Preparation, purification and characteristics of an aflatoxin degradation enzyme from Myxococcus fulvus ANSM068

Biological Detoxification of Aflatoxin B1 by Enterococcus faecium HB2-2

Aflatoxin B1 (AFB1) contamination in food and feed is a global health and economic threat, necessitating the immediate development of effective strategies to mitigate its negative effects. This study focuses on the isolation and characterization of Enterococcus faecium HB2-2 (E. faecium HB2-2) as a potent AFB1-degrading microorganism, using morphological observation, biochemical profiling, and 16S rRNA sequence analysis. An incubation of E. faecium HB2-2 at 32 °C for 96 h in a pH 10 nutrient broth (NB) medium resulted in a remarkable degradation rate of 90.0% for AFB1. Furthermore, E. faecium HB2-2 demonstrated 82.9% AFB1 degradation rate in the peanut meal, reducing AFB1 levels from 105.1 to 17.9 μg/kg. The AFB1 degradation ability of E. faecium HB2-2 was found to be dependent on the fermentation supernatant. The products of AFB1 degradation by E. faecium HB2-2 were analyzed by liquid chromatography-mass spectrometry (LC-MS), and a possible degradation mechanism was proposed based on the identified degradation products. Additionally, cytotoxicity assays revealed a significant reduction in the toxicity of the degradation products compared to the parent AFB1. These findings highlight the potential of E. faecium HB2-2 as a safe and effective method for mitigating AFB1 contamination in food and feed.

The mitigative role of novel aflatoxin-degrading enzymes in diverse broiler performance indicators and gut microbiota following the consumption of diets contaminated with aflatoxins

BACKGROUND

This study aims to explore both the toxic effects of aflatoxins (AFs) and the protective effects of degrading enzymes (DE) on broilers exposed to AFs.

RESULTS

The findings reveal that a diet contaminated with 69.15 μg kg-1 of aflatoxin B1 had significant adverse effects on broilers. Specifically, it led to a reduction in average daily gain, dressed yield percentage, half-eviscerated yield with giblet yield percentage, eviscerated yield percentage, as well as serum superoxide dismutase (SOD), glutathione peroxidase activity and liver SOD activity (P < 0.05). Conversely, the diet increased the feed conversion ratio, liver index, serum glutamic oxaloacetic transaminase levels and malondialdehyde levels in both serum and liver (P < 0.05). Additionally, AFs disrupted the intestinal microflora significantly (P < 0.05), altering the relative abundance of Enterococcus, Lactobacillus and Escherichia in broiler jejunum. The addition of DE to AF-contaminated feed mitigated these negative effects and reduced the residues of aflatoxin B1, aflatoxin B2 and aflatoxin M1 in the liver and duodenum (P < 0.05). We also observed that broilers fed the diet pelleted at 80 °C exhibited improved dressing percentage and water holding capacity compared to those on the 75 °C diet.

CONCLUSION

In summary, DE serves as an effective feed additive for mitigating AF contamination in poultry production. © 2024 Society of Chemical Industry.

Metabolites and degradation pathways of microbial detoxification of aflatoxins: a review

The degradation of aflatoxins using nonpathogenic microbes and their enzymes is emerging as a safe and economical alternative to chemical and physical methods for the detoxification of aflatoxins in food and feeds. Many bacteria and fungi have been identified as aflatoxin degraders. This review is focused on the chemical identification of microbial degradation products and their degradation pathways. The microbial degradations of aflatoxins are initiated by oxidation, hydroxylation, reduction, or elimination reactions mostly catalyzed by various enzymes belonging to the classes of laccase, reductases, and peroxidases. The resulting products with lesser chemical stability further undergo various reactions to form low molecular weight products. Studies on the chemical and biological nature of degraded products of aflatoxins are necessary to ensure the safety of the decontamination process. This review indicated the need for an integrated approach including decontamination studies using culture media and food matrices, proper identification and toxicity profiling of degraded products of aflatoxins, and interactions of microbes and the degradation products with food matrices for developing practical and effective microbial detoxification process.

Recombinant Oxidase from Armillaria tabescens as a Potential Tool for Aflatoxin B1 Degradation in Contaminated Cereal Grain

Forage grain contamination with aflatoxin B1 (AFB1) is a global problem, so its detoxification with the aim of providing feed safety and cost-efficiency is still a relevant issue. AFB1 degradation by microbial enzymes is considered to be a promising detoxification approach. In this study, we modified an previously developed Pichia pastoris GS115 expression system using a chimeric signal peptide to obtain a new recombinant producer of extracellular AFB1 oxidase (AFO) from Armillaria tabescens (the yield of 0.3 g/L), purified AFO, and selected optimal conditions for AFO-induced AFB1 removal from model solutions. After a 72 h exposure of the AFB1 solution to AFO at pH 6.0 and 30 °C, 80% of the AFB1 was degraded. Treatments with AFO also significantly reduced the AFB1 content in wheat and corn grain inoculated with Aspergillus flavus. In grain samples contaminated with several dozen micrograms of AFB1 per kg, a 48 h exposure to AFO resulted in at least double the reduction in grain contamination compared to the control, while the same treatment of more significantly (~mg/kg) AFB1-polluted samples reduced their contamination by ~40%. These findings prove the potential of the tested AFO for cereal grain decontamination and suggest that additional studies to stabilize AFO and improve its AFB1-degrading efficacy are required.

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.

Tuning Thermostability and Catalytic Efficiency of Aflatoxin-Degrading Enzyme by Error-prone PCR

In our previous work, a recombinant aflatoxin-degrading enzyme derived from Myxococcus fulvus (MADE) was reported. However, the low thermal stability of the enzyme had limitations for its use in industrial applications. In this study, we obtained an improved variant of recombinant MADE (rMADE) with enhanced thermostability and catalytic activity using error-prone PCR. Firstly, we constructed a mutant library containing over 5000 individual mutants. Three mutants with T₅₀ values higher than the wild-type rMADE by 16.5 °C (rMADE-1124), 6.5 °C (rMADE-1795), and 9.8 °C (rMADE-2848) were screened by a high-throughput screening method. Additionally, the catalytic activity of rMADE-1795 and rMADE-2848 was improved by 81.5% and 67.7%, respectively, compared to the wild-type. Moreover, structural analysis revealed that replacement of acidic amino acids with basic amino acids by a mutation (D114H) in rMADE-2848 increased the polar interactions with surrounding residues and resulted in a threefold increase in the t_1/2 value of the enzyme and made it more thermaltolerate. KEY POINTS: • Mutant libraries construction of a new aflatoxins degrading enzyme by error-prone PCR. • D114H/N295D mutant improved enzyme activity and thermostability. • The first reported enhanced thermostability of aflatoxins degrading enzyme better for its application.

