Effect of Selenium on the Growth and Lipid Accumulation of Yarrowia lipolytica Yeast

Selenium-enriched yeast, a selenium supplement, improves the rheological properties and processability of dough: From the view of yeast metabolism and gluten alteration

This study investigated the effect mechanism of selenium (Se)-enriched yeast on the rheological properties of dough from the perspective of yeast metabolism and gluten alteration. As the yeast Se content increased, the gas production rate of Se-enriched yeast slowed down, and dough viscoelasticity decreased. The maximum creep of Se-enriched dough increased by 29%, while the final creep increased by 54%, resulting in a softer dough. Non-targeted metabolomics analyses showed that Se inhibited yeast energy metabolism and promoted the synthesis of stress-resistance related components. Glutathione, glycerol, and linoleic acid contributed to the rheological property changes of the dough. The fractions and molecular weight distribution of protein demonstrated that the increase in yeast Se content resulted in the depolymerization of gluten. The intermolecular interactions, fluorescence spectrum and disulfide bond analysis showed that the disruption of intermolecular disulfide bond induced by Se-enriched yeast metabolites played an important role in the depolymerization of gluten.

Enhancing Selenium Accumulation in Rhodotorula mucilaginosa Strain 6S Using a Proteomic Approach for Aquafeed Development

It is known that selenium (Se) is an essential trace element, important for the growth and other biological functions of fish. One of its most important functions is to contribute to the preservation of certain biological components, such as DNA, proteins, and lipids, providing protection against free radicals resulting from normal metabolism. The objective of this study was to evaluate and optimize selenium accumulation in the native yeast Rhodotorula mucilaginosa 6S. Sodium selenite was evaluated at different concentrations (5-10-15-20-30-40 mg/L). Similarly, the effects of different concentrations of nitrogen sources and pH on cell growth and selenium accumulation in the yeast were analyzed. Subsequently, the best cultivation conditions were scaled up to a 2 L reactor with constant aeration, and the proteome of the yeast cultured with and without sodium selenite was evaluated. The optimal conditions for biomass generation and selenium accumulation were found with ammonium chloride and pH 5.5. Incorporating sodium selenite (30 mg/L) during the exponential phase in the bioreactor after 72 h of cultivation resulted in 10 g/L of biomass, with 0.25 mg total Se/g biomass, composed of 25% proteins, 15% lipids, and 0.850 mg total carotenoids/g biomass. The analysis of the proteomes associated with yeast cultivation with and without selenium revealed a total of 1871 proteins. The results obtained showed that the dynamic changes in the proteome, in response to selenium in the experimental medium, are directly related to catalytic activity and oxidoreductase activity in the yeast. R. mucilaginosa 6S could be an alternative for the generation of selenium-rich biomass with a composition of other nutritional compounds also of interest in aquaculture, such as proteins, lipids, and pigments.

Effects of different selenium sources and levels on the physiological state, selenoprotein expression, and production and preservation of selenium-enriched eggs in laying hens

Selenium (i.e., Se) is a trace element that is vital in poultry nutrition, and optimal forms and levels of Se are critical for poultry productivity and health. This study aimed to compare the effects of sodium selenite (SS), yeast selenium (SY), and methionine selenium (SM) at selenium levels of 0.15 mg/kg and 0.30 mg/kg on production performance, egg quality, egg selenium content, antioxidant capacity, immunity and selenoprotein expression in laying hens. The trial was conducted in a 3 × 2 factorial arrangement, and a total of 576 forty-three-wk-old Hyland Brown laying hens were randomly assigned into 6 treatment groups, with diets supplemented with 0.15 mg Se/kg and 0.3 mg Se/kg of SS, SY and SM for 8 wk, respectively. Results revealed that SM increased the laying rate compared to SS and SY (P < 0.05), whereas different selenium levels had no effect. Organic selenium improved egg quality, preservation performance, and selenium deposition compared to SS (P < 0.05), while SY and SM had different preferences for Se deposition in the yolk and albumen. Also, organic selenium enhanced the antioxidant capacity and immune functions of laying hens at 0.15 mg Se/kg, whereas no obvious improvement was observed at 0.30 mg Se/kg. Moreover, SY and SM increased the mRNA expression of most selenoproteins compared to SS (P < 0.05), with SM exhibiting a more pronounced effect. Correlation analysis revealed a strong positive association between glutathione peroxidase 2 (GPx2), thioredoxin reductases (TrxRs), selenoprotein K (SelK), selenoprotein S (SelS), and antioxidant and immune properties. In conclusion, the use of low-dose organic selenium is recommended as a more effective alternative to inorganic selenium, and a dosage of 0.15 mg Se/kg from SM is recommended based on the trail conditions.

