Adsorption of zearalenone by native Brazilian yeasts for feed applications

Grape pomace (pulp and skins) was investigated as a new biosorbent for removing mycotoxins from liquid media. In vitro adsorption experiments showed that the pomace obtained from Primitivo grapes is able to sequester rapidly and simultaneously different mycotoxins. Aflatoxin B1 (AFB1) was the most adsorbed mycotoxin followed by zearalenone (ZEA), ochratoxin A (OTA), and fumonisin B1 (FB1), whereas the adsorption of deoxynivalenol (DON) was negligible. AFB1 and ZEA adsorptions were not affected by changing pH values in the pH 3-8 range, whereas OTA and FB1 adsorptions were significantly affected by pH. Equilibrium adsorption isotherms obtained at different temperatures (5-70 °C) and pH values (3 and 7) were modeled and evaluated using the Freundlich, Langmuir, Sips, and Hill models. The goodness of the fits and the parameters involved in the adsorption mechanism were calculated by the nonlinear regression analysis method. The best-fitting models to describe AFB1, ZEA, and OTA adsorption by grape pomace were the Sips, Langmuir, and Freundlich models, respectively. The Langmuir and Sips models were the best models for FB1 adsorption at pH 7 and 3, respectively. The theoretical maximum adsorption capacities (mmol/kg dried pomace) calculated at pH 7 and 3 decreased in the following order: AFB1 (15.0 and 15.1) > ZEA (8.6 and 8.3) > OTA (6.3-6.9) > FB1 (2.2 and 0.4). Single- and multi-mycotoxin adsorption isotherms showed that toxin adsorption is not affected by the simultaneous presence of different mycotoxins in the liquid medium. The profiles of adsorption isotherms obtained at different temperatures and pH and the thermodynamic parameters (ΔG°, ΔH°, ΔS°) suggest that mycotoxin adsorption is an exothermic and spontaneous process, which involves physisorption weak associations. Hydrophobic interactions may be associated with AFB1 and ZEA adsorption, whereas polar noncovalent interactions may be associated with OTA and FB1 adsorption. In conclusion, this study suggests that biosorption of mycotoxins onto grape pomace may be a reasonably low-cost decontamination method.

Zearalenone (ZEA) adsorption by a mixture of organic (yeast cell wall) and inorganic (activated charcoal) adsorbents was evaluated by an incomplete Box Behnken (33) statistical design with a quintuplicate at the central point. The variables analysed were different ratios of adsorbents (yeast cell wall and activated charcoal) at 100:0, 87.5:12.5 and 75:25, pH (3.0, 4.5 and 6.0) and ZEA concentrations (300, 750 and 1,200 ng/ml). The adsorbent mixture at 75:25 showed higher efficiency for ZEA adsorption (≯96.1%) than the 87.5:12.5 ratio (81.3 to 93.7%) and with the pure yeast cell wall (78.1 to 55.7%). The significant variables were the ratio of adsorbent mixture and ZEA concentration. The effect of pH was not significant (P=0.05), indicating that the binding between ZEA and the adsorbent would be stable at different pH (3.0, 4.5 and 6.0). The quadratic model obtained by the Box Behnken (33) design can be used for predictive purposes, because it showed a non-significant deviation (P=49.54%) and a good correlation coefficient (R2=0.98), suggesting that the ZEA adsorption would be maximum (100%) when the adsorbent mixture is set at 75:25 and the ZEA concentration at 300 ng/ml. Although the predictive model showed that an increase in adsorption efficiency could occur in a smaller ZEA concentration (300 ng/ml), the mixture at the 75:25 ratio presented high efficiency (≯98%) in adsorption when high ZEA concentrations were used (1,200 ng/ml), indicating that these mixtures would be able to adsorb a wide range of ZEA concentrations. Therefore, this mixture of yeast cell wall and activated charcoal adsorbents at 75:25 might be a candidate for furtherin vivotesting.