Biocontrol Capabilities of Bacillus subtilis E11 against Aspergillus flavus In Vitro and for Dried Red Chili (Capsicum annuum L.)

As a condiment with extensive nutritional value, chili is easy to be contaminated by Aspergillus flavus (A. flavus) during field, transportation, and storage. This study aimed to solve the contamination of dried red chili caused by A. flavus by inhibiting the growth of A. flavus and detoxifying aflatoxin B₁ (AFB₁). In this study, Bacillus subtilis E11 (B. subtilis) screened from 63 candidate antagonistic bacteria exhibited the strongest antifungal ability, which could not only inhibit 64.27% of A. flavus but could also remove 81.34% of AFB₁ at 24 h. Notably, scanning electron microscopy (SEM) showed that B. subtilis E11 cells could resist a higher concentration of AFB₁, and the fermentation supernatant of B. subtilis E11 could deform the mycelia of A. flavus. After 10 days of coculture with B. subtilis E11 on dried red chili inoculated with A. flavus, the mycelia of A. flavus were almost completely inhibited, and the yield of AFB₁ was significantly reduced. Our study first concentrated on the use of B. subtilis as a biocontrol agent for dried red chili, which could not only enrich the resources of microbial strains for controlling A. flavus but also could provide theoretical guidance to prolong the shelf life of dried red chili.

Challenges and advancements in bioprocess intensification of fungal secondary metabolite: kojic acid

Kojic acid is a fungal secondary metabolite commonly known as a tyrosinase inhibitor, that acts as a skin-whitening agent. Its applications are widely distributed in the area of cosmetics, medicine, food, and chemical synthesis. Renewable resources are the alternative feedstocks that can fulfill the demand for free sugars which are fermented for the production of kojic acid. This review highlights the current progress and importance of bioprocessing of kojic acid from various types of competitive and non-competitive renewable feedstocks. The bioprocessing advancements, secondary metabolic pathway networks, gene clusters and regulations, strain improvement, and process design have also been discussed. The importance of nitrogen sources, amino acids, ions, agitation, and pH has been summarized. Two fungal species Aspergillus flavus and Aspergillus oryzae are found to be extensively studied for kojic acid production due to their versatile substrate utilization and high titer ability. The potential of A. flavus to be a competitive industrial strain for large-scale production of kojic acid has been studied.

Characteristics of Aflatoxin B1 Degradation by Stenotrophomonas acidaminiphila and It's Combination with Black Soldier Fly Larvae

Aflatoxin B₁ (AFB₁) is a common mycotoxin contaminant in cereals that causes severe economic losses and serious risks to the health of humans and animals. In this paper, we investigated the characteristics of AFB₁ degradation by black soldier fly larvae (BSFL) combined with commensal intestinal microorganisms. Germ-free BSFL and non-sterile BSFL were reared on peanut meal spiked with AFB₁ for 10 days. The result showed that germ-free BSFL and non-sterile BSFL could achieve 31.71% and 88.72% AFB₁ degradation, respectively, which indicated the important role of larvae gut microbiota in AFB₁ degradation. Furthermore, twenty-five AFB₁-degrading bacteria were isolated from BSFL gut, and S. acidaminiphila A2 achieved the highest AFB₁ degradation, by 94%. When S. acidaminiphila A2 was re-inoculated to BSFL, the detrimental effect of AFB₁ on the growth performance of BSFL was alleviated, and complete AFB₁ degradation in peanut meal was obtained. In conclusion, the present study may provide a strategy to degrade AFB₁ in feedstuff through bioconversion with BSFL in combination with gut-originated AFB₁-degrading bacteria, while providing a sustainable insect protein and fat source to animals.

Microbial Enzymes Involved in the Biotransformation of Major Mycotoxins

Mycotoxins, the most researched biological toxins, can contaminate food and feed, resulting in severe health implications for humans and animals. Physical, chemical, and biological techniques are used to mitigate mycotoxin contamination. The biotransformation method using whole microbial cells or isolated enzymes is the best choice to mitigate mycotoxins. Using specific enzymes may avoid the disadvantages of utilizing a full microbe, such as accidental harm to the product's organoleptic characteristics and hazardous safety features. Moreover, the degradation rates of the isolated enzymes are higher than those of the whole-cell reactions, and they are substrate-specific. Their specificity is comprehensive and is shown at the positional and/or chiral center in many circumstances. Currently, only a few enzymes of microbial origin are commercially available. Therefore, there is a need to identify more novel enzymes of microbial origin that can mitigate mycotoxins. In this review, we conducted an in-depth summary of the microbial enzymes involved in the biotransformation of mycotoxins.

Efficacy of the antifungal metabolites of Streptomyces philanthi RL-1-178 on aflatoxin degradation with its application to prevent aflatoxigenic fungi in stored maize grains and identification of the bioactive compound

Aflatoxin B₁ is a potent carcinogen produced by Aspergillus flavus (A. flavus) and Aspergillus. parasiticus (A. parasiticus), mainly during grain storage. The efficacy of the freeze-dried culture filtrate of Streptomyces philanthi (S. philanthi) strain RL-1-178 (DCF) on degradation of aflatoxin B₁ (AFB₁) were evaluated and its bioactive compounds were identified. The DCF at a concentration of 9.0% (w/v) completely inhibited growth and AFB₁ production of A. parasiticus TISTR 3276 and A. flavus PSRDC-4 after 7 days tested in yeast-extract sucrose (YES) medium and on stored maize grains after 28 and 14 days incubation, respectively. This indicated the more tolerance of A. parasiticus over A. flavus. The DCF and bacterial cells of S. philanthi were capable to degrade AFB₁ by 85.0% and 100% for 72 h and 8 days, respectively. This confirmed the higher efficacy of the DCF over the cells. After separation of the DCF on thin-layer chromatography (TLC) plate by bioautography bioassay, each active band was identified by liquid chromatography-quadrupole time of flight mass spectrometer (LC-Q-TOF MS/MS). The results revealed two compounds which were identified as azithromycin and an unknown based on mass ions of both ESI⁺ and ESI^- modes. The antifungal metabolites in the culture filtrate of S. philanthi were proved to degrade aflatoxin B₁. It could be concluded that the DCF may be applied to prevent the growth of the two aflatoxin-producing fungi as well as the occurrence of aflatoxin in the stored maize grains.