Integrated non-targeted and targeted metabolomics analysis reveals the mechanism of inhibiting lignification and optimizing the quality of pea sprouts by combined application of nano-selenium and lentinans

BACKGROUND

Lignification causes a detrimental impact on the quality of edible sprouts. However, the mechanism of inhibition of lignification of edible sprouts by nano-selenium and lentinans remains unclear.

RESULTS

To reveal the mechanism of lignification regulation of sprouts by nano-selenium and lentinans, this study investigated the changes in antioxidant indicators, phytohormones, polyphenols, and metabolites in the lignin biosynthesis in pea sprouts following sprays of nano-selenium or/and lentinans twice. There was an overall increase in the aforementioned indices following treatment. In particular, the combined application of 5 mg L-1 nano-selenium and 20 mg L-1 lentinans was more effective than their individual applications in enhancing peroxidase, catalase, DPPH free-radical scavenging rate, luteolin, and sinapic acid, as well as inhibiting malondialdehyde generation and lignin accumulation. Combined with the results from correlation analysis, nano-selenium and lentinans may inhibit lignification by enhancing antioxidant systems, inducing phytohormone-mediated signaling, and enriching precursor metabolites (caffeyl alcohol, sinapyl alcohol, 4-coumaryl alcohol). In terms of the results of non-targeted metabolomics, the combined application of 5 mg L-1 nano-selenium and 20 mg L-1 lentinans mainly affected biosynthesis of plant secondary metabolites, biosynthesis of phenylpropanoids, phenylpropanoid biosynthesis, arginine and proline metabolism, and linoleic acid metabolism pathways, which supported and complemented results from targeted screenings.

CONCLUSION

Overall, the combined sprays of nano-selenium and lentinans showed synergistic effects in delaying lignification and optimizing the quality of pea sprouts. This study provides a novel and practicable technology for delaying lignification in the cultivation of edible sprouts. © 2023 Society of Chemical Industry.

Effects of cadmium on the synthesis of active ingredients in Salvia miltiorrhiza

Cadmium (Cd) could pose threats to human health by affecting Salvia miltiorrhiza (SM) safety. Cd enrichment trait and its effects on the active ingredient synthesis in SM remain unknown. Here we investigated the Cd concentration using ICP-MS-based method, physiologies (contents of malondialdehyde and proline, and activities of superoxide dismutase, peroxidase [POD], and catalase [CAT]), and LC-MS/MS-based metabolites of SM under 25, 50, and 100 mg kg^-1 Cd stress. The results revealed that Cd concentrations, as it rose in soil, increased in roots and leaves of SM with transfer factors and bioconcentration factors below 1 in Cd-treated groups; POD and CAT activities and proline content increased and then declined. Amino acids and organic acids (especially d-glutamine [d-Gln], l-aspartic acid [l-Asp], l-phenylalanine [l-Phe], l-tyrosine [l-Tyr], geranylgeranyl-PP [GGPP], and rosmarinic acid [RA]) contributed more in discriminating SM roots of different groups. GGPP was negatively related to l-Tyr and l-Phe, and RA was positively related to d-Gln and l-Asp in SM. These results revealed that SM belonged to a non-Cd-hyperaccumulator with most Cd accumulated in roots, Cd could enhance phenolic acid synthesis via regulating amino acid metabolism and might inhibit tanshinone synthesis by declining the GGPP content, and proline, POD, and CAT played vital roles in resisting Cd stress. These provided new ideas and theoretical basis for further study on medical plants' response to heavy metals.

Novel evolved Yarrowia lipolytica strains for enhanced growth and lipid content under high concentrations of crude glycerol

BACKGROUND

Yarrowia lipolytica is a well-studied oleaginous yeast known for its ability to accumulate and store intracellular lipids, while growing on diverse, non-conventional substrates. Amongst them, crude glycerol, a low-cost by-product of the biodiesel industry, appears to be an interesting option for scaling up a sustainable single-cell oil production process. Adaptive laboratory evolution (ALE) is a powerful tool to force metabolic adaptations endowing tolerance to stressful environmental conditions, generating superior phenotypes with industrial relevance.

