibit Aspergillus flavus and detoxify aflatoxin B1 in agar and broth media (solid and liquid food states) at different growth phases

Agricultural food crops are prone to Aspergillus flavus contamination during post-harvest and storage stages. Their consumption is toxic due to aflatoxin production, a potent carcinogenic and immunosuppressive agent. Present study explored the ozone's effect as a function of food media states (solid and liquid) to inhibit Aspergillus flavus under three modes of treatment (0th-day, Every-day and Nth-day ozone treatment), that adds novelty to the work. Results showed that ozone concentration to treat Aspergillus flavus and aflatoxins is higher in liquid than solid food state. Further, ozone treatment affected the intactness of fungal spores and inhibited 100% conidial growth. It also exhibited 88 %% inhibition and 90% reduced biomass in solid and liquid food states. Effectiveness of ozone towards inhibiting Aspergillus flavus and aflatoxin was in the following order: Nth -day treatment > Every-day treatment > 0th -day ozone treatment. Further, growth studies showed ozone treated cultures exhibit delayed sporulation and aflatoxin production by 72 h. when cultured on fresh media. Additionally, ozone purging into extracted aflatoxin led to > 99% degradation. The above results show the significance of ozone technology in increasing the shelf-life of post-harvested food crops. Further, it can be used as a disinfectant in the food industry to treat contaminated food crops/liquid products by detoxifying aflatoxins.

Fe-Co-Based Metal-Organic Frameworks as Peroxidase Mimics for Sensitive Colorimetric Detection and Efficient Degradation of Aflatoxin B1.

Building multifunctional platforms for integrating the detection and control of hazards has great significance in food safety and environment protection. Herein, bimetallic Fe-Co-based metal-organic frameworks (Fe-Co-MOFs) peroxidase mimics are prepared and applied to develop a bifunctional platform for the synergetic sensitive detection and controllable degradation of aflatoxin B1 (AFB1). On the one hand, Fe-Co-MOFs with excellent peroxidase-like activity are combined with target-induced catalyzed hairpin assembly (CHA) to construct a colorimetric aptasensor for the detection of AFB1. Specifically, the binding of aptamer with AFB1 releases the prelocked Trigger to initiate the CHA cycle between hairpin H2-modified Fe-Co-MOFs and hairpin H1-tethered magnetic nanoparticles to form complexes. After magnetic separation, the colorimetric signal of the supernatant in the presence of TMB and H2O2 is inversely proportional to the target contents. Under optimal conditions, this biosensor enables the analysis of AFB1 with a limit of detection of 6.44 pg/mL, and high selectivity and satisfactory recovery in real samples are obtained. On the other hand, Fe-Co-MOFs with remarkable Fenton-like catalytic degradation performance for organic contaminants are further used for the detoxification of AFB1 after colorimetric detection. The AFB1 is almost completely removed within 120 min. Overall, the introduction of CHA improves the sensing sensitivity; efficient postcolorimetric-detection degradation of AFB1 reduces the secondary contamination and risk to the experimental environment and operators. This strategy is expected to provide ideas for designing other multifunctional platforms to integrate the detection and degradation of various hazards.

Microbial Composition of Water Kefir Grains and Their Application for the Detoxification of Aflatoxin B1.

Water kefir grains (WKGs), the starter used to develop a traditional beverage named water kefir, consist of a symbiotic mixture of probiotics with diverse bioactivities, but little is known about their abilities to remove mycotoxins that have serious adverse effects on humans and animals. This study investigated the ability of WKGs to remove aflatoxin B1 (AFB1), one of the most toxic mycotoxins, under different settings, and determined the mechanism of absorption mediated by WKGs and the effect of WKGs on the toxicity induced by AFB1 and the reduction in AFB1 in cow milk and tea soups. The results showed the WKGs used herein were dominated by Lactobacillus, Acetobacter, Phenylobacterium, Sediminibacterium, Saccharomyces, Issatchenkia, and Kodamaea. HPLC analysis demonstrated that the WKGs effectively removed AFB1 at concentrations ranging from 1 to 5 µg/mL, pH values ranging from 3 to 9, and temperatures ranging from 4 to 45 °C. Additionally, the removal of AFB1 mainly depended on absorption, which was consistent with the Freundlich and pseudo-second-order kinetic models. Moreover, only 49.63% of AFB1 was released from the AFB1-WKG complex after four washes when the release of AFB1 was non-detectable. Furthermore, WKG treatment caused a dramatic reduction in the mutagenicity induced by AFB1 according to an Ames test and reduced more than 54% of AFB1 in cow milk and three tea soups. These results suggested that WKGs can act as a potential bio-absorbent with a high binding ability to detoxify AFB1 in food and feed via a chemical action step and multi-binding sites of AFB1 absorption in a wide range of scenarios.