In the present study, activated carbon (AC) was derived from seed shells of Jatropha curcas and applied to decontaminate the zearalenone (ZEA) mycotoxin. The AC of J. curcas (ACJC) was prepared by ZnCl2 chemical activation method and its crystalline structure was determined by X-ray diffraction analysis. The crystalline graphitic nature of ACJC was confirmed from the Raman spectroscopy. Scanning electron microscope showed the porous surface morphology of the ACJC surface with high pore density and presence of elemental carbon was identified from the energy dispersive X-ray analysis. From Brunauer–Emmett–Teller (BET) analysis, SBET, micropore area, and average pore diameter of ACJC were calculated as 822.78 (m2/g), 255.36 (m2/g), and 8.5980 (Å), respectively. The adsorption of ZEA by ACJC was accomplished with varying contact time, concentration of ZEA and ACJC, and pH of media. The ACJC has adsorbed the ZEA over a short period of time and adsorption of ZEA was dependent on the dose of ACJC. The effect of different pH on adsorption of ZEA by ACJC was not much effective. Desorption studies confirmed that adsorption of ZEA by ACJC was stable. The adsorption isotherm of ZEA by ACJC was well fitted with Langmuir model rather than Freundlich and concluded the homogeneous process of sorption. The maximum adsorption of ZEA by ACJC was detected as 23.14 μg/mg. Finally, adsorption property of ACJC was utilized to establish ACJC as an antidote against ZEA-induced toxicity under in vitro in neuro-2a cells. The percentage of live cells was high in cells treated together with a combination of ZEA and ACJC compared to ZEA treated cells. In a similar way, ΔΨM was not dropped in cells exposed to combination of ACJC and ZEA compared to ZEA treated cells. Furthermore, cells treated with a combination of ZEA and ACJC exhibited lower level of intracellular reactive oxygen species and caspase-3 compared to ZEA treated cells. These in vitro studies concluded that ACJC has successfully protected the cells from ZEA-induced toxicity by lowering the availability of ZEA in media as a result of adsorption of ZEA. The study concluded that ACJC was a potent decontaminating agent for ZEA and could be used as an antidote against ZEA-induced toxicity.

Ochratoxin A and zearalenone adsorption by the natural zeolite treated with benzalkonium chloride

Zearalenone (ZEN), is a secondary metabolite with estrogenic properties, is produced by several Fusarium species that colonize cereal grains such as corn, oats, barley, wheat, and grain sorghum in the field and in storage. Because of the toxic effects of ZEN which cause significant human and animal diseases and significant economic losses worldwide, its removal from food samples is very important. In this study, the applicability of natural zeolite, Clinoptilolite (CLN), and organo-clinoptilolites modified with the quaternary ammonium salts tetramethylammonium bromide (TMA) for the short-chain organo-zeolite and octadecyl trimethyl ammonium bromide (ODTMA) for the long-chain organo-zeolite, has been investigated for the adsorption and preconcentration of Zearalenone (ZEN) from beer solutions. In the batch experiments, ZEN was quantitatively adsorbed (~100%) at the pH range of 1.1–9.0 by ODTMAClinoptilolite (ODTMA-CLN). As for CLN and TMA-Clinoptilolite (TMA-CLN), ZEN adsorptions were about 100% at the pH range 1.1-4.5 and 70% at pH range 4.8-7.0. The adsorption of ZEN was investigated in terms of the Langmuir and Freundlich isotherm models and the Freundlich isotherm model was found as being adequate to describe the adsorption for all adsorbents. The proposed methodology was applied to the beer samples for adsorption and preconcentration of ZEN, the recoveries found for CLN and TMA-CLN were not sufficient (44.0 and 56.7%, respectively), but the recovery carried out with ODTMA-CLN was high (89.5%).