Current Review of Mycotoxin Biodegradation and Bioadsorption: Microorganisms, Mechanisms, and Main Important Applications

Mycotoxins are secondary metabolites produced by fungi. Food/feed contamination by mycotoxins is a great threat to food safety. The contamination can occur along the food chain and can cause many diseases in humans and animals, and it also can cause economic losses. Many detoxification methods, including physical, chemical, and biological techniques, have been established to eliminate mycotoxins in food/feed. The biological method, with mycotoxin detoxification by microorganisms, is reliable, efficient, less costly, and easy to use compared with physical and chemical ones. However, it is important to discover the metabolite's toxicity resulting from mycotoxin biodegradation. These compounds can be less or more toxic than the parent. On the other hand, mechanisms involved in a mycotoxin's biological control remain still unclear. Mostly, there is little information about the method used by microorganisms to control mycotoxins. Therefore, this article presents an overview of the most toxic mycotoxins and the different microorganisms that have a mycotoxin detoxification ability. At the same time, different screening methods for degradation compound elucidation are given. In addition, the review summarizes mechanisms of mycotoxin biodegradation and gives some applications.

Characterization of a Trametes versicolor aflatoxin B1-degrading enzyme (TV-AFB1D) and its application in the AFB1 degradation of contaminated rice in situ

Aflatoxin B₁ (AFB₁) contaminates rice during harvest or storage and causes a considerable risk to human and animal health. In this study, Trametes versicolor AFB₁–degrading enzyme (TV–AFB₁D) gene recombinantly expressed in engineered E. coli BL21 (DE3) and Saccharomyces cerevisiae. The TV–AFB₁D enzymatic characteristics and AFB₁ degradation efficiency in contaminated rice were investigated. Results showed that the size of recombinant TV-AFB₁D expressing in E. coli BL21 (DE3) and S. cerevisiae was appropriately 77 KDa. The kinetic equation of TV-AFB₁D was y = 0.01671x + 1.80756 (R² = 0.994, K_m = 9.24 mM, and V_max = 553.23 mM/min). The Kcat and Kcat/K_m values of TV-AFB₁D were 0.07392 (s⁻¹) and 8 M⁻¹ s⁻¹, respectively. The AFB₁ concentration of contaminated rice decreased from 100 μg/ml to 32.6 μg/ml after treatment at 32°C for 5 h under the catabolism of TV-AFB₁D. S. cerevisiae engineered strains carrying aldehyde oxidase 1 (AOX1) and Cauliflower mosaic virus 35 S (CaMV 35 S) promoters caused the residual AFB₁ contents, respectively, decreased to 3.4 and 2.9 μg/g from the initial AFB₁ content of 7.4 μg/g after 24 h of fermentation using AFB₁-contaminated rice as substrate. The AFB₁ degradation rates of S. cerevisiae engineered strains carrying AOX1 and CaMV promoters were 54 and 61%, respectively. Engineered S. cerevisiae strains integrated with TV-AFB₁D expression cassettes were developed to simultaneously degrade AFB₁ and produce ethanol using AFB₁-contaminated rice as substrate. Thus, TV-AFB₁D has significant application potential in the AFB₁ decomposition from contaminated agricultural products.

Considerations regarding affinity determinants for aflatoxin B1 in binding cavity of fungal laccase based on in silico mutational and in vitro verification studies

Laccase, a multicopper oxidase, is well known for its industrial potentials to remove environmental pollutants due to its low substrate specificity to oxidize phenols and thus catalytic versatility. Many efforts focused on the metabolic mechanism, yet to decipher the structural determinants responsible for the differentiation between substrates. Aflatoxin B1 (AFB1), a new substrate for laccase, is a mycotoxin with a formidable environmental threat to public health and food safety. In the present study, we combined biochemical, in silico mutational and molecular-docking data to gain an insight to the function of key residues in the active cavity close to the T1 copper site in a characterized recombinant laccase from Cerrena unicolor (rCuL). Kinetic data for computer-assisted virtual mutants established the binding affinity of hydrogen bonds and residues (Asn336, Asp207, Val391, and Thr165) in rCuL to AFB1. The augmented binding affinity to AFB1 may be related to the conformational rearrangements of the laccase and its ability to hydrogen-bond with the substrate. Furthermore, the optimal pH and temperature for rCuL and variants mediated AFB1 degradation may depend on their pH stability and thermostability. Our findings reinforce the importance of the structure-function relationship of fungal laccases in degrading AFB1, providing mechanistic guidance for future biocatalyst and bioengineering applications.

Isolation, Purification, and Characterization of a Laccase-Degrading Aflatoxin B1 from Bacillus amyloliquefaciens B10

Aflatoxins, widely found in feed and foodstuffs, are potentially harmful to human and animal health because of their high toxicity. In this study, a strain of Bacillus amyloliquefaciens B10 with a strong ability to degrade aflatoxin B1 (AFB1) was screened; it could degrade 2.5 μg/mL of AFB1 within 96 h. The active substances of Bacillus amyloliquefaciens B10 for the degradation of AFB1 mainly existed in the culture supernatant. A new laccase with AFB1-degrading activity was separated by ammonium sulfate precipitation, diethylaminoethyl (DEAE) and gel filtration chromatography. The results of molecular docking showed that B10 laccase and aflatoxin had a high docking score. The coding sequence of the laccase was successfully amplified from cDNA by PCR and cloned into E. coli. The purified laccase could degrade 79.3% of AFB1 within 36 h. The optimum temperature for AFB1 degradation was 40 °C, and the optimum pH was 6.0–8.0. Notably, Mg²⁺ and dimethyl sulfoxide (DMSO) could enhance the AFB1-degrading activity of B10 laccase. Mutation of the three key metal combined sites of B10 laccase resulted in the loss of AFB1-degrading activity, indicating that these three metal combined sites of B10 laccase play an essential role in the catalytic degradation of AFB1.

The metabolism and biotransformation of AFB1: Key enzymes and pathways

Aflatoxins B₁ (AFB₁) is a hepatoxic compound produced by Aspergillus flavus and Aspergillus parasiticus, seriously threatening food safety and the health of humans and animals. Understanding the metabolism of AFB₁ is important for developing detoxification and intervention strategies. In this review, we summarize the AFB₁ metabolic fates in humans and animals and the key enzymes that metabolize AFB₁, including cytochrome P450s (CYP450s) for AFB₁ bioactivation, glutathione-S-transferases (GSTs) and aflatoxin-aldehyde reductases (AFARs) in detoxification. Furthermore, AFB₁ metabolism in microbes is also summarized. Microorganisms specifically and efficiently transform AFB₁ into less or non-toxic products in an environmental-friendly approach which could be the most desirable detoxification strategy in the future. This review provides a wholistic insight into the metabolism and biotransformation of AFB₁ in various organisms, which also benefits the development of protective strategies in humans and animals.

