Patulin Biodegradation Mechanism Study in Pichia guilliermondii S15-8 Based on PgSDR-A5D9S1

Patulin contamination has become a bottleneck problem in the safe production of fruit products, although biodegradation technology shows potential application value in patulin control. In the present study, the patulin biodegradation mechanism in a probiotic yeast, Pichia guilliermondii S15-8, was investigated. Firstly, the short-chain dehydrogenase PgSDR encoded by gene A5D9S1 was identified as a patulin degradation enzyme, through RNA sequencing and verification by qRT-PCR. Subsequently, the exogenous expression system of the degradation protein PgSDR-A5D9S1 in E. coli was successfully constructed and demonstrated a more significant patulin tolerance and degradation ability. Furthermore, the structure of PgSDR-A5D9S1 and its active binding sites with patulin were predicted via molecular docking analysis. In addition, the heat-excited protein HSF1 was predicted as the transcription factor regulating the patulin degradation protein PgSDR-A5D9S1, which may provide clues for the further analysis of the molecular regulation mechanism of patulin degradation. This study provides a theoretical basis and technical support for the industrial application of biodegradable functional strains.

Effects of Pretreatments on Patulin Removal from Apple Juices Using Lactobacilli: Binding Stability in Simulated Gastrointestinal Condition and Modeling

Recently, researchers have reported the presence of patulin as a mycotoxin in commercial apple products, especially apple juices. The aim of this study was to assess adsorption of patulin from artificially contaminated apple juice using two lactic acid bacteria (LAB) strains of Lactobacillus acidophilus ATCC 4356 and Lactobacillus plantarum ATCC 8014. Furthermore, effects of five physical and chemical pretreatments on the patulin adsorption were investigated. Results demonstrated that patulin adsorption abilities of both strains increased with NaOH pretreatment but decreased after autoclaving. The NaOH-treated L. plantarum ATCC 8014 showed the best removal rate (59.74%) after 48 h of refrigerated storage, compared with the NaOH-treated L. acidophilus ATCC 4356 (52.36%). Moreover, stability of the LAB-patulin complex was assessed in simulated gastrointestinal tract conditions and a low quantity of patulin was released into the solution. The patulin adsorption process by NaOH-treated L. plantarum ATCC 8014 followed Freundlich isotherm model and pseudo-second-order kinetic model. Fourier transform infrared spectroscopy showed that polysaccharide and protein components of the L. plantarum ATCC 8014 cell wall played key roles in patulin adsorption. The major functional groups of the cell wall that were involved in adsorbing patulin included -OH/-NH, -CH₂, C=O, and C-O groups. The current results suggest that NaOH-treated L. plantarum ATCC 8014 cells include the potential to detoxify patulin-contaminated apple juices.

Viability of the use of mycotoxin adsorbent in the finishing of Texel lambs in confinement

The objective of the present study was to evaluate the viability of a mycotoxin adsorbent based on beta-glucans from cell walls of Saccharomyces cerevisiae and bentonites in the diets of confined lambs of the Texel breed. Twenty-four lambs (12 males and 12 females) with an average weight of 18.6 kg ± 1.6 were divided into two groups: treated (with adsorbent) and control. The animal diets contained the mycotoxins aflatoxin B1, fumonisin B1 and B2, zearalenone, and deoxynivalenol in concentrations within guidance levels. The animals were slaughtered with body weight of approximately 26.4 kg. The performance and carcass variables of the lambs were evaluated. The daily weight gain was higher in the treated group (216.24 g) than in the control group (185.90 g). The averages for loin eye area, subcutaneous fat thickness, and marbling were 13.93 cm², 2.66 mm, and 3.20 in the treated group and 12.16 cm², 2.6 mm, and 3.25 in the control group, respectively. The true, hot, and cold carcass yield, and the carcass cooling losses did not differ between groups. The carcasses were similar in conformation and fat finishing degree, with averages of 3.95 and 3.83, respectively. To the best of our knowledge, this is the first study to evaluate the effect of a mycotoxin additive in the diet of finishing lambs. The use of mycotoxin adsorbent in confined lambs was feasible, and its use resulted in greater daily weight gain in lambs and average net profit.

Mycotoxins in Feed and Food and the Role of Ozone in Their Detoxification and Degradation: An Update

Mycotoxins are secondary metabolites produced by some filamentous fungi, which can cause toxicity in animal species, including humans. Because of their high toxicological impacts, mycotoxins have received significant consideration, leading to the definition of strict legislative thresholds and limits in many areas of the world. Mycotoxins can reduce farm profits not only through reduced crop quality and product refusal, but also through a reduction in animal productivity and health. This paper briefly addresses the impacts of mycotoxin contamination of feed and food on animal and human health, and describes the main pre- and post-harvest systems to control their levels, including genetic, agronomic, biological, chemical, and physical methods. It so highlights (i) the lack of effective and straightforward solutions to control mycotoxin contamination in the field, at pre-harvest, as well as later post-harvest; and (ii) the increasing demand for novel methods to control mycotoxin infections, intoxications, and diseases, without leaving toxic chemical residues in the food and feed chain. Thus, the broad objective of the present study was to review the literature on the use of ozone for mycotoxin decontamination, proposing this gaseous air pollutant as a powerful tool to detoxify mycotoxins from feed and food.