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.

Phytochemical screening, antioxidant activity of selected methanolic plant extracts and their detoxification capabilities against AFB1 toxicity

Aflatoxin B1 (AFB1) is a secondary metabolite produced principally by Aspergillus parasiticus and A. flavus. It is one of the most potent and commonly occurring dietary carcinogen with its carcinogenic potential being linked to the formation of DNA adducts and reactive oxygen species (ROS). Plant extracts contain a plethora of biologically active phytochemicals that act against ROS. This study aimed to assess the phytochemical content and antioxidant activity of methanolic extracts of some medicinal plants and investigate their detoxification potentials against AFB1. Phytochemical screening together with total phenolic content (TPC), total flavonoid content (TFC), and antioxidant (2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS+)) assays) were performed on nine methanolic plant extracts. Extracts were incubated with AFB1 for 24 and 48 h and liquid chromatography mass spectrometry (LC-MS) analysis done to assess their AFB1 detoxification activities. The TPC of the extracts ranged from 88.92 ± 6.54 to 210.19 ± 7.90 mg GAE/g, while TFC ranged between 4.01 ± 0.94 and 32.48 ± 1.02 mg QE/g. Radical scavenging activities of extracts varied from 4.18 ± 1.37 to 251.53 ± 9.30 μg/mL and 8.36 ± 1.65 to 279.22 ± 8.33 μg/mL based on DPPH and ABTS+ assays, respectively. Six of the plant extracts showed a time-dependent detoxification activity against AFB1 after 48 h ranging from 20.17 to 38.13 %. C. dentata bark extract showed the highest percentage of AFB1 reduction, with mean percentages of 43.57 and 70.96 % at 24 and 48 h, respectively. This was followed by C. asiatica leaves and A. melegueta seeds with a maximum of 40.81 and 38.13 %, respectively after 48 h. These extracts also possessed high TPC, TFC, and antioxidant activities compared to all the other extracts. Findings from this study demonstrate the abundance of bioactive compounds with antioxidant activity playing a role in potent AFB1 detoxification activity.

Bile Acids Promote Hepatic Biotransformation and Excretion of Aflatoxin B1 in Broiler Chickens.

Aflatoxin B1 (AFB1) is a hazardous mycotoxin that often contaminates animal feed and may potentially induce severe liver damage if ingested. The liver is the primary organ responsible for AFB1 detoxification through enzyme-catalyzed xenobiotic metabolism and bile acid (BA)-associated excretion. In this study, we sought to investigate whether exogenous BA improves hepatic AFB1 detoxification to alleviate AFB1-induced liver injury in broiler chickens. Five-day-old broiler chicks were randomly assigned to three groups. CON and AFB1 received a basal diet; AFB1 + BA received a basal diet with 250 mg/kg BA for 20 days. After a 3-day pre-feed, AFB1 and AFB1 + BA were daily gavaged with 250 μg/kg BW AFB1, while CON received gavage solvent for AFB1 treatment. Dietary BA supplementation protected chickens from AFB1-induced hepatic inflammation and oxidative stress. The hepatic biotransformation of AFB1 to its metabolite AFBO was improved, with accelerated excretion to the gallbladder and cecum. Accordantly, AFB1-induced down-regulation of detoxification genes, including cytochrome P450 enzymes, glutathione S-transferases, and the bile salt export pump, was rescued by BA supplementation. Moreover, liver X receptor α, suppressed by AFB1, was enhanced in BA-treated broiler chickens. These results indicate that dietary BA supplementation improves hepatic AFB1 detoxification and excretion through LXRα-involved regulation of xenobiotic enzymes.

Potential of Animal Excreta as a Source of Probiotic Lactic Acid Bacteria for Aflatoxin B1 Detoxification by the Surface Binding Mechanism

