Aflatoxin binding efficiency of Saccharomyces cerevisiae mannoprotein in contaminated pistachio nuts

Adsorptive removal of aflatoxin B1 via spore protein from Aspergillus luchuensis YZ-1

Aflatoxin B1 (AFB1) is the most toxic mycotoxin commonly found in the environment. Finding efficient and environmentally friendly ways to remove AFB1 is critical. In this study, Aspergillus luchuensis YZ-1 demonstrated a potent ability to adsorb AFB1 for the first time, and the binding of AFB1 to YZ-1 is highly stable. Spores exhibited higher adsorption efficiency than mycelia, adsorbing approximately 95 % of AFB1 within 15 min. The spores were comprehensively characterized using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and atomic force microscopy. Various adsorption kinetic models (pseudo-first and pseudo-second order), adsorption isotherm models (Freundlich and Langmuir), Fourier transform infrared, and X-ray photoelectron spectroscopy were used to investigate the adsorption properties and mechanisms. The adsorption capacity of spores decreased with heating, urea, and SDS treatments, indicating that spore proteins may be the primary substance for AFB1 adsorption. Subsequent experiments showed that proteins with molecular weights greater than 50 kDa played a key role in the adsorption. Additionally, the spores possess excellent storage properties and are valuable for adsorbing AFB1 from vegetable oils. Therefore, the YZ-1 spores hold promise for development into a novel biosorbent for AFB1 removal.

The synergistic effect of titanium dioxide nanoparticles and yeast isolated from fermented foods in reduction of aflatoxin B1

The presence of aflatoxins in food products can lead to health risks in human societies. Therefore, in the present study, the effect of yeast strains isolated from fermented products and titanium dioxide nanoparticles (TiO2-NPs) was studied on aflatoxin reduction. Yeast strains were isolated from fermented products such as sweet fruits and dairy products and identified using biochemical, ascospore (testing by culture medium optimization V8 which is called V8NLF), and molecular methods. The probiotic activity of four selected yeasts was evaluated. Then, the effect of selected yeast isolates and TiO2-NPs on reducing aflatoxin B1 (AFB1) in the medium was studied by measuring AFB1 using ELISA and HPLC. The results of biochemical and molecular identification experiments indicate that the selected strain (Y1) is Saccharomyces cerevisiae. The selected strains showed good tolerance to different concentrations of bile salt, pH, and NaCl, indicating appropriate probiotic activity. It also showed antimicrobial activity against Escherichia coli, Shigella dysenteriae, and Salmonella typhimurium. Selected strain and TiO2-NPs showed AFB1 reducing activity in the medium and when combined, showed synergistic effects in reducing AFB1. TiO2-NPs in combination with selected yeast strains have a high ability to remove AFB1 from the medium and, therefore, can be used for future studies.

Probiotic-Based Optimization of Pistachio Paste Production and Detoxification of Aflatoxin B1 Using Bifidobacterium lactis

Pistachio paste is very popular for breakfast or supper thanks to its desirable taste, flavor, and texture. One of the hazards that are directly related to agricultural practices, processing, storage, and transportation of pistachios and the byproducts is aflatoxin, which can cause irreversible effects on the consumer. Probiotics are one of the most effective and safe methods to reduce aflatoxins. The variables under study were temperature and time, aflatoxin concentration, and probiotic content. In total, 30 treatments were determined through the rotatable central composite design. This is the first and most comprehensive study to optimize the production of probiotic pistachio paste and investigate the detoxification effects of aflatoxin B1 using Bifidobacterium lactis with six treatments and three replications in the pistachio paste matrix. In simple terms, it is possible to remove a higher percentage of toxins by increasing the number of microorganisms and decreasing the toxin level. The highest aflatoxin B1 reduction was observed in pistachio paste with aflatoxin B1 contamination of (19.7039 ng/g), which was spiked with Bifidobacterium lactis (109 CFU/g) and then stored at 25°C for 26.1853 days (aflatoxin B1: 8.00007 ng/g = 59.4% reduction), which is consistent with the permissible limits of the Iran National Standards Organization and the European Commission Regulation. The results showed a significant reduction in the aflatoxin B1 level in pistachio paste. The probiotics reduced aflatoxin B1 contamination to a permissible level. This is an important, safe, and effective solution, and unlike other methods, it increases the nutritional value of the product.

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.