Invited review: Remediation strategies for mycotoxin control in feed

Mycotoxins are secondary metabolites of different species of fungi. Aflatoxin B1 (AFB1), deoxynivalenol (DON), zearalenone (ZEN) and fumonisin B1 (FB1) are the main mycotoxins contaminating animal feedstuffs. These mycotoxins can primarily induce hepatotoxicity, immunotoxicity, neurotoxicity and nephrotoxicity, consequently cause adverse effects on the health and performance of animals. Therefore, physical, chemical, biological and nutritional regulation approaches have been developed as primary strategies for the decontamination and detoxification of these mycotoxins in the feed industry. Meanwhile, each of these techniques has its drawbacks, including inefficient, costly, or impractically applied on large scale. This review summarized the advantages and disadvantages of the different remediation strategies, as well as updates of the research progress of these strategies for AFB1, DON, ZEN and FB1 control in the feed industry.

Recent technological advances in mechanism, toxicity, and food perspectives of enzyme-mediated aflatoxin degradation

Aflatoxins are carcinogenic secondary metabolites produced by Aspergillus section Flavi that contaminates a wide variety of food and feed products and is responsible for serious health and economic consequences. Fermented foods are prepared with a wide variety of substrates over a long fermentation time and are thus vulnerable to contamination by aflatoxin-producing fungi, leading to the production of aflatoxin B1. The mitigation and control of aflatoxin is currently a prime focus for developing safe aflatoxin-free food. This review summarizes the role of major aflatoxin-degrading enzymes such as laccase, peroxidase, and lactonase, and microorganisms in the context of their application in food. A putative mechanism of enzyme-mediated aflatoxin degradation and toxicity evaluation of the degraded products are also extensively discussed to evaluate the safety of degradation processes for food applications. The review also describes aflatoxin-degrading microorganisms isolated from fermented products and investigates their applicability in food as aflatoxin preventing agents. Furthermore, a summary of recent technological advancements in protein engineering, nanozymes, in silico and statistical optimization approaches are explored to improve the industrial applicability of aflatoxin-degrading enzymes.

Effects of Bacillus subtilis ZJ-2019-1 on Zearalenone Toxicosis in Female Gilts

The purpose of this research was to investigate the toxicity of zearalenone (ZEN) on the growth performance, genital organs, serum hormones, biomarkers, and histopathological changes of female gilts and to evaluate the efficacy of Bacillus subtilis ZJ-2019-1 in alleviating ZEN toxicosis in gilts. Twenty-four female gilts were randomly allocated to four groups with six replicates per group and one gilt per replicate, fed on four feeds prepared previously, which were basic diet (control group, C group), ZEN diet (Z group), Zlb diet (Zlb group) containing B. subtilis ZJ-2019-1 in liquid form, and Zdb diet (Zdb group) containing B. subtilis ZJ-2019-1 in dehydrated form. The results showed that the vulva size and relative weight of reproductive organs had no significant difference in the control group, Zlb group, and Zdb group, but were significantly lower than in the Z group (p < 0.05); the relative weight of the liver was lower in the C group, Zlb group, and Zbd group than in the Z group (0.05 < p < 0.1). The concentration of serum glutamate dehydrogenase (GLDH) was lower, but follicle-stimulating hormone (FSH) was higher in the Z group, Zlb group, and Zdb group than in the Z group (0.05 < p < 0.1). Additionally, serum luteinizing hormone (LH) concentration had no significant difference in the C group, Zlb group, and Zdb group but was significantly lower than in the Z group (p < 0.05); estradiol (E2) was significantly lower in the Zlb group and Zdb group than that in C group, but significantly higher than that in Z group (p < 0.05); PRL was significantly higher in the Zlb group and Zdb group than in the C group, but was significantly lower than in Z group (p < 0.05). ZEN and its reduced metabolites were measured in biological samples after enzymatic hydrolysis of the conjugated forms. The concentration of serum ZEN and its metabolite, α-zeralenol (α-ZOL), had no significant difference in Zlb, Zdb, and control groups but was significantly lower than in the Z group (p < 0.05); urine ZEN and its metabolites, α-ZOL and β-zeralenol (β-ZOL), had no significant difference in Zlb, Zdb, and control groups but was significantly lower than in the Z group (p < 0.05). Cell damages were observed in the liver, uterus, and ovary of gilts in the Z group and alleviated in Zlb and Zdb groups, but the loss of oocytes was irreversible in the ovary. The ZEN-contaminated diet caused serious changes in female hormones and brought harm to the livers and reproductive organs, but B. subtilis ZJ-2019-1 could naturally remove the ZEN significantly, which ameliorated the reproductive impairment in gilts caused by ZEN. The addition of B. subtilis ZJ-2019-1 to ZEN-contaminated feeds could ameliorate the toxic effects effectively, regardless of liquid or dry culture. Therefore, the B. subtilis ZJ-2019-1 strain has great potential industrial applications.

Current and promising strategies to prevent and reduce aflatoxin contamination in grains and food matrices

Mycotoxins are secondary metabolites produced by filamentous fungi that colonise various crops around the world and cause major damage to the agro-industrial sector on a global scale. Considering the estimative of population growth in the next decades, it is of fundamental importance the implementation of practices that help prevent the economics and social impacts of aflatoxin contamination. Even though various approaches have been developed – including physical, chemical and biological approaches – there is not yet one that strikes a balance in terms of safety, food quality and cost, especially when considering large scale application. In this review, we present a compilation of advantages and disadvantages of different strategies for prevention and reduction of aflatoxin contamination. Biological approaches represent the trend in innovations mainly due to their specificity and versatility, since it is possible to consider the utilisation of whole microorganisms, culture supernatants, purified enzymes or even genetic engineering. However, challenges related to improvement of the efficiency of such methods and ensuring safety of treated foods still need to be overcome.

