Degradation Of Aflatoxin B1 Research Articles

A Bacillus subtilis Strain ZJ20 with AFB1 Detoxification Ability: A Comprehensive Analysis.

As a class I carcinogen, aflatoxin can cause serious damage to various tissues and organs through oxidative stress injuries. The liver, as the target organ of AFB1, is the most seriously damaged. Biological methods are commonly used to degrade AFB1. In our study, the aflatoxin B1-degrading strain ZJ20 was screened from AFB1-contaminated feed and soil, and the degradation of AFB1 by ZJ20 was investigated. The whole genome of strain ZJ20 was analyzed, revealing the genomic complexity of strain ZJ20. The 16S rRNA analysis of strain ZJ20 showed 100% identity to Bacillus subtilis IAM 12118. Through whole gene functional annotation, it was determined that ZJ20 has high antioxidant activity and enzymatic activity; more than 100 CAZymes and 11 gene clusters are involved in the production of secondary metabolites with antimicrobial properties. In addition, B. subtilis ZJ20 was predicted to contain a cluster of genes encoding AFB1-degrading enzymes, including chitinase, laccase, lactonase, and manganese oxidase. The comprehensive analysis of B. subtilis provides a theoretical basis for the subsequent development of the biological functions of ZJ20 and the combinatorial enzyme degradation of AFB1.

Isolation and Optimization of Aflatoxin B1 Degradation by Uniform Design and Complete Genome Sequencing of Novel Deep-Sea Kocuria rosea Strain 13.

Aflatoxin B1 is a natural carcinogenic mycotoxin. The biological detoxification of aflatoxin could result in less environmental pollution, more moderate conditions, and less impact on food and feed, and be more convenient than physical and chemical methods. In this study, strain 13 with aflatoxin B1 degradation activity (67.47 ± 1.44%) was isolated and identified as Kocuria rosea. A uniform design was applied to optimize the degradation activity using a software Data Processing System, and a quadratic polynomial stepwise regression model was selected to investigate the relationships between the degradation rate and five independent variables. Furthermore, the optimal degradation conditions (culture temperature of 30 °C, culture time of 4.2 days, seawater ratio of 100%, pH of 7.11, and inoculation dosage of 0.09%) were verified with a degradation rate of 88 ± 0.03%, which was well matched with the predicted value (92.97%) of the model. Complete genome sequencing of Kocuria rosea, conducted with a combination of Illumina and single-molecule real-time sequencing, was used to analyze the genomic features and functions of the strain, which were predicted by the annotation based on seven databases, and may provide insights into the potential of Kocuria rosea, as well as providing a reference for degradation gene and protein mining. These results indicate that Kocuria rosea strain 13 has the ability to degrade aflatoxin B1 efficiently, and it also has the potential to provide aflatoxin-degrading enzymes.

Use of X-Irradiations in Reducing the Waste of Aflatoxin-Contaminated Pistachios and Evaluation of the Physicochemical Properties of the Irradiated Product.

This study investigates the effects of electron beam irradiation (0, 1, 2, 4, and 6 kGy) on Aspergillus flavus, aflatoxin B1 (AFB1), and the physicochemical properties of pistachios. The findings suggested that e-beam significantly reduced the spore population of A. flavus and the concentration of AFB1 at doses of 4 and 6 kGy. Three AFB1 degradation products were detected via LC-MS analysis and their structures were presented. Total phenolic content was improved at a dose of 2 kGy, while antioxidant activity was decreased in all treatments in both DPPH and ABTS assays. The chlorophyll and carotenoid content declined and the color indices changed, leading to a darker color. E-beam at a dose of 2 kGy raised the soluble protein levels and changed the intensity and pattern of protein bands. Irradiation doses of up to 6 kGy enhanced the content of malondialdehyde and total saturated fatty acids while leading to a decline in unsaturated fatty acids. The quality features were adversely affected at doses > 4 kGy. The findings suggest that as an alternative method, e-beam at doses ≥ 2 kGy can effectively decrease fungal load and aflatoxin B1 contamination, and e-beam application at doses ≤ 2 kGy can maintain the physicochemical attributes of pistachios to an acceptable extent.

Porous Graphitic phase carbon nitride/graphene oxide hydrogel microspheres for efficient and recyclable degradation of aflatoxin B1 in peanut oil.