Aflatoxins (AFs) are the most potent and ubiquitously found mycotoxins, capable of causing contamination in agricultural products. Aflatoxin B1 (AFB1) is the most toxic and primarily produced Aflatoxin and will be a real threat to the safety of food and feeds. The current study searched for the potential of Lactic acid bacteria (LAB) isolated from animal excreta for AFB1 mitigation. Three LAB out of 56 isolates were found to exhibit more than 50% sorbent action with AFB1 in phosphate-buffered saline (PBS) and were identified as Lactococcuslactis strain CF_6 (OP183481) (65.38%), Lacticaseibacillus casei strain CW_3 (OP183482)(52.63%) and Lactobacillus acidophilus strain CE_4 (OP183483)(63.13%). More than 60% of the total AFB1 removal was observed in 2 hr of incubation, and maximum sorbent action was found at a pH 6-7 range at 37oC for 24 hours. In the Scanning Electron Microscope (SEM) analysis, heat-killed cells showed a significant increase in cell surface binding area, which improved the surface binding for all isolates except L. casei strain CW_3; however, it proves that LAB surface binding is strain-specific rather than heat treatment. Moreover, the rise in AFB1 concentration improved the rate of the sorbent action but did not observe any substantial changes in total AFB1 detoxification. So, it is concluded that the animal excreta may be a versatile source of probiotic LAB for AFB1 detoxification by surface binding.

Activate hydrogen peroxide for facile and efficient removal of aflatoxin B1 by magnetic Pd-chitosan/rice husk-hercynite biocomposite and its impact on the quality of edible oil

Due to the high heat and chemical stability of aflatoxin B1 (AFB1) with significant impacts on humans/animals and thus it needs to develop a practical and efficient approach for its removal. Herein, we fabricated a magnetic Pd-chitosan/glutaraldehyde/rice husk/hercynite (Pd@CRH-x) composite for efficient detoxification of AFB1. The Pd@CRH-x was obtained by a simple wet-impregnation procedure of CRH complexes followed by pyrolysis. The results confirmed that the unique structure of Pd@CRH-400 effectively improves dispersity, and mass transfer subsequently enhancing removal efficiency in batch conditions. Results indicate 94.30 % of AFB1 was efficiently degraded by 0.1 mg mL−1 Pd@CRH-400 with 4.0 mM H2O2 at wide pH ranges (3.0–10) at 60 min with a decomposition rate constant of 0.0467 min−1. Besides, by comparing the quality factors of edible oil (i.e., acid value, peroxide value, iodine value, moisture, volatile matters, anisidine value, and fatty acid composition), it was confirmed that there was no obvious influence on the physicochemical indicators of edible oil after removal/storage process. Subsequently, the systematic kinetic study and AFB1 degradation mechanism were presented. This study provides a new strategy for the efficient construction of controllable and dispersed Pd-based catalysts using CRH-x as a spatial support for alleviating the risk of toxic pollutants.

Improvement of aflatoxin B1 degradation ability by Bacillus licheniformis CotA-laccase Q441A mutant

Aflatoxin B1 (AFB1) contamination seriously threatens nutritional safety and common health. Bacterial CotA-laccases have great potential to degrade AFB1 without redox mediators. However, CotA-laccases are limited because of the low catalytic activity as the spore-bound nature. The AFB1 degradation ability of CotA-laccase from Bacillus licheniformis ANSB821 has been reported by a previous study in our laboratory. In this study, a Q441A mutant was constructed to enhance the activity of CotA-laccase to degrade AFB1. After the site-directed mutation, the mutant Q441A showed a 1.73-fold higher catalytic efficiency (kcat/Km) towards AFB1 than the wild-type CotA-laccase did. The degradation rate of AFB1 by Q441A mutant was higher than that by wild-type CotA-laccase in the pH range from 5.0 to 9.0. In addition, the thermostability was improved after mutation. Based on the structure analysis of CotA-laccase, the higher catalytic efficiency of Q441A for AFB1 may be due to the smaller steric hindrance of Ala441 than Gln441. This is the first research to enhance the degradation efficiency of AFB1 by CotA-laccase with site-directed mutagenesis. In summary, the mutant Q441A will be a suitable candidate for highly effective detoxification of AFB1 in the future.

Biodegradation of aflatoxin B1 by Aspergillus terreus HNGD-TM15 and its degradation mechanism

Abstract The Aspergillus terreus strain HNGD-TM15 that was isolated from soil grown with rosemary was shown to efficiently degrade aflatoxin B1 (AFB1). Specifically, AFB1 was degraded by the strain’s fermentation broth at a maximum degradation rate of 98.3%. HPLC and LC-MS analyses detected a degradation product with an m/z ion value of 312.0636. Its molecular formula was C18H39NO3, which was tentatively identified as 2-amino-1, 3,4-octadecatriol. Based on LC-MS results and further analysis, it was revealed that a series of reactions, such as decomposition, reduction (lactone ring hydrogenation) and substitution (hydrolysis), occurred during the degradation of AFB1. Therefore, A. terreus HNGD-TM15 has a great potential for application in the detoxification of AFB1 contaminating food and feed products.

