Yeast Metabolism Research Articles

Production of biolipids from volatile fatty acids of sewage sludge by Yarrowia lipolytica

Sewage sludge (SS) can be used as a fantastic source of organic compounds instead of being considered as a waste. Thus, these compounds could be converted into microbial lipids (ML) by oleaginous microorganisms, these biolipids being used as raw material for the sustainable production of biodiesel. Nevertheless, the organic compounds are trapped in the complex structures of the sludge flocs. Therefore, in this study an integrated process of sludge management was developed to produce ML as a valuable alternative to oils from agricultural sources. In this sense, wet oxidation (WO) was used as a pre-treatment process of SS in order to maximise the generation of volatile fatty acids (VFAs) mainly acetic and propionic acids. Thus, the liquid fraction was employed as a substrate to produce biolipids by Yarrowia lipolytica, without adding any kind of (micro)nutrients. The optimum conditions for the VFA generation were found to be 205 °C and 120 min, obtaining a concentration of acetic and propionic acids of 4323 ± 112 mg/L and 565 ± 25 mg/L, respectively. Besides, during the WO, ammonium nitrogen was also released, which is a vital nutrient in the metabolism of the oleaginous yeast for cell proliferation. Regarding the fermentation with Y. lipolytica, the best pH value was established at 6.5. Under these conditions, 95% of acetic acid and 100% of propionic acid were metabolised by the yeast. This implied that approximately 30% of the organic carbon present in the oxidised SS was transformed into biolipids in 48 h of cultivation. High lipid content and lipid yield coefficient (YL/S) were achieved using VFAs derived from SS, the values being 35 ± 1% and 0.23 ± 0.02 g/g, respectively. The lipid profile mainly contained monounsaturated fatty acids, such as oleic acid (46.4 ± 0.4%), making it an interesting raw material for biodiesel production. Therefore, the proposed strategy can be a promising approach to produce clean biofuels from SS.

The Role of the PAA1 Gene on Melatonin Biosynthesis in Saccharomyces cerevisiae: A Search of New Arylalkylamine N-Acetyltransferases

Recently, the presence of melatonin in fermented beverages has been correlated with yeast metabolism during alcoholic fermentation. Melatonin, originally considered a unique product of the pineal gland of vertebrates, has been also identified in a wide range of invertebrates, plants, bacteria, and fungi in the last two decades. These findings bring the challenge of studying the function of melatonin in yeasts and the mechanisms underlying its synthesis. However, the necessary information to improve the selection and production of this interesting molecule in fermented beverages is to disclose the genes involved in the metabolic pathway. So far, only one gene has been proposed as involved in melatonin production in Saccharomyces cerevisiae, PAA1, a polyamine acetyltransferase, a homolog of the vertebrate’s aralkylamine N-acetyltransferase (AANAT). In this study, we assessed the in vivo function of PAA1 by evaluating the bioconversion of the different possible substrates, such as 5-methoxytryptamine, tryptamine, and serotonin, using different protein expression platforms. Moreover, we expanded the search for new N-acetyltransferase candidates by combining a global transcriptome analysis and the use of powerful bioinformatic tools to predict similar domains to AANAT in S. cerevisiae. The AANAT activity of the candidate genes was validated by their overexpression in E. coli because, curiously, this system evidenced higher differences than the overexpression in their own host S. cerevisiae. Our results confirm that PAA1 possesses the ability to acetylate different aralkylamines, but AANAT activity does not seem to be the main acetylation activity. Moreover, we also prove that Paa1p is not the only enzyme with this AANAT activity. Our search of new genes detected HPA2 as a new arylalkylamine N-acetyltransferase in S. cerevisiae. This is the first report that clearly proves the involvement of this enzyme in AANAT activity.

Assessment of yeast physiology during industrial-scale brewing practices using the redox-sensitive dye resazurin.

Beer refermentation in bottles is an industrial process utilized by breweries where yeast and fermentable extract are added to green beer. The beer is refermented for a minimum of 2 weeks before distribution, with the physiological state of the yeast a critical factor for successful refermentation. Ideally, fresh yeast that is propagated from a dedicated propagation plant should be used for refermentation in bottles. Here, we explored the applicability of the fluorescent and redox-sensitive dye, resazurin, to assess cellular metabolism in yeast and its ability to differentiate between growth stages. We applied this assay, with other markers of yeast physiology, to evaluate yeast quality during a full-scale industrial propagation. Resazurin allowed the discrimination between the different growth phases in yeast and afforded a more in-depth understanding of yeast metabolism during propagation. This assay can be used to optimize the yeast propagation process and cropping time to improve beer quality.