Removal of aflatoxin is an urgent issue in agricultural products. A porous graphitic carbon nitride/graphene oxide hydrogel microsphere (CN/GO/SA) was synthesized and used to degrade AFB1 in peanut oil. CN/GO/SA was characterized by scanning electron micrograph (SEM), X-ray diffraction (XRD) and FT-IR. The introduction of GO significantly improved the adsorption capacity and visible light activity of photocatalysts. About 98.4% AFB1 in peanut oil was removed by 20% CN/GO/SA under visible light for 120min. ‧O2- and h+ were the main active species during photoreaction, and five degradation products were identified by UPLC-Q-Orbitrap MS analysis. At the same time, the quality of treated peanut oil was still acceptable. More importantly, CN/GO/SA showed excellent cycle stability, and the degradation rate of AFB1 in peanut oil remained above 95% after five-time recycling. This work provides a practical way for developing efficient and sustainable photocatalysts to degrade mycotoxins in edible oil.

Photocatalytic degradation of aflatoxin B1 in aqueous medium and non-alcoholic beer using chlorophyllin

Photocatalytic degradation of aflatoxin B1 in aqueous medium and non-alcoholic beer using chlorophyllin

Rhodococcus turbidus PD630 enables efficient biodegradation of aflatoxin B1

Microbial degradation is a promising method for eliminating aflatoxin B1 (AFB1). In this study, we used a co-culture method to screen for microorganisms capable of efficiently degrading AFB1 and identified the strain Rhodococcus turbidus PD630 as a highly effective degrader. Our results demonstrated that PD630 had a high degradation efficiency, and the degradation efficiency of PD630 strain could be further enhanced by AFB1 induction or change of carbon and nitrogen sources. The extracellular fluid of PD630 exhibited the highest AFB1 degradation activity (81.67%), mainly due to the action of extracellular enzymes, with the extracellular enzyme precipitated by 70% saturated ammonium sulfate showing the highest degradation activity (55.01%). This extracellular enzyme maintained high degradation activity over a pH range (7–10) and broad temperature range (10–80 °C). Li+ and Cu2+ were identified as the primary activators of the enzyme, and the AFB1 lactone ring was cleaved and transformed into a substance completely different from the parent compound. In AFB1 contaminated corn, wheat, and peanut substrates, fermentation time, liquid-to-solid ratio, and inoculation amount all significantly impacted the degradation efficiency, with wheat showing the highest degradation efficiency. Additionally, PD630 showed a degradation rate of over 40% for the co-contaminant zearalenone.

THE ABILITY OF Lactiplantibacillus plantarum TSD-10 AND DR-162 TO REDUCE AFLATOXIN AND MICROBIAL CONTAMINATION OF CORN

Feed safety becoming the main factor to produce good quality food. The purpose of this study was to evaluate the ability of lactic acid bacteria in degrading aflatoxin B1, suppressing the growth of contaminant bacteria, and its application on feed. Biological degradation of aflatoxin B1 (AFB1) in liquid cultures and Escherichia coli and Saccharomyces aureus inhibition by Lactobacillus plantarum were examined. Fermentation of corn for 24 hours by L. plantarum was used to determine the ability of LAB to decrease E. coli, coliform, mold, and AFB1 on a solid substrate. This study showed that both L. plantarum TSD-10 and DR-162 could inhibit E. coli growth at 3% and 5% supernatant addition. The addition of 5% L. plantarum DR-162 and TSD-10 could inhibit S. aureus at 97.40% and 97.28%, respectively. Furthermore, viable cells of L. plantarum DR-162 and TSD-10 removed 56.97% and 64.65% AFB1 within 72 h of incubation, respectively. The AFB1 reduction by nonviable cell was lower than the viable cell. The population of E. coli, coliform, and mold completely disappeared in both fermentation treatment of corn by L. plantarum DR-162 and TSD-10 at 3% and 5%. AFB1 significantly decreased by 17.57% and 22.60% on 5% L. plantarum DR-162 and TSD-10 treatment.