Non-Saccharomyces Yeasts and Organic Wines Fermentation: Implications on Human Health

A relevant trend in winemaking is to reduce the use of chemical compounds in both the vineyard and winery. In organic productions, synthetic chemical fertilizers, pesticides, and genetically modified organisms must be avoided, aiming to achieve the production of a “safer wine”. Safety represents a big threat all over the world, being one of the most important goals to be achieved in both Western society and developing countries. An occurrence in wine safety results in the recovery of a broad variety of harmful compounds for human health such as amines, carbamate, and mycotoxins. The perceived increase in sensory complexity and superiority of successful uninoculated wine fermentations, as well as a thrust from consumers looking for a more “natural” or “organic” wine, produced with fewer additives, and perceived health attributes has led to more investigations into the use of non-Saccharomyces yeasts in winemaking, namely in organic wines. However, the use of copper and sulfur-based molecules as an alternative to chemical pesticides, in organic vineyards, seems to affect the composition of grape microbiota; high copper residues can be present in grape must and wine. This review aims to provide an overview of organic wine safety, when using indigenous and/or non-Saccharomyces yeasts to perform fermentation, with a special focus on some metabolites of microbial origin, namely, ochratoxin A (OTA) and other mycotoxins, biogenic amines (BAs), and ethyl carbamate (EC). These health hazards present an increased awareness of the effects on health and well-being by wine consumers, who also enjoy wines where terroir is perceived and is a characteristic of a given geographical area. In this regard, vineyard yeast biota, namely non-Saccharomyces wine-yeasts, can strongly contribute to the uniqueness of the wines derived from each specific region.

Exogenous Calcium Ions Enhance Patulin Adsorption Capability of Saccharomyces cerevisiae

Patulin contamination is a serious issue that restricts the development of the global fruit processing industry. Yeasts adsorb patulin more effectively than other microbial adsorbents, and this adsorption process depends mainly on the function of the cell wall. The present study examined the effect of exogenous calcium, in concentrations ranging from 0 to 1 mol/L, on Saccharomyces cerevisiae cell wall structure and on patulin adsorption capability; the patulin adsorption capability of yeast was found to strengthen with an increase in exogenous calcium concentrations from 1 × 10^-4 to 1 × 10^-2 mol/L. Moreover, yeast cell wall thickness, β-1,3-glucan content, and the activities of the key catalytic enzymes β-1,3-glucanase and β-1,3-glycosyl transferase were all increased within this range. The results indicate that exogenous calcium activates key enzymes that are crucial for cell wall network formation and patulin adsorption capability.

Mycotoxin patulin in food matrices: occurrence and its biological degradation strategies

Patulin is a mycotoxin produced by a number of filamentous fungal species. It is a polyketide secondary metabolite which can gravely cause human health problems and food safety issues. This review deals with the occurrence of patulin in major food commodities from 2008 to date, including historical aspects, source, occurrence, regulatory limits and its toxicity. Most importantly, an overview of the recent research progress about the biodegradation strategies for contaminated food matrices is provided. The physical and chemical approaches have some drawbacks such as safety issues, possible losses in the nutritional quality, chemical hazards, limited efficacy, and high cost. The biological decontamination based on elimination or degradation of patulin using yeast, bacteria, and fungi has shown good results and it seems to be attractive since it works under mild and environment-friendly conditions. Further studies are needed to make clear the detoxification pathways by available potential biosorbents and to determine the practical applications of these methods at a commercial level to remove patulin from food products with special reference to their effects on sensory characteristics of foods.

Patulin removal from apple juice using a novel cysteine-functionalized metal-organic framework adsorbent

Patulin (PAT) is one of the most common toxic contaminants of apple juice, which causes severe food safety issues throughout the apple industry. In order to remove PAT efficiently, a metal-organic framework-based adsorbent (UiO-66(NH₂)@Au-Cys) was successfully synthesized and used for PAT removal from juice-pH simulation solution and real apple juice. Batch adsorption experiments were systematically performed to study the adsorption behavior for PAT. The results showed that adsorption process could be well described by the Pseudo-second order model and Freundlich isotherm model. The maximum adsorption capacity (4.38 µg/mg) was 10 times higher than the microbe-based biosorbents. Thermodynamic investigation demonstrated that adsorption process was spontaneous and endothermic. Furthermore, no marked cytotoxicity on NIH 3T3 cell lines was observed when the concentration of the adsorbent was lower than 10 μg/mL. Therefore, UiO-66(NH₂)@Au-Cys is a potential adsorbent for PAT removal from apple juice with little quality changes.