RESULTS

Y. lipolytica MUCL 28849 underwent ALE in a synthetic medium with increasing concentration of pure or crude glycerol as a stressing factor (9-20% v/v) for 520 generations. In one case of pure glycerol, chemical mutagenesis with ethyl methanesulfonate (EMS) was applied prior to ALE. Growth profile, biomass production and lipid content of 660 evolved strains (EVS), revealed 5 superior isolates; exhibiting from 1.9 to 3.6-fold increase of dry biomass and from 1.1 to 1.6-fold increase of lipid concentration compared to the parental strain, when grown in 15% v/v crude glycerol. NGS for differential gene expression analysis, showed induced expression in all EVS affecting nucleosomal structure and regulation of transcription. As strains differentiated, further changes accumulated in membrane transport and protein transport processes. Genes involved in glycerol catabolism and triacylglycerol biosynthesis were overexpressed in two EVS. Mismatches and gaps in the expressed sequences identified altered splicing and mutations in the EVS, with most of them, affecting different components of septin ring formation in the budding process. The selected YLE155 EVS, used for scale-up cultivation in a 3L benchtop bioreactor with 20% v/v crude glycerol, achieved extended exponential phase, twofold increase of dry biomass and lipid yields at 48 h, while citric acid secretion and glycerol consumption rates were 40% and 50% lower, respectively, compared to the parental strain, after 24 h of cultivation.

CONCLUSION

ALE and EMS-ALE under increasing concentrations of pure or crude glycerol generated novel Y. lipolytica strains with enhanced biomass and lipid content. Differential gene expression analysis and scale-up of YLE155, illustrated the potential of the evolved strains to serve as suitable "chassis" for rational engineering approaches towards both increased lipid accumulation, and production of high-added value compounds, through efficient utilization of crude glycerol.

Seleno Containing Compounds as Potent and Selective Antifungal Agents

Fungal promoted infections are becoming a severe health global emergency due to drug-resistant phenomena and zoonosis. This work investigated compounds bearing acyl-/selenoureido moieties and primary/secondary sulfonamide groups as novel antifungal agents acting through organism-directed selenium toxicity and inhibition of the newly emergent therapeutic target, the Carbonic Anhydrases (CAs; EC 4.2.1.1). Reported data clearly indicate that seleno-containing scaffolds with respect to the standard-of-care drugs showed appreciable antifungal activity, which was suppressed when the chalcogen was replaced with its cognate isosteric elements sulfur and oxygen. In addition, such compounds showed excellent selectivity against Malassezia pachydermatis over its related genus strains Malassezia furfur and Malassezia globosa. Safe cytotoxicity profiles on bovine kidney cells (MDBK) and human HaCat cells, as well as the shallow hemolytic activity on defibrinated sheep blood, allowed us to consider these compounds as up-and-coming novel antifungals.

Brown seaweed hydrolysate as a promising growth substrate for biomass and lipid synthesis of the yeast yarrowia lipolytica

Biomass of the brown algae Fucus vesiculosus and Saccharina latissima is a promising, renewable feedstock because of the high growth rate, accessibility and content of glucose and mannitol. Saccharification of seaweeds is a simple process due to the lack of lignocellulose in the cell wall. The high content of glucose and mannitol makes these seaweeds an attractive feedstock for lipid production in the yeast Yarrowia lipolytica. This study demonstrated that hydrolysates of brown algae biomass can be applied as a substrate for synthesis of yeast biomass and lipids without any supplementation. To increase the lipid titer in yeast biomass, we employed an engineered strain of Y. lipolytica overexpressing DGA1/DGA2. In consequence, the C/N ratio has a lower impact on lipid synthesis. Moreover, the applied substrates allowed for high synthesis of unsaturated fatty acids (UFA); the level exceeded 90% in the fatty acid pool. Oleic (C18:1) and linoleic acids (C18:2) achieved the highest content. The study showed that Y. lipolytica is able to grow on the seaweed hydrolysate and produces a high content of UFA in the biomass.