BioSentinel: Validating Sensitivity of Yeast Biosensors to Deep Space Relevant Radiation.

With the imminent human exploration of deep space, it is more important than ever to understand the biological risks of deep space radiation exposure. The BioSentinel mission will be the first biological payload to study the effects of radiation beyond low Earth orbit in 50 years. This study is the last in a collection of articles about the BioSentinel biological CubeSat mission, where budding yeast cells will be used to investigate the response of a biological organism to long-term, low-dose deep space radiation. In this study, we define the methodology for detecting the biological response to space-like radiation using simulated deep space radiation and a metabolic indicator dye reduction assay. We show that there is a dose-dependent decrease in yeast cell growth and metabolism in response to space-like radiation, and this effect is significantly more pronounced in a strain of yeast that is deficient in DNA damage repair (rad51Δ) compared with a wild-type strain. Furthermore, we demonstrate the use of flight-like instrumentation after exposure to space-like ionizing radiation. Our findings will inform the development of novel and improved biosensors and technologies for future missions to deep space.

Relation of xylitol formation and lignocellulose degradation in yeast

One of the critical steps of the biotechnological production of xylitol from lignocellulosic biomass is the deconstruction of the plant cell wall. This step is crucial to the bioprocess once the solubilization of xylose from hemicellulose is allowed, which can be easily converted to xylitol by pentose-assimilating yeasts in a microaerobic environment. However, lignocellulosic toxic compounds formed/released during plant cell wall pretreatment, such as aliphatic acids, furans, and phenolic compounds, inhibit xylitol production during fermentation, reducing the fermentative performance of yeasts and impairing the bioprocess productivity. Although the toxicity of lignocellulosic inhibitors is one of the biggest bottlenecks of the biotechnological production of xylitol, most of the studies focus on how much xylitol production is inhibited but not how and where cells are affected. Understanding this mechanism is important in order to develop strategies to overcome lignocellulosic inhibitor toxicity. In this mini-review, we addressed how these inhibitors affect both yeast physiology and metabolism and consequently xylose-to-xylitol bioconversion. In addition, this work also addresses about cellular adaptation, one of the most relevant strategies to overcome lignocellulosic inhibitors toxicity, once it allows the development of robust and tolerant strains, contributing to the improvement of the microbial performance against hemicellulosic hydrolysates toxicity. KEY POINTS: • Impact of lignocellulosic inhibitors on the xylitol production by yeasts • Physiological and metabolic alterations provoked by lignocellulosic inhibitors • Cell adaptation as an efficient strategy to improve yeast's robustness.

Optimization of Campesterol-Producing Yeast Strains as a Feasible Platform for the Functional Reconstitution of Plant Membrane-Bound Enzymes.

Campesterol is a major phytosterol that plays important roles in regulating membrane properties and serves as the precursor to multiple specialized metabolites, such as the phytohormone brassinosteroids. Recently, we established a campesterol-producing yeast strain and extended the bioproduction to 22-hydroxycampesterol and 22-hydroxycampest-4-en-3-one, the precursors to brassinolide. However, there is a trade-off in growth due to the disrupted sterol metabolism. In this study, we enhanced the growth of the campesterol-producing yeast by partially restoring the activity of the sterol acyltransferase and engineering upstream FPP supply. Furthermore, genome sequencing analysis also revealed a pool of genes possibly associated with the altered sterol metabolism. Retro engineering implies an essential role of ASG1, especially the C-terminal asparagine-rich domain of ASG1, in the sterol metabolism of yeast especially under stress. The performance of the campesterol-producing yeast strain was enhanced with the titer of campesterol to 18.4 mg/L, and the stationary OD600 was improved by ∼33% compared to the unoptimized strain. In addition, we examined the activity of a plant cytochrome P450 in the engineered strain, which exhibits more than 9-fold higher activity than when expressed in the wild-type yeast strain. Therefore, the engineered campesterol-producing yeast strain also serves as a robust host for the functional expression of plant membrane proteins.