Cross-linked chitosan polymers as generic adsorbents for simultaneous adsorption of multiple mycotoxins

In vitro adsorption of zearalenone by cetyltrimethyl ammonium bromide-modified montmorillonite nanocomposites

Evaluation of nonionic surfactant modified montmorillonite as mycotoxins adsorbent for aflatoxin B1 and zearalenone

Adsorption of the mycotoxin zearalenone by clinoptilolite and phillipsite zeolites treated with cetylpyridinium surfactant

The purpose of the present study was to evaluate the effect of pH on the ultrastructure of the conidial wall of dead conidia harvested from the non-toxicogenicAspergillus niger aggregate strain RC084 and its relationship to zearalenone (ZEA) adsorption capacity. Moreover, mathematical models were applied to explain the interaction between conidia and ZEA absorbance. A ZEA adsorption test was performed using a concentration of 1×107 dead conidia/ml at pH 2 and 6 at 37 °C for 30 min. Unbound ZEA was quantified by high-pressure liquid chromatography. The ZEA adsorption was strongly dependent on the pH of the medium; the highest values were 2.2×10-6 μg ZEA/conidia at pH 6. Isotherms representing the amount of bound ZEA as a function of ZEA concentration in equilibrium after adsorption have typical S- or L-shapes. The experimental data could be fitted to the Frumkin-Fowler-Guggenheim (FFG) and Hill theoretical models. The ultrastructure of the conidial wall was studied by infrared spectroscopy (IR) and transmission electron microscopy (TEM). The representative IR spectra showed that pH did not produce significant changes in the different chemical groups. However, ultrastructure studies by TEM detected considerable changes in the organisation of the conidial wall. This is the first study showing that the loss of the outermost electron dense layer, responsible for the ornamentations on the conidial surface. Adsorption is favoured at pH 6".

Grains of the three differentially Fusarium-susceptible winter wheat cultivars “Ritmo” (highly susceptible), “Inspiration” (moderately to highly susceptible) and “Dekan” (lowly to moderately susceptible) from up to eight trial locations in Schleswig-Holstein (Northern Germany) and maize-free crop rotations were analysed for their mycotoxin concentration from 2008 to 2017 (“Inspiration” and “Dekan” since 2012). The deoxynivalenol (DON) and zearalenone (ZEA) concentrations of wheat grain samples differed significantly between individual years and within each year between the trial locations due to weather conditions during flowering. Significant relationships were found between the two weather variables cumulative precipitation (added up by all daily cumulative precipitation) and average temperature (averaged for all daily means of temperature) during the period of wheat flowering and DON and ZEA concentrations in wheat grain at harvest. These relationships were determined for “Ritmo” from 2008 to 2014 ( $$R^{2}_{{{\text{adj}} .}}$$ = 0.81 for DON; $$R^{2}_{{{\text{adj}} .}}$$ = 0.75 for ZEA) and for both “Inspiration” ( $$R^{2}_{{{\text{adj}} .}}$$ = 0.84 for DON; $$R^{2}_{{{\text{adj}} .}}$$ = 0.82 for ZEA) and “Dekan” ( $$R^{2}_{{{\text{adj}} .}}$$ = 0.78 for DON; $$R^{2}_{{{\text{adj}} .}}$$ = 0.77 for ZEA) from 2012 to 2016. Based on this, multiple regression models were developed for the three cultivars for the prediction of DON and ZEA contamination in wheat grain: model 1 = highly susceptible; model 2 = moderately to highly susceptible; model 3 = lowly to moderately susceptible. The models included the covariates cumulative precipitation and average temperature during wheat flowering and the interaction term of precipitation and temperature. The predictive power of the three models was evaluated with data not utilized in the development of the models, i.e. weather conditions during wheat flowering and DON and ZEA concentrations in wheat grain at harvest at the same trial locations in the years 2015 to 2017 for model 1 and in 2017 for model 2 and model 3. The models showed a high predictive power by regressing observed versus predicted values (model 1: R2 = 0.89 for DON, R2 = 0.91 for ZEA; model 2: R2 = 0.91 for DON, R2 = 0.84 for ZEA; model 3: R2 = 0.86 for DON, R2 = 0.89 for ZEA). Model 1 predicted correctly whether the concentrations of DON and ZEA were either lower or higher than the European maximum levels of 1250 µg DON/kg and 100 µg ZEA/kg in 95.2% of the cases. Models 2 and 3 performed 85.7% and 100% correct predictions for DON in 2017, respectively. Model 2 predicted correctly whether the ZEA concentration was either lower or higher than the maximum level of 100 µg ZEA/kg in 100% of the cases in 2017, whereas model 3 performed 85.7% correct predictions. The models are therefore useful for the prediction of DON and ZEA concentrations in wheat grain from maize-free crop rotations based on cumulative precipitation and average temperature during wheat flowering and for differentially susceptible wheat cultivars.

