Search Results (184)

Sustainability represents a significant global challenge, requiring a balance between environmental impact and the use of natural resources. White biotechnology, which uses microorganisms and enzymes for environmentally friendly products and processes, offers promising solutions to support a growing population. Within this context, the yeast Yarrowia lipolytica stands out, so we investigated the generation of biomass from two wild strains (ATCC 9773 and NRRL Y-50997) using different carbon sources. Additionally, protein content and amino acid profiles were assessed via standardized analytical methods to evaluate their potential as nutritional yeasts. Both strains demonstrated potential as nutritional yeasts, with biomass productivities of up to 35.5 g/L and 42 g/L, respectively. The protein content was high, with 58.8% for ATCC 9773 and 58.2% for NRRL Y-50997. Furthermore, the strains presented essential amino acid contents of 62.6% and 41.5%, with lysine being the most abundant amino acid. These findings underscore the versatility and productivity of Y. lipolytica, highlighting its potential for sustainable biotechnological applications such as single-cell protein production. Full article

This study investigated the potential of Yarrowia lipolytica, an oleaginous yeast, for producing lipid-rich biomass and its application in food technology. According to EFSA guidelines, lipid-rich biomass is recognized as a novel food with potential nutritional and technological value. However, cost-effective and scalable production of such biomass remains a challenge. The yeast was cultured in a nitrogen-limited medium using a cost-containment strategy based on the use of waste carbon sources, such as post-frying oil and untreated tap water. The composed batch culture approach studied in the experiments presented an example that reduces the cost of yeast biomass biosynthesis. This research aimed to characterize the biomass to assess its nutritional quality and suitability for food applications. Cultures were conducted in a laboratory bioreactor with a working volume of 4 litres. Key kinetic parameters were determined, including biomass yield (X), maximum lipid concentration (Lmax), lipid yield, protein yield relative to substrate and the specific rate of lipid synthesis or protein content and other cellular components. The biomass of Y. lipolytica demonstrated a high lipid content (39.43–50.53%), with significant levels of protein (24.16–27.03%) and unsaturated fatty acids, including oleic acid (62.73–66.44%) and linoleic acid (19.40–21.40%). Lipid-rich biomass produced in cultures with shorter times (20 h), which ended in the logarithmic growth phase, exhibited lower oxidative stability than longer cultures (65 h), which ended in the stationary growth phase. The results of this study highlighted that waste carbon sources and untreated tap water did not significantly impact the biomass yield or the nutritional profile, but did affect the stability of the produced oil. The biomass of Y. lipolytica, containing over 20% lipids, could serve as a promising raw material for food technology, providing a sustainable alternative to traditional vegetable oils. This work makes an important contribution to the development of alternative lipid sources by integrating waste processing in bioreactor-scale culture and kinetic modelling. Full article

Olive oil production generates vast quantities of by-products, with olive mill wastewater (OMW) being a particularly challenging effluent. Characterized by its dark color, high acidity, and rich composition of organic matter, phenolic compounds, and residual oils, OMW resists conventional degradation methods and poses significant environmental risks due to its phytotoxicity and microbial inhibition. Addressing this issue requires sustainable solutions that align with circular economy principles. A promising strategy involves the biotechnological valorization of OMW using the non-conventional yeast Yarrowia lipolytica, which thrives on organic-rich substrates and converts them into high-value metabolites. This review provides a comprehensive analysis of recent advances in Y. lipolytica applications for OMW valorization, emphasizing its role in developing eco-friendly industrial processes. It begins by outlining the physicochemical challenges of OMW and the metabolic versatility of Y. lipolytica, including its ability to adapt to acidic, phenolic-rich environments. Subsequent sections critically evaluate the yeast’s capacity to synthesize commercially valuable products such as lipases (used in the food and biofuel industries), citric acid (a food and pharmaceutical additive), and polyols like mannitol and erythritol (low-calorie sweeteners). Strategies to optimize microbial productivity, such as substrate pre-treatment, nutrient supplementation, and process engineering, are also discussed. By synthesizing current research, the review highlights how Y. lipolytica-driven OMW valorization can mitigate environmental harm while creating economic opportunities, bridging the gap between waste management and green chemistry. Full article