Non-enzymatic Transformation of Aflatoxin B1 by Pseudomonas geniculata m29

Aflatoxin B₁ (AFB₁) is the most harmful mycotoxin produced by filamentous fungi and presents a serious threat to human and animal health. Therefore, it is essential to protect humans and animals from AFB₁-induced acute and chronic toxicity. In this study, Pseudomonas strain m29 having a high efficiency of AFB₁ transformation was isolated from soil. The transformation ratio by m29 was more than 97% within 24 h, and the optimum temperature for transformation was 37°C. Moreover, the AFB₁ transforming activity was mainly attributed to the cell-free supernatant of strain m29. The metabolite that plays a crucial role in AFB₁ transformation is likely 1,2-dimethylhydrazine or 1,1-dimethylhydrazine, as identified by GC-MS and LC-MS analysis. AFB₁ was transformed into a product with molecular formula C₁₇H₁₄O₇. To the best of our knowledge, this is the first study of non-enzymatic AFB₁ transformation by bacteria. Importantly, this AFB₁ transformation mechanism could be universal to various microorganisms.

Detoxification of aflatoxin B1 in broiler chickens by a triple-action feed additive

The aim of this study was to evaluate the detoxification of aflatoxin B₁ (AFB₁) in vitro and in broiler chickens using a triple-action compound mycotoxin detoxifier (CMD). Response surface methodology (RSM) was used to evaluate AFB1 detoxification in artificial gastrointestinal fluid (AGIF) in vitro. The AFB₁-degradation rate was 41.5% (P < .05) when using a compound probiotic (CP) in which the visible counts of Bacillus subtilis, Lactobacillus casein, Enterococcus faecalis and Candida utilis were 1.0 × 10⁵, 1.0 × 10⁵, 1.0 × 10⁷ and 1.0 × 10⁵ CFU/mL, respectively. When CP was combined with 0.1% AFB₁-degrading enzyme to give CPADE, the AFB₁-degradation rate was increased to 55.28% (P < .05). The AFB₁-removal rate was further increased to above 90% when CPADE was combined with 0.03% montmorillonite to make CMD. In vivo, a total of 150 one-day-old Ross broilers were allotted to 3 groups, 5 replications for each group, 10 broilers in each replication. Group A: basal diet, Group B: basal diet with 40 μg/kg AFB₁, Group C: basal diet with 40 μg/kg AFB₁ plus CMD. The feeding experiment period was 21 d. The results showed that broiler growth was increased, and AFB₁ residues in serum, excreta and liver were decreased by CMD addition in broiler diet (P < .05). In conclusion, CMD was able to remove AFB₁ efficiently in vitro and to increase broiler production performance and reduce AFB₁ residues in the chickens.

Co-Cultivation of Two Bacillus Strains for Improved Cell Growth and Enzyme Production to Enhance the Degradation of Aflatoxin B1

Bacillus sp. H16v8 and Bacillus sp. HGD9229 were identified as Aflatoxin B₁ (AFB₁) degrader in nutrient broth after a 12 h incubation at 37 °C. The degradation efficiency of the two-strain supernatant on 100 μg/L AFB₁ was higher than the bacterial cells and cell lysate. Moreover, degradations of AFB₁ were strongly affected by the metal ions in which Cu²⁺ stimulated the degradation and Zn²⁺ inhibited the degradation. The extracellular detoxifying enzymes produced by co-cultivation of two strains were isolated and purified by ultrafiltration. The molecular weight range of the detoxifying enzymes was 20-25 kDa by SDS-PAGE. The co-culture of two strains improved the total cell growth with the enhancement of the total protein content and detoxifying enzyme production. The degradation efficiency of the supernatant from mixed cultures increased by 87.7% and 55.3% compared to Bacillus sp. H16v8 and HGD9229, individually. Moreover, after the degradation of AFB₁, the four products of the lower toxicity were identified by LC-Triple TOF-MS with the two proposed hypothetical degradation pathways.

Myxobacteria and their products: current trends and future perspectives in industrial applications

Myxobacteria belong to a group of bacteria that are known for their well-developed communication system and synchronized or coordinated movement. This typical behavior of myxobacteria is mediated through secondary metabolites. They are capable of producing secondary metabolites belonging to several chemical classes with unique and wide spectrum of bioactivities. It is predominantly significant that myxobacteria specialize in mechanisms of action that are very rare with other producers. Most of the metabolites have been explored for their medical and pharmaceutical values while a lot of them are still unexplored. This review is an attempt to understand the role of potential metabolites produced by myxobacteria in different applications. Different myxobacterial metabolites have demonstrated antibacterial, antifungal, and antiviral properties along with cytotoxic activity against various cell lines. Beside their metabolites, these myxobacteria have also been discussed for better exploitation and implementation in different industrial sectors.

Recombinant Expression of Trametes versicolor Aflatoxin B1-Degrading Enzyme (TV-AFB1D) in Engineering Pichia pastoris GS115 and Application in AFB1 Degradation in AFB1-Contaminated Peanuts

Aflatoxins seriously threaten the health of humans and animals due to their potential carcinogenic properties. Enzymatic degradation approach is an effective and environmentally friendly alternative that involves changing the structure of aflatoxins. In this study, Trametes versicolor aflatoxin B₁-degrading enzyme gene (TV-AFB₁D) was integrated into the genome of Pichia pastoris GS115 by homologous recombination approach. The recombinant TV-AFB₁D was expressed in engineering P. pastoris with a size of approximately 77 kDa under the induction of methanol. The maximum activity of TV-AFB₁D reached 17.5 U/mL after the induction of 0.8% ethanol (v/v) for 84 h at 28 °C. The AFB₁ proportion of 75.9% was degraded using AFB₁ standard sample after catalysis for 12 h. In addition, the AFB₁ proportion was 48.5% using AFB₁-contaminated peanuts after the catalysis for 18 h at 34 °C. The recombinant TV-AFB₁D would have good practical application value in AFB₁ degradation in food crops. This study provides an alternative degrading enzyme for the degradation of AFB₁ in aflatoxin-contaminated grain and feed via enzymatic degradation approach.