Biotransformations Performed by Yeasts on Aromatic Compounds Provided by Hop—A Review

The biodiversity of some Saccharomyces (S.) strains for fermentative activity and metabolic capacities is an important research area in brewing technology. Yeast metabolism can render simple beers very elaborate. In this review, we examine much research addressed to the study of how different yeast strains can influence aroma by chemically interacting with specific aromatic compounds (mainly terpenes) from the hop. These reactions are commonly referred to as biotransformations. Exploiting biotransformations to increase the product’s aroma and use less hop goes exactly in the direction of higher sustainability of the brewing process, as the hop generally represents the highest part of the raw materials cost, and its reduction allows to diminish its environmental impact.

Analysis of volatile compounds production kinetics: A study of the impact of nitrogen addition and temperature during alcoholic fermentation.

Among the different compounds present in the must, nitrogen is an essential nutrient for the management of fermentation kinetics, also playing a major role in the synthesis of fermentative aromas. Fermentation temperature is yet another variable that affects fermentation duration and the production of fermentative aromas in wine. The main objective of this study was thus to evaluate the combined effects of nitrogen addition-at the start of the fermentation process or during the stationary phase-at different fermentation temperatures on both fermentation kinetics and aroma synthesis kinetics. To study the impact of these three parameters simultaneously, we used an innovative transdisciplinary approach associating an online GC-MS system with an original modeling approach: a Box-Behnken experimental design combined with response surface modeling and GAM modeling. Our results indicated that all three factors studied had significant effects on fermentation and aroma production kinetics. These parameters did not impact in the same way the different families of volatile compounds. At first, obtained data showed that reduction of ester accumulation in the liquid phase at high temperature was mainly due to important losses by evaporation but also to modifications of yeast metabolic capabilities to synthetize these compounds. In a noticeable way, optimal temperature changed for liquid accumulation of the two classes of esters-23°C for acetate ester and 18°C for ethyl esters-because biological impact of temperature was different for the two chemical families. Moreover, the study of these three factors simultaneously allowed us to show that propanol is not only a marker of the presence of assimilable nitrogen in the medium but above all a marker of cellular activity. Finally, this work enabled us to gain a deeper understanding of yeast metabolism regulation. It also underlines the possibility to refine the organoleptic profile of a wine by targeting the ideal combination of fermentation temperature with initial and added nitrogen concentrations. Such observation was particularly true for isoamyl acetate for which interactions between the three factors were very strong.

Deciphering the change pattern of lipid metabolism in Saccharomyces cerevisiae responding to low temperature

In fermentation, the yield of some lipid products is deeply affected by thermal variation. However, changes in lipid metabolism responding to low temperature are still poorly understood. In this work, transcriptome and lipidomic analysis were carried out to depict the changes of lipid metabolism at low and optimal temperature. Transcriptome analysis demonstrated that ribosome biogenesis and carbon metabolism were the most enrichment pathways induced by the dropped temperature. The data revealed that yeast cells adjusted membrane fluidity by altering the contents of different lipid species (phospholipids, glycerides, sphingolipids and sterols) apart from adjusting the unsaturation level of the corresponding fatty acids. According to the transcriptome analysis of glucose-energy metabolism, Snf1 was considered as the core regulator of energy metabolism in yeast’ adapting to low temperature. These findings improve our understanding of the carbon metabolism of Saccharomyces cerevisiae under cold stress and provide valuable information for the production of high-value lipid products through metabolic engineering.

The Metabolism of Respiring Carbon Sources by Dekkera bruxellensis and Its Relation with the Production of Acetate.

Dekkera bruxellensis has been studied for several aspects of its metabolism over the past years, which has expanded our comprehension on its importance to industrial fermentation processes and uncovered its industrial relevance. Acetate is a metabolite often found in D. bruxellensis aerobic cultivations, whereas its production is linked to decreased ethanol yields. In a previous work, we aimed to understand how acetate metabolism affected the fermentation capacity of D. bruxellensis. In the present work, we evaluated the role of acetate metabolism in respiring cells using ammonium or nitrate as nitrogen sources. Our results showed that galactose is a strictly respiratory sugar and that a relevant part of its carbon is lost, while the remaining is metabolised through the Pdh bypass pathway before being assimilated into biomass. When this pathway was blocked, yeast growth was reduced while more carbon was assimilated to the biomass. In nitrate, more acetate was produced as expected, which increased carbon assimilation, although less galactose was uptaken from the medium. This scenario was not affected by the Pdh bypass inhibition. The confirmation that acetate production was crucial for carbon assimilation was brought by cultivations in pyruvate. All physiological data were connected to the expression patterns of PFK1, PDC1, ADH1, ALD3, ALD5 and ATP1 genes. Other respiring carbon sources could only be properly used by the cells when some external acetate was supplied. Therefore, the results reported herein helped in providing valuable contributions to the understanding of the oxidative metabolism in this potential industrial yeast.