European hedgehogs are an important reservoir for many pathogens of health interest. Since hedgehogs live in close contact with humans, potential zoonotic fungi raise significant public health concerns, especially in areas with a high hedgehog density. From 2020 to 2023, 134 hedgehogs were surveyed for potential zoonotic fungi. Non-invasive methods were used, such as brushing live animals with a sterile toothbrush and taking oral and rectal swabs from deceased ones (86 animals). Dermatophytes were cultured on Dermasel agar and identified using molecular tools, while yeasts were isolated on Sabouraud agar with chloramphenicol and determined using Candida Chromogenic agar (MicroBiolDiagnostici^®, Cagliari, Italy) and MALDI-TOF (Microflex LT Smart Biotyper with FlexControlBiotyper 3.4 software, Bruker Daltonics, Bremen, Germany). Minimum inhibitory concentrations (MICs) were determined for Candida albicans isolates. Dermatophytes were found in just one hedgehog (0.8%, 95% C.I.: 0–0.04), identified as Paraphyton mirabile. Yeasts were detected in 22 of 86 hedgehogs (25.6%, 95% C.I.: 16.4–34.8), with 25 isolates obtained, including 21 Candida albicans, 2 Yarrowia lipolytica, 1 Rhodotorula mucilaginosa, and 1 Meyerozyma guilliermondii. All C. albicans isolates showed a high susceptibility to the antimycotic panel tested. Monitoring zoonotic fungi harbored by European hedgehogs, as well as raising public awareness on the topic, is of great importance for public health. Full article

Lipase production by the strictly aerobic yeast Yarrowia lipolytica is closely related to the content of dissolved oxygen in the culture medium. Some strategies to improve oxygen transfer to microorganisms have already been used, such as the use of perfluorocarbons (PFCs). The present work investigates the influence of agitation speed and the use of perfluorodecalin (PFC) on the profile of the produced lipases. Lipase production increased 2.5-fold with a higher agitation speed (550 to 650 rpm) without PFCs in the medium. The presence of an oxygen carrier led to a significant 91% increase in lipase production at lower shaking speeds compared to the assay without PFC; however, an increase in lipase production was not detected with PFC at 650 rpm. The protein profiles exhibited typical bands for two lipases produced (near 40 and 60 kDa), and these bands became more intense when PFC was added during production, as a result of the large enhancement in lipolytic activity. Additionally, the protein profiles obtained from extracts at 650 rpm were clearer and more selective regardless of the presence of PFC, suggesting an enhancement in specific activity associated with increased shaking. These findings highlight the significant impact of oxygen availability on lipase production, offering valuable insights for industrial applications. Full article

This study investigates the waste-free bioconversion of glucose to erythritol using the UV-mutagenized strain Yarrowia lipolytica Wratislavia KI UV15. This research focuses on optimizing fermentation parameters to enhance erythritol yield, with a key emphasis on utilizing post-crystallization erythritol filtrate as a primary carbon source, promoting a cost-effective and sustainable approach to erythritol production. The experimental design included systematic variations in ammonium sulfate concentration, yeast extract supplementation, and initial glucose concentration. The results demonstrate that the UV15 strain achieves high erythritol production efficiency. An optimal nitrogen source concentration (3.1 g/L) and reduced yeast extract levels (0.25 g/L) provided the best results, achieving a maximum erythritol concentration of 174.8 g/L with a yield of 58.2%. Furthermore, lowering the initial glucose concentration further improved process efficiency, confirming the feasibility of using post-crystallization filtrate as an effective and sustainable carbon source. These findings highlight the biotechnological potential of Y. lipolytica UV15 in erythritol production, demonstrating its adaptability to waste-derived substrates and advancing the development of economically viable, environmentally sustainable production methods. Full article