Aspergillus flavus Growth Inhibition and Aflatoxin B1 Decontamination by Streptomyces Isolates and Their Metabolites

Aflatoxin B₁ is a potent carcinogen produced by Aspergillus flavus, mainly during grain storage. As pre-harvest methods are insufficient to avoid mycotoxin presence during storage, diverse curative techniques are being investigated for the inhibition of fungal growth and aflatoxin detoxification. Streptomyces spp. represent an alternative as they are a promising source of detoxifying enzymes. Fifty-nine Streptomyces isolates and a Streptomyces griseoviridis strain from the commercial product Mycostop^®, evaluated against Penicillium verrucosum and ochratoxin A during previous work, were screened for their ability to inhibit Aspergillus flavus growth and decrease the aflatoxin amount. The activities of bacterial cells and cell-free extracts (CFEs) from liquid cultures were also evaluated. Fifty-eight isolates were able to inhibit fungal growth during dual culture assays, with a maximal reduction going down to 13% of the control. Aflatoxin-specific production was decreased by all isolates to at least 54% of the control. CFEs were less effective in decreasing fungal growth (down to 40% and 55% for unheated and heated CFEs, respectively) and aflatoxin-specific production, with a few CFEs causing an overproduction of mycotoxins. Nearly all Streptomyces isolates were able to degrade AFB₁ when growing in solid and liquid media. A total degradation of AFB₁ was achieved by Mycostop^® on solid medium, as well as an almost complete degradation by IX20 in liquid medium (6% of the control). CFE maximal degradation went down to 37% of the control for isolate IX09. The search for degradation by-products indicated the presence of a few unknown molecules. The evaluation of residual toxicity of the tested isolates by the SOS chromotest indicated a detoxification of at least 68% of AFB₁’s genotoxicity.

Biological Control and Mitigation of Aflatoxin Contamination in Commodities

Aflatoxins (AFs) are toxic secondary metabolites produced mostly by Aspergillus species. AF contamination entering the feed and food chain has been a crucial long-term issue for veterinarians, medicals, agroindustry experts, and researchers working in this field. Although different (physical, chemical, and biological) technologies have been developed, tested, and employed to mitigate the detrimental effects of mycotoxins, including AFs, universal methods are still not available to reduce AF levels in feed and food in the last decades. Possible biological control by bacteria, yeasts, and fungi, their excretes, the role of the ruminal degradation, pre-harvest biocontrol by competitive exclusion or biofungicides, and post-harvest technologies and practices based on biological agents currently used to alleviate the toxic effects of AFs are collected in this review. Pre-harvest biocontrol technologies can give us the greatest opportunity to reduce AF production on the spot. Together with post-harvest applications of bacteria or fungal cultures, these technologies can help us strictly reduce AF contamination without synthetic chemicals.

Aflatoxin Detoxification Using Microorganisms and Enzymes

Mycotoxin contamination causes significant economic loss to food and feed industries and seriously threatens human health. Aflatoxins (AFs) are one of the most harmful mycotoxins, which are produced by Aspergillus flavus, Aspergillus parasiticus, and other fungi that are commonly found in the production and preservation of grain and feed. AFs can cause harm to animal and human health due to their toxic (carcinogenic, teratogenic, and mutagenic) effects. How to remove AF has become a major problem: biological methods cause no contamination, have high specificity, and work at high temperature, affording environmental protection. In the present research, microorganisms with detoxification effects researched in recent years are reviewed, the detoxification mechanism of microbes on AFs, the safety of degrading enzymes and reaction products formed in the degradation process, and the application of microorganisms as detoxification strategies for AFs were investigated. One of the main aims of the work is to provide a reliable reference strategy for biological detoxification of AFs.

Degradation and Detoxification of Aflatoxin B1 by Tea-Derived Aspergillus niger RAF106

Microbial degradation is an effective and attractive method for eliminating aflatoxin B1 (AFB1), which is severely toxic to humans and animals. In this study, Aspergillus niger RAF106 could effectively degrade AFB1 when cultivated in Sabouraud dextrose broth (SDB) with contents of AFB1 ranging from 0.1 to 4 μg/mL. Treatment with yeast extract as a nitrogen source stimulated the degradation, but treatment with NaNO₃ and NaNO₂ as nitrogen sources and lactose and sucrose as carbon sources suppressed the degradation. Moreover, A. niger RAF106 still degraded AFB1 at initial pH values that ranged from 4 to 10 and at cultivation temperatures that ranged from 25 to 45 °C. In addition, intracellular enzymes or proteins with excellent thermotolerance were verified as being able to degrade AFB1 into metabolites with low or no mutagenicity. Furthermore, genomic sequence analysis indicated that the fungus was considered to be safe owing to the absence of virulence genes and the gene clusters for the synthesis of mycotoxins. These results indicate that A. niger RAF106 and its intracellular enzymes or proteins have a promising potential to be applied commercially in the processing and industry of food and feed to detoxify AFB1.

Novel strategies for degradation of aflatoxins in food and feed: A review

Aflatoxins are toxic secondary metabolites mainly produced by Aspergillus fungi, posing high carcinogenic potency in humans and animals. Dietary exposure to aflatoxins is a global problem in both developed and developing countries especially where there is poor regulation of their levels in food and feed. Thus, academics have been striving over the decades to develop effective strategies for degrading aflatoxins in food and feed. These strategies are technologically diverse and based on physical, chemical, or biological principles. This review summarizes the recent progress on novel aflatoxin degradation strategies including irradiation, cold plasma, ozone, electrolyzed oxidizing water, organic acids, natural plant extracts, microorganisms and enzymes. A clear understanding of the detoxification efficiency, mechanism of action, degradation products, application potential and current limitations of these methods is presented. In addition, the development and future perspective of nanozymes in aflatoxins degradation are introduced.

Biotransformation of aflatoxin B1 by Lactobacillus helviticus FAM22155 in wheat bran by solid-state fermentation

Lactobacillus helveticus FAM22155 was the most efficient among five lactic acid bacteria at removing aflatoxin B₁ (AFB₁) during solid-state fermentation on wheat bran substrate. The mechanism of removal was explored by comparing different fermentation modes. Liquid fermentation had little effect on the breakdown of AFB₁. However, a protein extract from the fermented bran was equally effective at degrading aflatoxin B₁ as living cell digestion. After treatment with heat and protease K, the degrading capacity of the protein extract was significantly reduced. Taken together, the observed biotransformation of AFB₁ was mainly associated with proteins produced during bran fermentation. Four products of U-[¹³C₁₇]-AFB₁ were found by mass spectrometry, including Ⅱ-1 (C₁₁H₁₀O₄), Ⅱ-2 (C₁₁H₁₀O₄), III (C₁₅H₁₂O₅), and IV (C₁₄H₁₀O₄). These products all lack the lactone ring indicating lower toxicity than aflatoxin B₁.