The cyclic peptide G4CP2 enables the modulation of galactose metabolism in yeast by interfering with GAL4 transcriptional activity.

Genetically-encoded combinatorial peptide libraries are convenient tools to identify peptides to be used as therapeutics, antimicrobials and functional synthetic biology modules. Here, we report the identification and characterization of a cyclic peptide, G4CP2, that interferes with the GAL4 protein, a transcription factor responsible for the activation of galactose catabolism in yeast and widely exploited in molecular biology. G4CP2 was identified by screening CYCLIC, a Yeast Two-Hybrid-based combinatorial library of cyclic peptides developed in our laboratory. G4CP2 interferes with GAL4-mediated activation of galactose metabolic enzymes both when expressed intracellularly, as a recombinant peptide, and when provided exogenously, as a chemically-synthesized cyclic peptide. Our results support the application of G4CP2 in microbial biotechnology and, additionally, demonstrate that CYCLIC can be used as a tool for the rapid identification of peptides, virtually without any limitations with respect to the target protein. The possible biotechnological applications of cyclic peptides are also discussed.

Saccharomyces cerevisiae responds similarly to co-culture or to a fraction enriched in Metschnikowia pulcherrima extracellular vesicles.

The recent introduction of non-conventional yeast species as companion wine starters has prompted a growing interest in microbial interactions during wine fermentation. There is evidence of interactions through interference and exploitation competition, as well as interactions depending on physical contact. Furthermore, the results of some transcriptomic analyses suggest interspecific communication, but the molecules or biological structures involved in recognition are not well understood. In this work, we explored extracellular vesicles (EVs) as possible mediators of interspecific communication between wine yeasts. The transcriptomic response of Saccharomyces cerevisiae after 3h of contact with a fraction enriched in EVs of Metschnikowia pulcherrima was compared with that induced by active M.pulcherrima cells. Interestingly, there is a high level of overlap between the transcriptomic profiles of yeast cells challenged by either M.pulcherrima whole cells or the EV-enriched fraction. The results indicate an upregulation of yeast metabolism in response to competing species (in line with previous results). This finding points to the presence of a signal, in the EV-enriched fraction, that can be perceived by the yeast cells as a cue for the presence of competitors, even in the absence of metabolically active cells of the other species.

Evaluation of stress factors in the metabolism of Pedra-2 yeast

The objective of this study was to evaluate the composition of the fermentation substrate as well as the effect of stress factors on the metabolism of Pedra-2 yeast. An exploratory survey was conducted for the composition of fermentable carbohydrates present in sugarcane juice. For the analyses of mineral and metal content, acid digestion of organic matter was used, determined by flame atomic absorption whit a spectroscope. The pre-inoculum was prepared whit 0.10g of the freeze-dried yeasts that were inoculated and diluted in sterile saline solution. The bioreactor with 125mL Erlenmeyer flasks, in which 50mL of sterilized sugarcane broth was added and adjusted to concentrations of 18, 25 and 32°Brix, to which the yeast colonies were inoculated with the help of a platinum loop and incubated at 30 and 40°C. Samples were collected at different times to evaluate biomass production through spectrophotometry at 570nm and cell viability by counting in a Neubauer chamber with methylene blue dye. The present study points out that the associated stress factors interfere with the studied microorganism's metabolism.

The (Poly)phenolic Profile of Separate Winery By-Products Reveals Potential Antioxidant Synergies.