Structure of fungal communities in sequencing batch reactors operated at different salinities for the selection of triacylglyceride-producers from a fish-canning lipid-rich waste stream

Oleaginous fungi natively accumulate large amounts of triacylglycerides (TAG), widely used as precursors for sustainable biodiesel production. However, little attention has been paid to the diversity and roles of fungal mixed microbial cultures (MMCs) in sequencing batch reactors (SBR). In this study, a lipid-rich stream produced in the fish-canning industry was used as a substrate in two laboratory-scale SBRs operated under the feast/famine (F/F) regime to enrich microorganisms with high TAG-storage ability, under two different concentrations of NaCl (SBR-N: 0.5g/L; SBR-S: 10g/L). The size of the fungal community in the enriched activated sludge (EAS) was analyzed using 18S rRNA-based qPCR, and the fungal community structure was determined by Illumina sequencing. The different selective pressures (feeding strategy and control of pH) implemented in the enrichment SBRs throughout operation increased the abundance of total fungi. In general, there was an enrichment of genera previously identified as TAG-accumulating fungi (Apiotrichum, Candida, Cutaneotrichosporon, Geotrichum, Haglerozyma, Metarhizium, Mortierella, Saccharomycopsis, and Yarrowia) in both SBRs. However, the observed increase of their relative abundances throughout operation was not significantly linked to a higher TAG accumulation.

Validated Growth Rate-Dependent Regulation of Lipid Metabolism in Yarrowia lipolytica

Given the strong potential of Yarrowia lipolytica to produce lipids for use as renewable fuels and oleochemicals, it is important to gain in-depth understanding of the molecular mechanism underlying its lipid accumulation. As cellular growth rate affects biomass lipid content, we performed a comparative proteomic analysis of Y. lipolytica grown in nitrogen-limited chemostat cultures at different dilution rates. After confirming the correlation between growth rate and lipid accumulation, we were able to identify various cellular functions and biological mechanisms involved in oleaginousness. Inspection of significantly up- and downregulated proteins revealed nonintuitive processes associated with lipid accumulation in this yeast. This included proteins related to endoplasmic reticulum (ER) stress, ER–plasma membrane tether proteins, and arginase. Genetic engineering of selected targets validated that some genes indeed affected lipid accumulation. They were able to increase lipid content and were complementary to other genetic engineering strategies to optimize lipid yield.

A novel yeast strain Geotrichum sp. CS-67 capable of accumulating heavy metal ions

Bioremediation, which has several advantages over traditional methods, represents an alternative means of dealing with heavy metal pollution. We screened for microorganisms showing heavy metal tolerance in polluted mangrove soils. A novel yeast, Geotrichum sp. CS-67, was discovered and tested for tolerance of Cu²⁺, Zn²⁺, and Ni²⁺. Zn²⁺ was the most efficiently sequestered by Geotrichum sp. CS-67 followed by Ni²⁺ and Cu²⁺. Zn²⁺ and Ni²⁺ were actively taken up into the cell, while Cu²⁺ was adsorbed to the cell wall. We used RNA-Seq to show that a large number of genes involved in the physiological and biochemical processing of heavy metals were differentially expressed in this yeast when it was subjected to Zn²⁺ and Ni²⁺ stress. From this panel, we selected the SED1, GDI1 and ZRT1 genes for validation by qRT-PCR and discovered that, during Zn²⁺ and Ni²⁺ stress, SED1 and GDI1 were upregulated, while ZRT1 was downregulated, which was consistent with the RNA-Seq results and the biochemical function of these genes. In conclusion, the novel yeast Geotrichum sp. CS-67 has a marked ability to accumulate heavy metal ions, making it of great interest as a possible microbial agent for heavy metal pollution remediation in the future.

A comprehensive assessment of Yarrowia lipolytica and its interactions with metals: Current updates and future prospective

The non-conventional yeast Yarrowia lipolytica has been popular as a model system for understanding biological processes such as dimorphism and lipid accumulation. The organism can efficiently utilize hydrophobic substrates (hydrocarbons and triglycerides) thereby rendering it relevant in bioremediation of oil polluted environments. The current review focuses on the interactions of this fungus with metal pollutants and its potential application in bioremediation of metal contaminated locales. This fungus is intrinsically equipped with a variety of physiological and biochemical features that enable it to tide over stress conditions induced by the presence of metals. Production of enzymes such as phosphatases, reductases and superoxide dismutases are worth a special mention. In the presence of metals, levels of inherently produced metal binding proteins (metallothioneins) and the pigment melanin are seen to be elevated. Morphological alterations with respect to biofilm formation and dimorphic transition from yeast to mycelial form are also induced by certain metals. The biomass of Y. lipolytica is inherently important as a biosorbent and cell surface modification, process optimization or whole cell immobilization techniques have aided in improving this capability. In the presence of metals such as mercury, cadmium, copper and uranium, the culture forms nanoparticulate deposits. In addition, on account of its intrinsic reductive ability, Y. lipolytica is being exploited for synthesizing nanoparticles of gold, silver, cadmium and selenium with applications as antimicrobial compounds, location agents for bioimaging and as feed supplements. This versatile organism thus has great potential in interacting with various metals and addressing problems related to their pollutant status.