Comparative metabolism of aflatoxin B1 in mouse, rat and human primary hepatocytes using HPLC–MS/MS

Aflatoxin B1 (AFB1) is a highly hepatotoxic and carcinogenic mycotoxin produced by Aspergillus species. The compound is mainly metabolized in the liver and its metabolism varies between species. The present study quantified relevant AFB1- metabolites formed by mouse, rat, and human primary hepatocytes after treatment with 1 µM and 10 µM AFB1. The use of liquid chromatographic separation coupled with tandem mass spectrometric detection enabled the selective and sensitive determination of phase I and phase II metabolites of AFB1 over incubation times of up to 24 h. The binding of AFB1 to macromolecules was also considered. The fastest metabolism of AFB1 was observed in mouse hepatocytes which formed aflatoxin P1 as a major metabolite and also its glucuronidated form, while AFP1 occurred only in traces in the other species. Aflatoxin M1 was formed in all species and was, together with aflatoxin Q1 and aflatoxicol, the main metabolite in human cells. Effective epoxidation led to high amounts of DNA adducts already 30 min post-treatment, especially in rat hepatocytes. Lower levels of DNA adducts and fast DNA repair were found in mouse hepatocytes. Also, protein adducts arising from reactive intermediates were formed rapidly in all three species. Detoxification via glutathione conjugation and subsequent formation of the N-acetylcysteine derivative appeared to be similar in mice and in rats and strongly differed from human hepatocytes which did not form these metabolites at all. The use of qualitative reference material of a multitude of metabolites and the comparison of hepatocyte metabolism in three species using advanced methods enabled considerations on toxification and detoxification mechanisms of AFB1. In addition to glutathione conjugation, phase I metabolism is strongly involved in the detoxification of AFB1.

Detoxification of aflatoxin B1 by Bacillus aryabhattai through conversion of double bond in terminal furan.

This study aimed to screen a bacterial strain with high detoxifying capability for aflatoxin B1 (AFB1), verify its biotransformation efficiency, and detoxification process. Three hundred and fifty samples collected from different environmental niche were screened using coumarin as the sole carbon source. HPLC was used to detect residues of AFB1, and 16S rRNA sequencing was performed on the isolated strain with highest AFB1 removal ratio for identification. The detoxified products of this strain were tested for toxicity in E. coli as well as LO2, Caco-2 and HaCaT human cell lines. HPLC-MS was applied to further confirm AFB1 removal and detoxification process. We identified a strain from plant leaf designated as DT with high AFB1-detoxifying ability that is highly homologous to Bacillus aryabhattai. The optimum detoxification conditions of this strain were 37°C and pH 8.0, resulting in 82.92% removal ratio of 2μg mL-1 AFB1 in 72h. The detoxified products were nontoxic for E. coli and significantly less toxic for the LO2, Caco-2 and HaCaT human cell lines. HPLC-MS analysis also confirmed the significant drop of the AFB1 characteristic peak. Two possible metabolic products, C19H15O8 (m/z 371) and C19H19O8 (m/z 375), were observed by mass spectrometry. Potential biotransformation pathway was based on the cleavage of double bond in the terminal furan of AFB1. These generated components had different chemical structures with AFB1, manifesting that the attenuation of AFB1 toxicity would be attributed to the destruction of lactone structure of AFB1 during conversion process.

The potential of lactic acid bacteria isolated from ikan budu (fermented fish) to inhibit the growth of pathogenic fungi and detoxify aflatoxin B1.

Market demand for safe feed and food supply and consumer preferences for safe and healthy products are increasing. Control measures to counter threats to the feed supply need to be implemented as early as possible to prevent economic losses. Mycotoxins produced by certain groups of fungi are a problem that can disrupt the feed supply or pose a threat to the health of animals and humans. Biological control to detoxify contaminated feed ingredients can be carried out on a large scale economically. For example, lactic acid bacteria (LAB) can act as biological agents for eliminating mycotoxins. This study aimed to clarify the value of screening LAB to inhibit Aspergillus flavus growth and detoxify aflatoxin B1 (AFB1). In this study, using a completely randomized design with three replications, five isolates of LAB (LA.1, LA.6, LA.8, LA.12, and LA.22) along with their supernatants were tested qualitatively and quantitatively for their ability to counter mycotoxins using A. flavus and corn kernels. The isolates with the best activity were identified by sequencing 16S rDNA. The results showed that the five LAB isolates can inhibit the growth of A. flavus and detoxify AFB1. Among these isolates, LA.12 showed the best performance, followed by LA.22, LA.8, LA.6, and then LA.1. The sequencing results confirmed that LA.12 was Lactobacillus harbinensis strain 487. All of the isolates in this study have the potential as biological agents for detoxifying AFB1, with isolate LA.12 appearing to be the most promising biodetoxification agent for feed (AFB1 in corn) based on its ability to inhibit pathogenic fungi.