Simultaneous degradation of aflatoxin B1 and zearalenone by Porin and Peroxiredoxin enzymes cloned from Acinetobacter nosocomialis Y1

Mycotoxin contamination can cause severe health issues for both humans and animals. This study examined the potential of enzymes derived from Acinetobacter nosocomialis Y1 to simultaneously degrade aflatoxin B1 (AFB1) and zearalenone (ZEN), which could have significant implications in reducing mycotoxin contamination. Two enzymes, Porin and Peroxiredoxin, were identified with molecular weights of 27.8 and 20.8 kDa, respectively. Porin could completely degrade 2 µg/mL of AFB1 and ZEN within 24 h at 80 °C and 60 °C, respectively. Peroxiredoxin could completely degrade 2 µg/mL of AFB1 and reduce ZEN by 91.12% within 24 h. The addition of Na+, Cu2+, and K+ ions enhanced the degradation activities of both enzymes. LC-MS/MS analysis revealed that the molar masses of the degradation products of AFB1 and ZEN were 286 g/mol and 322.06 g/mol, and the products were identified as AFD1 and α or β-ZAL, respectively. Vibrio fischeri bioluminescence assays further confirmed that the cytotoxicity of the two degradation products was significantly lower than that of AFB1 and ZEN. Based on these results, it can be inferred that the degradation product of ZEN is β-ZAL. These findings suggest that both enzymes have the potential to be utilized as detoxification enzymes in food and feed.

Achieving improved efficiency for removal of aflatoxin B1 by combination use of cold atmospheric-pressure plasma and plasma-activated water

A novel approach was employed to remove aflatoxin B1 (AFB1), a very toxic metabolite from Aspergillus flavus (A. flavus), by using cold atmospheric-pressure plasma (CAP) and plasma-activated water (PAW) in combination. The results showed that CAP could efficiently degrade AFB1, while the PAW produced by CAP could further remove AFB1 with a relatively long treatment time. During the CAP processing, hydroxyl radical (·OH) was one of the dominant reactive species, which caused the hydroxylation at furan ring of AFB1, while in PAW treatment, singlet oxygen (1O2) was the major reactive agent for AFB1 degradation, which caused the destruction of the methyl group on the benzene side chain and oxidized the double bond of the terminal furan ring in the AFB1 molecule. This study therefore provides new guidance for the application of plasma technology in the treatment of fungal mycotoxins for food safety.

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.

AFB1 Microbial Degradation by Bacillus subtilis WJ6 and Its Degradation Mechanism Exploration Based on the Comparative Transcriptomics Approach.

Aflatoxin pollution poses great harm to human and animal health and causes huge economic losses. The biological detoxification method that utilizes microorganisms and their secreted enzymes to degrade aflatoxin has the advantages of strong specificity, high efficiency, and no pollution inflicted onto the environment. In this study, Bacillus subtilis WJ6 with a high efficiency in aflatoxin B1 degradation was screened and identified through molecular identification, physiological, and biochemical methods. The fermentation broth, cell-free supernatant, and cell suspension degraded 81.57%, 73.27%, and 8.39% of AFB1, respectively. The comparative transcriptomics analysis indicated that AFB1 led to 60 up-regulated genes and 31 down-regulated genes in B. subtilis WJ6. A gene ontology (GO) analysis showed that the function classifications of cell aggregation, the organizational aspect, and the structural molecule activity were all of large proportions among the up-regulated genes. The down-regulated gene expression was mainly related to the multi-organism process function under the fermentation condition. Therefore, B. subtilis WJ6 degraded AFB1 through secreted extracellular enzymes with the up-regulated genes of structural molecule activity and down-regulated genes of multi-organism process function.

Optimization of aflatoxin B1 degradation in corn by Ganoderma sinense through solid-state fermentation

Corn is a staple cereal worldwide, but it is frequently contaminated with aflatoxin B1 (AFB1) due to extreme weather or poor storage conditions. The consumption of AFB1-contaminated corn poses a significant health risk to humans and livestock. To address this issue, an environmentally friendly, cost-effective, and efficient method for eliminating AFB1 from corn is needed. In this study, Ganoderma sinense strain Gs-1 with the ability to secrete laccase was used to ferment AFB1-contaminated corn to degrade AFB1. The degradation conditions of AFB1 in corn were optimized through single factor experiments and response surface methodology under solid-state fermentation. The optimal conditions for G. sinense to degrade AFB1 were 12 days of fermentation, a moisture content of 65.2% in the corn substrate, an inoculation amount of 5 mL of G. sinense culture (containing 51.85 mg of G. sinense mycelia), and a fermentation temperature of 27.9 °C. Under these optimal conditions, the degradation rate of AFB1 in corn reached 94.03% through solid-state fermentation with G. sinense. This study provides an economical, environmentally friendly, and efficient strategy for degrading AFB1 in corn, which has great application potential in the food and feed industries.