Shifting the distribution: modulation of the lipid profile in Yarrowia lipolytica via iron content

Microbial fermentation offers a sustainable source of fuels, commodity chemicals, and pharmaceuticals, yet strain performance is influenced greatly by the growth media selected. Specifically, trace metals (e.g., iron, copper, manganese, zinc, and others) are critical for proper growth and enzymatic function within microorganisms yet are non-standardized across media formulation. In this work, the effect of trace metal supplementation on the lipid production profile of Yarrowia lipolytica was explored using tube scale fermentation followed by biomass and lipid characterization. Addition of iron (II) to the chemically defined Yeast Synthetic Complete (YSC) medium increased final optical density nearly twofold and lipid production threefold, while addition of copper (II) had no impact. Additionally, dose-responsive changes in lipid distribution were observed, with the percent of oleic acid increasing and stearic acid decreasing as initial iron concentration increased. These changes were reversible with subsequent iron-selective chelation. Use of rich Yeast Peptone Dextrose (YPD) medium enabled further increases in the production of two specialty oleochemicals ultimately reaching 63 and 47% of the lipid pool as α-linolenic acid and cyclopropane fatty acid, respectively, compared to YSC medium. Selective removal of iron (II) natively present in YPD medium decreased this oleochemical production, ultimately aligning the lipid profile with that of non-supplemented YSC medium. These results provide further insight into the proposed mechanisms for iron regulation in yeasts especially as these productions strains contain a mutant allele of the iron regulator, mga2. The work presented here also suggests a non-genetic method for control of the lipid profile in Y. lipolytica for use in diverse applications. KEY POINTS: • Iron supplementation increases cell density and lipid titer in Yarrowia lipolytica. • Iron addition reversibly alters lipid portfolio increasing linolenic acid. • Removal of iron from YPD media provides a link to enhanced oleochemical production.

Transcriptomic analysis of formic acid stress response in Saccharomyces cerevisiae

Formic acid is a representative small molecule acid in lignocellulosic hydrolysate that can inhibit the growth of Saccharomyces cerevisiae cells during alcohol fermentation. However, the mechanism of formic acid cytotoxicity remains largely unknown. In this study, RNA-Seq technology was used to study the response of S. cerevisiae to formic acid stress at the transcriptional level. Scanning electron microscopy and Fourier transform infrared spectroscopy were conducted to observe the surface morphology of yeast cells. A total of 1504 genes were identified as being differentially expressed, with 797 upregulated and 707 downregulated genes. Transcriptomic analysis showed that most genes related to glycolysis, glycogen synthesis, protein degradation, the cell cycle, the MAPK signaling pathway, and redox regulation were significantly induced under formic acid stress and were involved in protein translation and synthesis amino acid synthesis genes were significantly suppressed. Formic acid stress can induce oxidative stress, inhibit protein biosynthesis, cause cells to undergo autophagy, and activate the intracellular metabolic pathways of energy production. The increase of glycogen and the decrease of energy consumption metabolism may be important in the adaptation of S. cerevisiae to formic acid. In addition, formic acid can also induce sexual reproduction and spore formation. This study through transcriptome analysis has preliminarily reveal the molecular response mechanism of S. cerevisiae to formic acid stress and has provided a basis for further research on methods used to improve the tolerance to cell inhibitors in lignocellulose hydrolysate.

Effects of Nitrogen and Phosphorus Limitation on Fatty Acid Contents in Aspergillus oryzae