Phytases of the PhyD class according to their pH optimum (7.0–7.8) and high thermal stability can claim to be used in the production of feed supplements. However, today they have no practical application in feed production because there are no suitable producers sufficient for its biotechnological production compared to the PhyA and PhyC class ones. Moreover, in most cases, the technologies with the enzymes produced in secretory form are preferable for the production of phytases, though upon microencapsulation in yeast-producing cells, the phytase thermal stability increases significantly compared to the extracellular form, which improves its compatibility with spray drying technology. In this study, we assayed the intracellular heterologous expression of PhyD phytase from Bacillus species in the Yarrowia lipolytica yeast cells. While the technology has been successfully used to synthesize PhyC phytase from Obesumbacterium proteus, PhyD phytase tends to aggregate upon intracellular accumulation. Furthermore, we evaluated the prospects for the production of encapsulated phytase of the PhyD class of high enzymatic activity when it accumulates in the cell cytoplasm of the Y. lipolytica extremophile yeast, a highly effective platform for the production of recombinant proteins. Full article

Yeast biomass, a by-product of various industrial processes, is a sustainable source of food ingredients. Despite its nutritional richness, studies on Yarrowia lipolytica W29 biomass for high-value compound production using low-cost substrates like glycerol and glucose remain limited. These substrates enhance productivity and modulate cell wall composition. Extracting these compounds is complex but can be optimized through sequential hydrolysis, including autolysis and acid hydrolysis. In this study, mannoprotein exhibited a 60% emulsification index, 40 mN m⁻¹ surface tension for both substrates, and thermal stability with a mass retention above 30%. Acid hydrolysis yielded bioactive peptides (<1 kDa) with the highest antioxidant activity: 220 µM Trolox (ABTS), 270 µM Trolox (DPPH), and 125 µM ascorbic acid (FRAP). The raw biomass and feed ingredient (dry residue) provided 100% and 90% of the daily protein intake, respectively, with a β-glucan content of 17%. Glycerol and glucose resulted in similar high-value compounds, highlighting glycerol as a cost-effective carbon source. Thus, sequential hydrolysis is an effective strategy for extracting compounds from Y. lipolytica W29 biomass, offering a promising alternative for industrial applications due to its high nutritional value and functional properties. Full article

This study investigated the capabilities of Yarrowia lipolytica strains to grow in media with different hydrophobic wastes from the meat industry. The yeast growth, cellular lipid accumulation, production of lipases, and degree of utilization of liquid and solid lipid wastes were studied in shaken cultures in media with organic and inorganic nitrogen sources. The effects of the type of waste, initial concentration of carbon source, Yarrowia strain, and inoculum size were investigated in two experimental sets using the Latin Square 5 × 5 design method. Post-frying rapeseed oil from chicken frying was selected as the carbon source to promote biomass growth. In contrast, the solid lipid fraction from meat broths promoted efficient lipid accumulation and yeast lipolytic activity. An initial concentration of the carbon source at 8% m/v stimulated efficient lipid biosynthesis and lipase production, while 2.5% v/v inoculum provided optimal conditions for the growth and utilization of hydrophobic substrates. No significant differences were observed in the particle dispersion of the liquid and solid wastes in the culture media (span = 2.51–3.23). The maximum emulsification index (62%) was observed in the culture of the Y. lipolytica KKP 323 strain in the medium with post-frying rapeseed oil from chicken frying, which was correlated with biosurfactant synthesis. It was concluded that the type of waste, its structure, and its composition affected various physiological yeast responses. Full article

The use of bakery leftovers as a substitute for malt in brewing represents a sustainable approach that reduces costs and waste. In this paper, the fermentation of brewer’s spent grain, a byproduct of beer production, is integrated with the use of non-conventional yeasts to unlock the potential of yeasts beyond the common Saccharomyces species. This creates a circular system where byproducts are efficiently utilized, fostering sustainability and innovation in food production. This study assesses the fermentative capabilities of the non-conventional yeast Yarrowia lipolytica and the lactic acid bacterium Lactobacillus acidophilus DSM 20079 on brewer’s spent grain, a byproduct from brewing beer with old wheat bread and barley malt. Both hydrolyzed with a cell-wall-degrading enzyme complex and non-hydrolyzed brewer’s spent grain were evaluated for key fermentation indicators such as the number of microbial cells, total titratable acidity, pH, reduced sugar content, and fatty acid composition. The findings reveal that Yarrowia lipolytica effectively fermented brewer’s spent grain without prior hydrolysis, maintaining a balanced fatty acid profile. The combined action of both microorganisms provided optimal fermentation outcomes, offering a promising approach for valorizing brewer’s spent grain, reducing waste, and promoting a circular economy in the brewing and food industries. Full article