The by-products of grapes (Vitis vinifera L.) in the winemaking process present a diverse phytochemical profile of (poly)phenols, essentially represented by phenolic acids, flavonoids, and stilbenes, which have health benefits. In winemaking, solid (grape stems and pomace) and semisolid (wine lees) by-products are generated, negatively impacting the sustainability of the agro-food activity and the local environment. Although information on the phytochemical profile of grape stems and pomace has been reported, especially information concerning (poly)phenols, research on wine lees is necessary to take advantage of the compositional traits of this residue. So, in the present work, an updated, in-depth comparison of the (poly)phenolic profiles of these three resulting matrices in the agro-food industry has been carried out to provide new knowledge and interesting data on the action of yeast and lactic acid bacteria (LAB) metabolism in the diversification of phenolic composition; additionally, we extract complementarities for the possible joint application of the three residues. The phytochemical analysis of the extracts was carried out using HPLC-PDA-ESI-MSn. The (poly)phenolic profiles of the residues showed significant discrepancies. The results obtained showed that the greatest diversity of (poly)phenols was found in the stems of the grapes, followed closely by the lees. Through technological insights, it has been suggested that yeasts and LAB, responsible for the fermentation of must, might play a key role in the transformation of phenolic compounds. This would provide new molecules with specific bioavailability and bioactivity features, which might interact with different molecular targets and, consequently, improve the biological potential of these underexploited residues.

Different Diacetyl Perception Detected through MOX Sensors in Real-Time Analysis of Beer Samples

Beer is the most consumed alcoholic beverage; with 177.5 million kiloliters produced every year, it is one of the most relevant food products. Diacetyl is a typical byproduct of yeast metabolism that is formed during the fermentation inside breweries. The perception of this high volatile and butter-like flavor molecule varies according to the kind of beer, from a positive and highly sought characteristic to a characteristic that is avoided. Furthermore, its toxicity when inhaled has been proven. Typical diacetyl analysis includes voltametric detection and chromatographic analysis techniques. Using metal oxide sensors (MOS), this analysis can become fast and cost-effective, evaluating the differences in diacetyl concentrations through resistance variation. The S3+ (Nano Sensor Systems s.r.l.; Reggio Emilia, Italy; device can recognize volatile compounds through a tailormade array of different materials. The results can be shown on a PCA that is directly generated by the instruments and can be used to manage the productive process through an IoT integrated system. Testing different beer typology through electrochemical sensors allows for the validation of this new approach for diacetyl evaluation. The results have shown an excellent ability to detect diacetyl in different beer samples, perfectly discriminating among different concentrations.

Evaluation of Fermentative Xylitol Production Potential of Adapted Strains of Meyerozyma caribbica and Candida tropicalis from Rice Straw Hemicellulosic Hydrolysate

Dilute acid hydrolysis of lignocellulosic biomass generates inhibitors in the hydrolysate which hamper yeast metabolism and the fermentation process. Therefore, understanding the effect of these compounds on the performance of microorganisms becomes essential to achieve improved product yields. In this study, the effect of acetic acid, furfural, and hydroxymethylfurfural was evaluated on yeast growth and fermentation efficiency. Various parameters for the pretreatment of rice straw, such as an acid catalyst, and its concentration and residence time, were optimized for the maximum liberation of sugars in the hydrolysate. Further, the yeast strains Candida tropicalis and Meyerozyma caribbica were adapted for the tolerance of inhibitors at higher concentrations. A comparative analysis was carried out using un-adapted and adapted strains of Candida tropicalis and Meyerozyma caribbica for xylitol production. The findings of this study revealed that sulfuric acid (1.25% v/v) at 121 ரC for 30 min can efficiently convert rice straw xylan to xylose, with the release of 16.07 g/L xylose in the hydrolysate. Further, the adaptation results showed an increase of 76.42% and 69.33% in xylose assimilation by C. tropicalis and M. caribbica, respectively. The xylitol production with the adapted C. tropicalis was increased by 7.54% to 28.03 g/L xylitol. However, the xylitol production with the adapted M. caribbica was increased by 8.33%, yielding 26.02 g/L xylitol in the non-detoxified hydrolysate when compared to the un-adapted strains. Repeated batch fermentation was carried out for seven batches, and xylitol was found to be efficiently produced by the yeasts during five successive batches without any significant loss in the xylitol yield. Moreover, the results suggest that M. caribbica is a promising microorganism for the transformation of rice straw-derived xylose to xylitol.