Statistical optimization of cultural variables for enzymatic degradation of aflatoxin B1 by Panus neostrigosus

The aim of this study is to determine the best aflatoxin B₁ degradation conditions which was optimized using a combination of the Plackett-Burman and Box-Behnken methods with Panus neostrigosus culture filtrate. Panus neostrigosus was grown in a modified Kirk Broth medium to determine optimal degradation conditions. As a result, aflatoxin B₁ was degraded under varying culture conditions. The Plackett-Burman method was designed after sixteen different experiments with fifteen variables. The three most effective variables (Sucrose, yeast extract, wheat bran) were chosen for the Box-Behnken methodology. The aflatoxin B₁ degradation rate was 49% in just 1 h exposure to culture filtrate which was obtained under optimal growth conditions; (g-ml/L) sucrose 10, yeast extract 3, wheat bran 3, soytone 5, KH₂PO₄ 2, MgSO₄.7H₂O 0.5, CaCl₂.H₂O 0.1, ammonium tartrate 2, trace element solution 10; 28 °C of incubation temperature, medium pH 5, 7.5% inoculum rate, 125 rpm of agitation speed, and a twelve-day incubation period. The SDS-PAGE studies show that the enzyme responsible for AFB₁ degradation has 38 kDa molecular weight and has no laccase or MnP activity. To the best of our knowledge, this is the first report for AFB₁ degradation by Panus neostrigosus.

A New Laccase of Lac 2 from the White Rot Fungus Cerrena unicolor 6884 and Lac 2-Mediated Degradation of Aflatoxin B1

Aflatoxin B₁ (AFB₁) is a known toxic human carcinogen and can be detoxified by laccases, which are multicopper oxidases that convert several environmental pollutants and toxins. In this study, a new laccase that could catalyze AFB₁ degradation was purified and identified from the white-rot fungus Cerrena unicolor 6884. The laccase was purified using (NH₄)₂SO₄ precipitation and anion exchange chromatography, and then identified as Lac 2 through zymogram and UHPLC-MS/MS based on the Illumina transcriptome analysis of C. unicolor 6884. Six putative laccase protein sequences were obtained via functional annotation. The lac 2 cDNA encoding a full-length protein of 512 amino acids was cloned and sequenced to expand the fungus laccase gene library for AFB₁ detoxification. AFB₁ degradation by Lac 2 was conducted in vitro at pH 7.0 and 45 °C for 24 h. The half-life of AFB₁ degradation catalyzed by Lac 2 was 5.16 h. Acetosyringone (AS), Syrinagaldehyde (SA) and [2,2' -azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS) at 1 mM concentration seemed to be similar mediators for strongly enhancing AFB₁ degradation by Lac 2. The product of AFB₁ degradation catalyzed by Lac 2 was traced and identified to be Aflatoxin Q₁ (AFQ₁) based on mass spectrometry data. These findings are promising for a possible application of Lac 2 as a new aflatoxin oxidase in degrading AFB₁ present in food and feeds.

Mycotoxin contamination and control strategy in human, domestic animal and poultry: A review

Mycotoxins are secondary metabolites produced mainly by fungi belonging to the genera Aspergillus, Fusarium, Penicillium, Claviceps, and Alternaria that contaminate basic food products throughout the world, where developing countries are becoming predominantly affected. Currently, more than 500 mycotoxins are reported in which the most important concern to public health and agriculture include AFB1, OTA, TCTs (especially DON, T-2, HT-2), FB1, ZEN, PAT, CT, and EAs. The presence of mycotoxin in significant quantities poses health risks varying from allergic reactions to death on both humans and animals. This review brings attention to the present status of mycotoxin contamination of food products and recommended control strategies for mycotoxin mitigation. Humans are exposed to mycotoxins directly through the consumption of contaminated foods while, indirectly through carryover of toxins and their metabolites into animal tissues, milk, meat and eggs after ingestion of contaminated feeds. Pre-harvest (field) control of mycotoxin production and post-harvest (storage) mitigation of contamination represent the most effective approach to limit mycotoxins in food and feed. Compared with chemical and physical approaches, biological detoxification methods regarding biotransformation of mycotoxins into less toxic metabolites, are generally more unique, productive and eco-friendly. Along with the biological detoxification method, genetic improvement and application of nanotechnology show tremendous potential in reducing mycotoxin production thereby improving food safety and food quality for extended shelf life. This review will primarily describe the latest developments in the formation and detoxification of the most important mycotoxins by biological degradation and other alternative approaches, thereby reducing the potential adverse effects of mycotoxins.

Control of aflatoxin M1 in milk by novel methods: A review

Aflatoxin M₁ (AFM₁) in milk and milk products has been recognised as an issue for over 30 years. Controlling AFM₁ in milk is important to protect human health and trade. Preventing contamination by avoiding fungal contamination of cattle feed is the best method of control, however this is hard to avoid in some countries. Treating milk containing AFM₁ is an alternative control measure, however, there is no single approved method. The challenge is to select a treatment method that is effective but does not affect the organoleptic quality of milk. This study reviews the strategies for degrading AFM₁ in milk including yeast, lactic acid bacteria, enzyme, peroxide, ozone, UV light and cold plasma. This review compares the efficacy, influencing factors, (possible) mechanisms of activity, advantages, limitations and potential future trends of these methods and provides some recommendations for the treatment of milk to reduce the risk of AFM₁ contamination.

Fermentation for tailoring the technological and health related functionality of food products

Fermented foods are experiencing a resurgence due to the consumers' growing interest in foods that are natural and health promoting. Microbial fermentation is a biotechnological process which transforms food raw materials into palatable, nutritious and healthy food products. Fermentation imparts unique aroma, flavor and texture to food, improves digestibility, degrades anti-nutritional factors, toxins and allergens, converts phytochemicals such as polyphenols into more bioactive and bioavailable forms, and enriches the nutritional quality of food. Fermentation also modifies the physical functional properties of food materials, rendering them differentiated ingredients for use in formulated foods. The science of fermentation and the technological and health functionality of fermented foods is reviewed considering the growing interest worldwide in fermented foods and beverages and the huge potential of the technology for reducing food loss and improving nutritional food security.

Enzymes for Detoxification of Various Mycotoxins: Origins and Mechanisms of Catalytic Action

Mycotoxins are highly dangerous natural compounds produced by various fungi. Enzymatic transformation seems to be the most promising method for detoxification of mycotoxins. This review summarizes current information on enzymes of different classes to convert various mycotoxins. An in-depth analysis of 11 key enzyme mechanisms towards dozens of major mycotoxins was realized. Additionally, molecular docking of mycotoxins to enzymes' active centers was carried out to clarify some of these catalytic mechanisms. Analyzing protein homologues from various organisms (plants, animals, fungi, and bacteria), the prevalence and availability of natural sources of active biocatalysts with a high practical potential is discussed. The importance of multifunctional enzyme combinations for detoxification of mycotoxins is posed.