Adsorption of mycotoxins by organozeolites

A long-term feeding experiment with dairy cows was performed to investigate the effects of feeding a Fusarium toxin contaminated (FUS) and a background-contaminated control (CON) ration with a mean concentrate feed proportion of 50% during the first 11 weeks after parturition (Groups FUS-50, CON-50, Period 1), and with concentrate feed proportions of 30% or 60% during the remaining 17 weeks (Groups CON-30, CON-60, FUS-30 and FUS-60, Period 2), on zearalenone (ZEN) residue levels in blood serum, milk, urine and bile. ZEN, α-zearalenol (α-ZEL) and β-zearalenol (β-ZEL), zearalanone (ZAL), α-zearalanol (α-ZAL) and β-zearalanol (β-ZAL) were determined by HPLC with fluorescence detection. The ZEN concentrations of the rations fed to Groups CON-50, FUS-50 (Period 1), CON-30, CON-60, FUS-30 and FUS-60 (Period 2) amounted to 53.1, 112.7, 35.0, 24.4, 73.8 and 72.5 µg/kg dry matter, respectively. The concentrations of ZEN, α-ZEL, β-ZEL, ZAN, α-ZAL and β-ZAL in serum, urine and milk were lower than 1, 1, 4, 100, 50 and 200 ng/g, respectively, while ZEN, α-ZEL and β-ZEL were detected in bile. Their levels changed with oral ZEN exposure in the course of the experiment and in a similar direction with concentrate feed proportion (Period 2 only). Thus the proportions of the individual β-ZEL, α-ZEL and ZEN concentrations of their sum varied only in narrow ranges of 68–76%, 6–13% and 12–20%, respectively. Interestingly, the bile concentrations of β-ZEL, α-ZEL and ZEN of Groups CON-60 and FUS-60 amounted to only approximately 50%, 45% and 62%, respectively, of those of Groups CON-30 and FUS-30 despite a similar or even lower ZEN exposure. The results indicate that conversion of ZEN to its detectable metabolites was not changed by different dietary concentrate feed proportions while their absolute levels were decreased. These findings might suggest concentrate feed proportion-dependent and rumen fermentation-mediated alterations in ZEN/metabolite degradation, and/or liver associated alterations in bile formation and turnover.

Zearalenone activates pregnane X receptor, constitutive androstane receptor and aryl hydrocarbon receptor and corresponding phase I target genes mRNA in primary cultures of human hepatocytes

Abstract. This field study aimed to investigate the relationships between the urinary zearalenone (ZEN) concentration, which reflects dietary ZEN intake, and the numbers of total and transferable embryos in superovulated cattle. A total of 38 cows (Japanese Black, n=16; Holstein, n=22) were superovulated for commercial embryo production. Urine samples were collected from all cows at the time of embryo flushing and the urinary ZEN concentration was measured. The ZEN concentration was corrected for the creatinine (Crea) concentration as follows: ZEN (pg/mL)/Crea (mg/dL); the corrected ZEN concentration was expressed in pg/mg Crea. The cows were divided into two groups according to whether the urinary ZEN level was less than (group 1) or more than (group 2) the mean value for each breed (Japanese Black: 97.4 pg/mg Crea; range 44.5–91.3 pg/mg Crea; Holstein: 155.5 pg/mg Crea; range 32.7–146.9 pg/mg Crea). The embryo flushing results were compared between the two groups within each breed. Overall, the total number of embryos collected and the number of transferable embryos did not differ significantly between the groups. These results suggest that natural ZEN contamination resulting in urine levels below the threshold value (i.e. below the maximal permissible urinary ZEN concentration) does not affect embryo production in Japanese Black and Holstein cows undergoing superovulation.