NiCo2S4@ZnIn2S4-Assisted All-in-One Self-Powered electrochemical device for ultrasensitive detection and degradation of AFB1

Self-powered sensors are easy to be integrated and miniaturized without power supply, providing an attractive way to construct smart, portable and implantable device. However, it is challenging to realize practical application especially for food safety problems due to the low energy conversion efficiency and the degradation difficulty of toxins. Herein, a new all-in-one photocatalytic self-powered electrochemical device (SPED) was proposed for the first time to achieve sensitive detection and efficient degradation of aflatoxin B1 (AFB1) by the integration of photocatalytic fuel cell with photocatalytic degradation. NiCo2S4@ZnIn2S4 (NCS@ZIS) heterojunction was used as photoanode material with a high photocurrent of 13.7 μA, improving the photoelectric conversion efficiency greatly. By combining with photocathode, the output power of the SPED was greatly boosted to 467.4 mV, which realized AFB1 detection ranging from 0.001 ng/mL to 1000 ng/mL with a low detection limit of 0.17 pg/mL. In addition, owing to the photocatalysis of NCS@ZIS heterojunction as well as the drive of voltage difference between anode and cathode, the SPED showed a high degradation efficiency up to 81.62 % within 120 min. The successful construction of the all-in-one SPED achieved ultrasensitive detection and degradation of AFB1, demonstrating a great promising application in food security and environmental monitoring areas.

MOF-derived La–ZnFe2O4@Fe3O4@carbon magnetic hybrid composite as a highly efficient and recyclable photocatalyst for mycotoxins degradation

During the planting, storage, or feeding stages, foodstuffs can be easily polluted by mycotoxins such as aflatoxin B1, patulin and zearalenone, which are produced by pathogenic microorganisms. Therefore, the removal of these mycotoxins constitutes an active area of research. Herein, we used an Fe/Zn metal–organic framework (MOF) as a precursor to fabricate a novel La–ZnFe2O4@Fe3O4@carbon magnetic hybrid composite via a simple absorption–pyrolysis method and explored its photocatalytic performance in the degradation of aflatoxin B1, patulin, and zearalenone. La–ZnFe2O4@Fe3O4@carbon can effectively degrade 98.37% of aflatoxin B1, outperforming Fe3O4@carbon (69.57%) and ZnFe2O4@Fe3O4@carbon (91.39%). Moreover, La–ZnFe2O4@Fe3O4@carbon exhibits superior stability and excellent photocatalytic activity for the degradation of patulin (97.35%) and zearalenone (98.52%). Transient photocurrent response measurements reveal that the La doping and the combination with ZnFe2O4 highly promote the separation of photoinduced electron–hole pairs on Fe3O4@carbon. An electron spin resonance analysis suggests that ·OH and ·O2− are the main active radicals during the photodegradation process. Thus, a plausible photodegradation pathway for the degradation of mycotoxins produced by pathogenic microorganisms is proposed.

Aflatoxin B1 Degradation by Ery4 Laccase: From In Vitro to Contaminated Corn.

Aflatoxins (AFs) are toxic secondary metabolites produced by Aspergillus spp. and are found in food and feed as contaminants worldwide. Due to climate change, AFs occurrence is expected to increase also in western Europe. Therefore, to ensure food and feed safety, it is mandatory to develop green technologies for AFs reduction in contaminated matrices. With this regard, enzymatic degradation is an effective and environmentally friendly approach under mild operational conditions and with minor impact on the food and feed matrix. In this work, Ery4 laccase, acetosyringone, ascorbic acid, and dehydroascorbic acid were investigated in vitro, then applied in artificially contaminated corn for AFB1 reduction. AFB1 (0.1 µg/mL) was completely removed in vitro and reduced by 26% in corn. Several degradation products were detected in vitro by UHPLC-HRMS and likely corresponded to AFQ1, epi-AFQ1, AFB1-diol, or AFB1dialehyde, AFB2a, and AFM1. Protein content was not altered by the enzymatic treatment, while slightly higher levels of lipid peroxidation and H2O2 were detected. Although further studies are needed to improve AFB1 reduction and reduce the impact of this treatment in corn, the results of this study are promising and suggest that Ery4 laccase can be effectively applied for the reduction in AFB1 in corn.