Presence of aiiA homologue genes encoding for N-Acyl homoserine lactone-degrading enzyme in aflatoxin B1-decontaminating Bacillus strains with potential use as feed additives

Microbial degradation of aflatoxins (AFs) is an alternative to the use of mycotoxin binders. The lactone ring is a possible target for microbial enzymes and its cleavage reduces AFs toxicity. The aim of this study was to isolate and identify Bacillus strains able to degrade AFB₁ to less toxic metabolites and to identify aiiA genes encoding for N-acyl-homoserine lactone (AHL) lactonase to possibly correlate detoxification with the production of this enzyme. Eleven soilborne Bacillus strains were isolated and identified by MALDI-TOF MS. Ten cultures and eight cell free culture supernatants (CFCS) were able to significantly (P < 0.05) degrade 27.78-79.78% AFB₁. Cell lysates were also able to degrade AFB₁ (P < 0.05). Exposure to 70 and 80 °C did not affect enzyme activity. Aflatoxin B₁ toxicity towards Artemia salina was reduced after degradation by each of the Bacillus strains. B. subtilis RC1B, B. cereus RC1C and B. mojavensis RC3B, amplified a fragment of 753 pb corresponding to the aiiA gene encoding for AHL lactonase. AFB₁ degradation by the strains tested was due to the extracellular and intracellular enzymes. If demonstrated to be safe, these could be used to detoxify AFB₁ in contaminated food or feed.

Effective Biodegradation of Aflatoxin B1 Using the Bacillus licheniformis (BL010) Strain

Aflatoxin B1 (AFB1), a pollutant of agricultural products, has attracted considerable attention in recent years, due to its potential impact on health. In the present study, Bacillus licheniformis (BL010) was demonstrated to efficiently degrade AFB1, reducing over 89.1% of the toxin content within 120 h. A crude enzyme solution of BL010 exhibited the highest degradation level (97.3%) after three induction periods. However, uninduced BL010 bacteria was not capable of reducing AFB1. Furthermore, high performance liquid chromatography (HPLC) analysis showed that while a cell-free extract caused a significant decrease in AFB1 content (93.6%, p < 0.05), cell culture fluid treatment did not significantly degrade AFB1. The biotransformation products of AFB1 were detected and further identified by quadrupole time-of-flight liquid chromatography⁻mass spectrometry (LC-Q-TOF/MS); these corresponded to a molecular formula of C12H14O₄. A sequence analysis of whole BL010 genes with a bioinformatics approach identified the secondary structures of two degrading enzymes (Chia010 and Lac010), providing an important basis for subsequent homology modeling and functional predictions.

Purification and identification of an aflatoxin B1 degradation enzyme from Pantoea sp. T6

Aflatoxin B₁ (AFB₁) is a secondary metabolite produced by Aspergillus flavus and other fungi. Soil, crops, food, feed, etc. were susceptible to aflatoxin B₁ contamination, which caused adverse economic and health consequences. It is necessary to search for microorganisms or microbial enzymes that can degrade AFB₁. The degradation activity of AFB₁ by cell-free supernatant (68.30%) of isolate Pantoea sp. T6 was significantly higher (P < 0.05) than viable bacterial cells (4.87%) and intracellular cell extracts (3.68%). The supernatant's AFB₁ degradation activity was reduced from 68.30% to 5.33% in treatment with protease K and sodium dodecyl sulphate (SDS). An extracellular enzyme from the supernatant was secreted by Pantoea sp. T6 and was named as Pantoea aflatoxin degradation enzyme (PADE), which was obtained using Diethylaminoethanol (DEAE)-Sepharose chromatography. PADE was further purified by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The PADE, outer membrane protein A, was identified by mass spectrometry and molecular mass was 38180.1Da. The optimum temperature and pH for the reaction of PADE with AFB₁ were 40 °C and 7.0, respectively. These finding showing that the PADE, which was isolated from the supernatant of Pantoea sp. T6, has the ability to degrade AFB₁, and may have potential application for aflatoxin B₁ reduction in the food and feed industry.

Aflatoxin B1 degradation by salt tolerant Tetragenococcus halophilus CGMCC 3792

This study explores aflatoxin B1 (AFB1) degradation by salt tolerant Tetragenococcus halophilus CGMCC 3792 (T. halophilus CGMCC 3792). Six non-toxic degradation products of AFB1 were identified by liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS), including m/z 243.06 (C14H10O4), 361.09 (C18H16O8), 229.09 (C14H12O3), 277.14 (C16H20O4), 217.12 (C14H16O2), 221.15 (C14H20O2). Two pathways were proposed based on molecular formulas and MS/MS spectra, and the final degradation product was m/z 221.15 (C14H20O2). The degradation ratio of active cell component (66%) and intracellular component (57%) was significantly higher than extracellular component (14%). AFB1 degradation ratio of intracellular component, initially at around 60%, was decreased to 32% after proteinase K treatment, and to 7% after heating, to 9% after proteinase K plus SDS treatment, and to 16% after TFA treatment. It suggests that the AFB1 removal mainly resulted from enzyme biodegradation. The degradation ratio was 92% in AFB1 polluted soy sauce mash. The high degradation ratio of AFB1 by T. halophilus CGMCC 3792 indicates its great potential for application in oriental fermentation condiment process.

Effect of probiotic supplement on aflatoxicosis and gene expression in the liver of broiler chicken

The present study aimed to investigate the toxic effect of aflatoxin B1 (AFB1) and the effectiveness of a biological mycotoxin binder (Nutritox^®) in detoxifying aflatoxicosis. Ninety one-day-old chicks were chosen and divided into 3 groups. The first group received standard basal diet only, the second group received a basal diet with AFB1 (0.25 mg/kg diet), and the third group received a basal diet with AFB1 (0.25 mg/kg diet) and Nutritox^® (1 kg/ton diet). AFB1 feed contamination significantly reduced growth performance and deteriorated FCR. Moreover, it significantly increased serum AST, ALT, and malondialdehyde and significantly decreased serum total protein, albumin, globulin, SOD, CAT activities and glutathione peroxidase gene expression as well. Aflatoxin residues were detected in the liver tissues. Furthermore, the liver and kidney of AFB1 treated group showed pathological changes. The supplementation of Nutritox^® significantly reduced aflatoxin levels in the liver and counteracted the negative effects of AFB1.