Exogenous fatty acid renders the improved salt tolerance in Zygosaccharomyces rouxii by altering lipid metabolism

The yeast Zygosaccharomyces rouxii has long been used in traditional fermented food whose high quality and specific flavor are closely connected with this yeast. We previously showed that the salt tolerance of Z. rouxii could further be reinforced by the incorporation of exogenous fatty acids. While the precise mechanism is still unknown, a possible hypothesis is that exogenous fatty acids could regulate lipid metabolism, altering lipids' composition in the cell membrane. Here in this study, we try to answer this question by leveraging metabolic flux analysis and lipidomics. The results suggest that the exogenous fatty acid C12:0 with isotope 13C labeled can be absorbed by Z. rouxii cells. 134 lipids displayed abundance differentiation in lipidomics, among which most lipids were generally enhanced and the unsaturation of total lipids increased under salt stress. Combined analysis of metabolic flux and lipidome changes elucidated that Z. rouxii cells improve lipids’ metabolic flux and contents to enhance overall lipid synthesis against salt stress. Our finding thus suggests that engineering the lipid metabolism of yeast with synthetic biology could be a promising strategy for building a yeast cell factory with tolerance for green biological manufacturing in food production.

Impact of Assimilable Nitrogen Supplementation on Saccharomyces cerevisiae Metabolic Response and Aromatic Profile of Moschofilero Wine.

The concentration of nitrogen in must is critical to yeast fermentation efficiency and wine aroma profile. The present work determined the effect of the amount of yeast assimilable nitrogen (YAN) on fermentation kinetics, aroma production, and gene expression patterns of the wine yeast Saccharomyces cerevisiae. Fermentations were performed under two different YAN concentrations of must. Acetate esters, linalool, and nerol appeared to be clearly affected by the different YAN levels. Real-time-PCR results revealed that the genes involved in ethyl and acetate esters production recorded, in general, higher transcript levels under high nitrogen supplementation. In addition, an up-regulation of the BGL2 and EXG1 genes, which are related to terpenes production, was observed in the case of high nitrogen content and it is well corresponded to the terpenol concentration found. Our study revealed the impact of nitrogen supplementation on yeast metabolism and its importance to adjust wine's aromatic composition and sensory profile.

Deletion of ORM2 Causes Oleic Acid-Induced Growth Defects in Saccharomyces cerevisiae.

The endoplasmic reticulum (ER) resident proteins of the Orm family (Orm1p and Orm2p) play an essential regulatory role in sphingolipid metabolism and proteostasis of Saccharomyces cerevisiae. Sphingolipid metabolism and its relationship with yeast ORM1 and ORM2 have been studied widely, but its position in phospholipids and neutral lipids requires further studies. We found that the deletion of ORM2 reduced phospholipid levels, but orm1Δ had shown no significant alteration of phospholipids. On the contrary, neutral lipid levels and lipid droplet (LD) numbers were increased in both orm1∆ and orm2∆ cells. Unlike orm1Δ, free fatty acid (FFA) levels were steeply accumulated in orm2∆ cells, and deletion of ORM2 made the cells more sensitive towards oleic acid toxicity. Misregulation of fatty acids has been implicated in the causation of several lipid metabolic disorders. It is imminent to comprehend the control mechanisms of free fatty acid homeostasis and its pathophysiology. Our study has provided experimental evidence of ORM2 role in the lipid and fatty acid metabolism of yeast.

Metabolic profiles and fingerprints for the investigation of the influence of nitisinone on the metabolism of the yeast Saccharomyces cerevisiae

Nitisinone (2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione, NTBC) is considered a potentially effective drug for the treatment of various metabolic diseases associated with disorders of l-tyrosine metabolism however, side-effects impede its widespread use. This work aimed to broaden the knowledge of the influence of NTBC and its metabolites 2-amino-4-(trifluoromethyl)benzoic acid (ATFA), 2-nitro-4-(trifluoromethyl)benzoic acid (NTFA), and cyclohexane-1,3-dione (CHD) on the catabolism of l-tyrosine and other endogenous compounds in Saccharomyces cerevisiae. Based on a targeted analysis performed by LC–ESI–MS/MS, based on multiple reaction monitoring, it was found that the dissipation kinetics of the parent compound and its metabolites are compatible with a first-order reaction mechanism. Moreover, it has been proven that formed NTBC metabolites, such as CHD, cause a decrease in l-tyrosine, l-tryptophan, and l-phenylalanine concentrations by about 34%, 59% and 51%, respectively, compared to the untreated model organism. The overall changes in the metabolism of yeast exposed to NTBC or its derivatives were evaluated by non-targeted analysis via LC–ESI–MS/MS in the ion trap scanning mode. Based on principal components analysis, a statistically significant similarity between metabolic responses of yeast treated with ATFA or NTFA was observed. These findings facilitate further studies investigating the influence of NTBC on the human body and the mechanism of its action.