Aspergillus oryzae, commonly known as koji mold, has been widely used for the large-scale production of food products (sake, makgeolli, and soy sauce) and can accumulate a high level of lipids. In the present study, we showed the dynamic changes in A. oryzae mycelium growth and conidia formation under nitrogen and phosphorus nutrient stress. The fatty acid profile of A. oryzae was determined and the content of unsaturated fatty acid was found increased under nitrogen and phosphorus limitation. Oleic acid (C18:1), linoleic acid (C18:2), and γ-linolenic acid (C18:3) production were increased on five nitrogen and phosphorus limitation media, especially on nitrogen deep limitation and phosphorus limitation group, showing a 1. 2-, 1. 6-, and 2.4-fold increment, respectively, compared with the control. Transcriptomic analysis showed the expression profile of genes related to nitrogen metabolism, citrate cycle, and linoleic acid synthesis, resulting in the accumulation of unsaturated fatty acid. qRT-PCR results further confirmed the reliability and availability of the differentially expressed genes obtained from the transcriptome analysis. Our study provides a global transcriptome characterization of the nitrogen and phosphorus nutrient stress adaptation process in A. oryzae. It also revealed that the molecular mechanisms of A. oryzae respond to nitrogen and phosphorus stress. Our finding facilitates the construction of industrial strains with a nutrient-limited tolerance.

Recent development in Se-enriched yeast, lactic acid bacteria and bifidobacteria

Endemic selenium (Se) deficiency is a major worldwide nutritional challenge. Organic Se can be synthesized through physical and chemical methods that are conducive to human absorption, but its high production cost and low output cannot meet the actual demand for Se supplementation. Some microbes are known to convert inorganic Se into organic forms of high nutritional value and Se-enriched probiotics are the main representatives. The aim of the present review is to describe the characteristics of Se-enriched yeast, lactic acid bacteria, bifidobacteria and discuss their Se enrichment mechanisms. Se products metabolized by Se-enriched probiotics have been classified, such as Se nanoparticles (SeNPs) and selenoprotein, and their bioactivities have been assessed. The factors affecting the Se enrichment capacity of probiotics and their application in animal feed, food additives, and functional food production have been summarized. Moreover, a brief summary and the development of Se-enriched probiotics, particularly their potential applications in the field of biomedicine have been provided. In conclusion, Se-enriched probiotics not just have a wide range of applications in the food industry but also have great potential for application in the field of biomedicine in the future.

The aspects of microbial biomass use in the utilization of selected waste from the agro-food industry

Cellular biomass of microorganisms can be effectively used in the treatment of waste from various branches of the agro-food industry. Urbanization processes and economic development, which have been intensifying in recent decades, lead to the degradation of the natural environment. In the first half of the 20th century, problems related to waste management were not as serious and challenging as they are today. The present situation forces the use of modern technologies and the creation of innovative solutions for environmental protection. Waste of industrial origin are difficult to recycle and require a high financial outlay, while the organic waste of animal and plant origins, such as potato wastewater, whey, lignin, and cellulose, is dominant. In this article, we describe the possibilities of using microorganisms for the utilization of various waste products. A solution to reduce the costs of waste disposal is the use of yeast biomass. Management of waste products using yeast biomass has made it possible to generate new metabolites, such as β-glucans, vitamins, carotenoids, and enzymes, which have a wide range of industrial applications. Exploration and discovery of new areas of applications of yeast, fungal, and bacteria cells can lead to an increase in their effective use in many fields of biotechnology.

High Efficacy of Ozonated Oils on the Removal of Biofilms Produced by Methicillin-Resistant Staphylococcus aureus (MRSA) from Infected Diabetic Foot Ulcers

Ozone has a high wound healing capacity and antibacterial properties and can be used as a complementary treatment in infections. Methicillin-resistant S. aureus (MRSA) is the most common pathogen found in infected diabetic foot ulcers. Most of MRSA are resistant to several classes of antibiotics and, therefore, there is a need for new, effective, and well-tolerated agents. Thus, we aimed evaluate the antimicrobial and antibiofilm potentials of ozonated vegetable oils against MRSA strains isolated from diabetic foot ulcers. Six ozonated oils were produced with concentrations of ozone ranging from 0.53 to 17 mg of ozone/g of oil. The peroxide values were determined for each oil. Ozonated oils content on fatty acid was determined by gas chromatography equipped with a flame ionization detector. The antimicrobial susceptibility testing was performed by the Kirby–Bauer disk diffusion method and the effect of ozonated oils on biofilm formation ability and on established biofilms was investigated. In general, the content in identified unsaturated fatty acid in oils decreased with the increase of ozonation time and, consequently, the peroxide value increased. Most bacterial strains were inhibited by ozonated oil at a concentration of 4.24 mg/g. Ozonated oils had moderate to high ability to remove adhered cells and showed a high capacity to eradicate 24 h old biofilms. Our results show promising use of ozonated oils on the treatment of infections, in particular those caused by multidrug-resistant MRSA strains.