Study on the mechanism of aflatoxin B1 degradation by Tetragenococcushalophilus

The degradation conditions of aflatoxin B1 (AFB1) by T. halophilus in MRS liquid culture were studied. The inoculum amount of T. halophilus, fermentation time, and fermentation temperature were recorded as experimental factors, and the degradation rate of AFB1 was measured as the experimental index. AFB1 degradation increased with the increase of temperature, with a maximum value of 75.9 ± 4.92%. When the temperature exceeded 32 °C, the degradation rate showed a downward trend. Experimental results showed that the degradation of AFB1 by T. halophilus was related to the starting concentration of the strain. The molecular weight of the extracellular enzymes that degraded AFB1 ranged from 55 KD to 70 KD,Zn2+ can promote the activity of AFB1 degradation by this enzyme, while Al3+, Ba2+, Ca2+ and Mn2+ can inhibit the activity of AFB1 degradation by this enzyme. Especially, the inhibitory effect of Ca2+ is the strongest, up to 48.54%, and the optimal temperature is 32 °C. The degradation products of AFB1 were identified as M/Z327.08 (C17H10O7) and M/Z285.08 (C16H12O5). Taken together, these results demonstrated that T. halophilus has application potential for AFB1 degradation.

Degradation of Aflatoxin B1 in Moldy Maize by Pseudomonas aeruginosa and Safety Evaluation of the Degradation Products

Aflatoxin B1 (AFB1) is the most harmful mycotoxin commonly found in food and feed. Pollution from AFB1 causes serious economic and health issues worldwide because it causes strong mutagenicity and carcinogenicity in humans and animals. In this study, Pseudomonas aeruginosa was used to degrade AFB1 in moldy maize, and the safety of this biological method was investigated using genotoxicity and cytotoxicity tests. Using response surface methodology, we established the optimal conditions for degrading AFB1 by the fermentation supernatant of P. aeruginosa. Under these conditions, the degradation rate of AFB1 reached 99.67%. Furthermore, the Ames mutagenicity test showed that AFB1 treated with P. aeruginosa fermentation supernatant for 72 h was not mutagenic. CCK-8 cell assay showed that AFB1 cytotoxicity was significantly reduced after degradation. Overall, our findings show that the fermentation supernatant of P. aeruginosa may be a good candidate for biodegradation of AFB1.

Novel ZnO@NPC core–shell polyhedral heterostructures derived from ZIF-8 with enhanced photocatalytic performance for aflatoxin B1 degradation

Aflatoxin is one of the most toxic mycotoxins and causes server threaten to human health and food safety issues. It is crucial to develop efficient materials to remove and degrade aflatoxins. In this work, we adopted PVP modified ZIF-8 as precursor to prepare novel ZnO@NPC core–shell heterostructures (NPC is N-doped porous carbon) via “pyrolysis-in situ transformation-pyrolysis” strategy and used it as catalyst for degradation of aflatoxin B1 (AFB1). Various technologies were adopted to characterize to the structures and properties of the catalyst, such as XRD, SEM, BET, and TEM. The results show that the coating of N-doped porous carbon on ZnO can extend its light absorption wavelength to 800 nm, enhancing its photocatalytic activity for degradation of AFB1 (94.8%). The synergetic effect of high absorption capacity on N-doped porous carbon and excellent photocatalytic activity on ZnO was proven to contribute high degradation performance of ZnO@NPC. ZnO@NPC also shows excellent reparation and reusability. The photocatalytic activity of ZnO@NPC reduces only 1.71% after five repeated cycles. The developed ZnO@NPC may bring a promising solution for toxin degradation.

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.

CotA laccase from Bacillus licheniformis ZOM-1 effectively degrades zearalenone, aflatoxin B1 and alternariol

In the present study, CotA laccase was cloned from Bacillus licheniformis ZOM-1 and expressed in Escherichia coli. In addition to the oxidative degradation of zearalenone (ZEN) and aflatoxin B1 (AFB1), CotA laccase also has the ability to degrade the Alternaria toxin alternariol (AOH). This is the first report of an Alternaria toxin-degrading enzyme. The optimal reaction temperature for CotA laccase is 80 °C, and the optimal reaction pH is approximately 9.0. By high-resolution mass spectrometry, we identified the oxidative degradation products. Additionally, toxicological analysis indicated that the degradation products had a significantly reduced effect on cell viability relative to the original toxins. In addition, we found that B. licheniformis ZOM-1 has the ability to degrade three mycotoxins, ZEN, AOH and alternariol monomethyl ether (AME). These findings provide possible application prospects for CotA laccase and B. licheniformis ZOM-1 as mycotoxin degradation products in food or feed.