In vitro mycotoxin binding capacities of clays, glucomannan and their combinations

Clays, glucomannans and their combinations are widely used to bind mycotoxins in contaminated feeds to reduce their toxic effects on animals. In the present study, the binding abilities of clinoptilolite, sepiolite, bentonite, and montmorillonite, glucomannan, and four commercial TB products (P1, P2, C1 and C2) were investigated in vitro for their binding effects on seven different mycotoxins (AF, aflatoxin; OTA, ochratoxin; ZEA, zearalenone; DON, deoxynivalenol; FUM, fumonisin; T-2 toxin, and HT-2 toxin) in medium at pH 3.0 and 6.8. The clays were observed to bind AF, DON, and OTA at the following levels: clinoptilolite on AF at 72-90%, on DON at 61-68%, and on OTA at 52-62%; sepiolite on AF at 92-98%, on DON at 36-68%, and on OTA at 53-55%; bentonite on AF at 88-95%, on DON at 23-73%, and on OTA at 54-56%, and montmorillonite on AF at 74-80%, on DON at 46-68%, and on OTA at 54-55%. We also observed that these clays bound ZEA, FUM, T-2, and HT-2 at 25-45%. Glucomannan bound AF at a high rate (85-96%); however, bound DON at 31-56% and OTA at 54-55%, and other mycotoxins at 25-43%. Although P1, which consisted of clay combinations, bound AF and OTA at high rates, it bound DON, FUM, ZEA, T-2, and HT-2 at medium rates. P2, to which glucomannan was added to the clay combination, was observed to have the ability to bind OTA, FUM, and T-2 at ∼15-20% more than P1. When similar commercial products were compared, P2 provided ∼>10% adsorption of AF, 20% of OTA and FUM, and 5% of T-2 than C1, while similar binding ability of these two products were observed on the other toxins.

In vitro and in vivo capacity of yeast-based products to bind to aflatoxins B1 and M1 in media and foodstuffs: A systematic review and meta-analysis

The aflatoxins are hepatotoxic and carcinogenic metabolites produced by Aspergillus species during growth on crop products. In this regard, a systematic review to collect the quantitative data regarding the in vitro capacity of yeasts-based products to bind to aflatoxin B₁ (AFB₁) and/or aflatoxin M₁ (AFM₁) was performed. After screening, 31 articles which met the inclusion criteria was included and then the pooled decontamination of aflatoxins in the defined subgroups (the type of foods, pH, contact time, temperature, yeast species, and aflatoxin type) was calculated by the random effect model (REM). The overall binding capacity (BC) of aflatoxins by yeast was 52.05% (95%CI: 49.01-55.10), while the lowest and highest aflatoxins' BC were associated with Yeast Extract Peptone (2.79%) and ruminal fluid + artificial saliva (96.21%), respectively. Regarding the contact time, temperature, pH and type of aflatoxins subgroups, the binding percentages varied from 50.83% (>300 min) to 52.66% (1-300 min), 50.71% (0-40 °C) to 88.39% (>40 °C), 43.03% (pH: 3.1-6) to 44.56% (pH: 1-3) and 59.35% (pH > 6), and 48.47% (AFB₁) to 69.03% AFM₁, respectively. The lowest and highest aflatoxins' BC was related to C. fabianii (18.45%) and Z. rouxii (86.40%), respectively. The results of this study showed that variables such as temperature, yeast, pH and aflatoxin type can be considered as the effective factors in aflatoxin decontamination.

Protective effects of mannan/β-glucans from yeast cell wall on the deoxyniyalenol-induced oxidative stress and autophagy in IPEC-J2 cells

The aim of this study was to investigate the effects of biomacromolecules mannan/β-glucans from yeast cell wall (BYCW) to alleviate Deoxynivalenol(DON)-induced injury. Considering that DON has strong oxidizing effect and stimulates autophagy and apoptosis, we examined the effects of BYCW on consequent oxidative stress damage indicators, cells autophagy and apoptosis induced by DON using the porcine jejunum epithelial cell lines (IPEC-J2) as a cell culture model. The results showed that application of BYCW could reverse the decrease of cell viability by DON significantly, and suppress the levels of tumor necrosis factor-α (TNF-α) and interleukin-8 and -6 (IL-8 and IL-6), except IL-1β. Further experiments revealed that BYCW treatment counteracted the DON-induced down-regulation of intracellular glutathione (GSH) and up-regulation of reactive oxygen species (ROS) and malondialdehyde (MDA). Through western blot analysis, we observed that BYCW treatment was able to down-regulate the expression of autophagy protein LC3-II and up-regulate the expression of P62 protein against DON, which suggested that autophagy induced by DON may be suppressed. Altogether, these results indicated a potential ability of supplementation of BYCW to improve cell growth and metabolism as well as the preventive properties of BYCW against the DON-induced cell damage by activating antioxidant system.