Efficient Aflatoxin B1 degradation by a novel isolate, Pseudomonas aeruginosa M-4

Aflatoxin B1 (AFB1) is the most common mycotoxin with the highest toxicity, posing a threat for food contamination. In this study, the bacterium Pseudomonas aeruginosa M-4 was isolated from rotten wood, and its culture supernatant showed a 56.79% AFB1 degradation rate. Treatment with proteinase K, sodium dodecyl sulfate, and trichloroacetic acid decreased the AFB1 degradation rate in the culture supernatant to 20.71%, 10.83%, and 19.62%, respectively. Moreover, heating the culture supernatant at 121 °C for 30 min increased in the AFB1 degradation rate to 84.76%, indicating effective degradation by heat-resistant and inducible extracellular proteins or enzymes. P. aeruginosa M-4 reduced the content of AFB1 in contaminated maize (90.57%, 14 d). Additionally, high-performance liquid chromatography and ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry analyses showed that AFB1 was biotransformed into structurally different compounds, (C17H16O6), (C16H14O5), (C17H14O5), and (C16H10O6). According to the structure-activity relationship, these degradation products were produced by the destruction of partial toxic sites of AFB1, so the toxicity of these products may be lower than that of AFB1. Thus, P. aeruginosa M-4 has excellent potential for application in the detoxification of AFB1 in food and feed.

In Vitro Mycotoxin Decontamination by Saccharomyces cerevisiae Strains Isolated from Bovine Forage

Aflatoxin B1 (AFB1) and Zearalenone (ZEN) are among the most common and important mycotoxin contaminants in agricultural products, with AFB1 comprising a liver carcinogen and ZEN responsible for reproductive dysfunctions. As mycotoxins are heat-stable, their removal is carried out mainly by anti-mycotoxin additives. This includes the yeast Saccharomyces cerevisiae. In this context, this study aimed to evaluate the in vitro detoxification of AFB1 and ZEN at pH 3 and 6 by three S. cerevisiae strains isolated from bovine forage, coded LL74, LL08, and LL83, determining the adsorption and biotransformation capacities of each strain. The yeast were freeze-dried and added, in triplicate, at 0, 0.5, 1.0, 1.5, and 2.0 mg mL−1 to a static gastrointestinal model. Final mycotoxin concentrations were determined by HPLC-FL. The evaluated strains exhibited high mycotoxin adsorption rates (20–55%), especially the LL08 strain, although low biotransformation, both equivalent to a commercial strain. The results indicate that pH does not interfere in AFB1 detoxification, while the use of 2.0 mg mL−1 of the LL83 S. cerevisiae strain led to higher ZEN adsorption at pH 3. The investigated strains indicate the possibility for use in in vivo conditions and high potential for commercial applications, with LL08 as the most promising strain.

Detoxifying mycotoxins and antifungal properties of two rumen-derived Enterococcus species in artificially contaminated corn silages.

Mycotoxins contamination in food and feed has emerged as an issue of serious concern because they pose serious health risks to both humans and livestock. The study aimed to evaluate the effects of two rumen-derived Enterococcus spp. on fermentation and hygienic quality of artificially contaminated corn silages. The toxigenic fungal-infested (FI) and non-fungal infested (NFI) corn was harvested at 1/2 milk line stage and ensiled without additives (CON) or with Enterococcus faecalis (E) or Enterococcus faecium (M). The pH of FI silages was higher than that of NFI silages, the pH in NFI-M was lower than in NFI-CON. Inoculating E. faecium markedly increased lactic acid concentration compared to CON and E silages. Both E. faecium and E. faecalis decreased the deoxynivalenol (DON) and zearalenone (ZEN) concentrations compared with the CON for FI silages, while E. faecium was more effective in eliminating aflatoxin B1 (AFB1 ). The FI silage had higher bacterial and fungal Shannon indexes than NFI silages. The relative abundance (RA) of Aspergillus and Fusarium marked a decline from day 5 to day 90. Inoculating E. faecium and E. faecalis reduced the RA of Penicillium compared to CON. In vitro mycotoxins removal assay indicated that E. faecium was more effective in AFB1 detoxification while having lower detoxifying ZEN capacity than E. faecalis. Inoculating rumen-derived Enterococcus spp. isolates alleviated the negative effects of fungal infestation on the fermentation and hygienic quality of corn silages by changing the microbial communities and detoxifying mycotoxins. © 2023 Society of Chemical Industry.