Lipases are enzymes of great application importance in the food industry, in the cosmetic and detergent industries, in pharmacy and medicine, and in organic chemistry. Among lipases of various origins, those from microorganisms are currently the most commonly used. An excellent producer of lipases seems to be the nonconventional Yarrowia lipolytica yeast, but the biosynthesis of valuable metabolites depends on many factors. This study aimed to investigate the biodiversity of extracellular enzymes produced by four strains of Y. lipolytica, and to determine the optimal conditions of catalysis for the enzymes, according to temperature and pH, in a model hydrolysis reaction. Based on the obtained results, the biodiversity and strain dependence in lipase biosynthesis were observed. Using a Central Composite Design, it was found that temperature is the main factor in determining lipase activity. The enzymes produced by four different strains exhibited other substrate specificity, which was investigated using Latin square design methodology. Only two examined yeast strains, KKP 379 and W29, produced extracellular lipases at a high activity level towards medium- and long-chain fatty acid esters. Moreover, extracellular lipase from wild-type strain KKP 379 was further characterized, followed by exploring the activity of whole-cell biocatalyst and lyophilized enzyme solutions, and it was acknowledged that it was a “true” lipase with the highest affinity to p-nitrophenyl oleate. Full article

Currently, the yeast Yarrowia lipolytica is regarded as one of the most promising producers of protein, lipids, polyols, organic acids, and other metabolites. The objective of enhancing the efficiency of the target product biosynthesis can be achieved through the improvement of the strains-producers and the optimization of the cultivation conditions. The present review assesses the potential of continuous cultivation methods (chemostat, turbidostat, pH-auxostat, changestats, etc.) in order to gain insight into the impact of strains and cultivation conditions on the productivity of the developed bioprocesses. The utilization of continuous cultivation methods enables the implementation of processes under controlled and reproducible conditions, thus stabilizing the parameters of the cultivation and the physiological state of the producer, and obtaining homogeneous samples. The review focuses on nitrogen-limited chemostat cultures, which represent the most commonly employed strategy for investigating the physiological and biochemical characteristics of the yeast Y. lipolytica and for developing the processes for the production of lipids, erythritol, citric acid, and recombinant proteins. To date, such an analysis of the literature has not been conducted in the context of the yeast Y. lipolytica. Full article

The species Yarrowia lipolytica is an aerobic yeast that produces different lipase isoforms, including extracellular, intracellular, and membrane-bound ones. The immobilization of lipases, such as those from Y. lipolytica, increases enzyme stability and lowers operational costs, through its reuse. The characterization of those biocatalysts is highly important to orientate their technological applications. The present work aims to obtain different Y. lipolytica lipases, through fermentation and immobilization techniques, and to evaluate the ester synthesis and hydrolysis activity of these biocatalysts in comparison to a commercial lipase produced by Candida rugosa and test them for phytosterol ester production. High immobilization yield was achieved by microencapsulating Y. lipolytica lipase extract on magnetic nanoparticles (>99.7%). However, immobilization significantly reduced their activity (more than 90%). Lipases from Y. lipolytica showed greater 4-nitrophenyl laurate synthesis in relation to the lipase from C. rugosa. However, C. rugosa lipase was still the best biocatalyst for β-sitosterol oleate synthesis, with a conversion of more than 99%. Y. lipolytica lipases can be good catalysts for ester hydrolysis reactions, even for ester synthesis, but are not good catalysts specifically for phytosterol esters synthesis. Full article

Enzyme immobilization is a crucial method in biotechnology and organic chemistry that significantly improves the stability, reusability, and overall effectiveness of enzymes across various applications. Lipases are one of the most frequently applied enzymes in food. The current study investigated the potential of utilizing selected agri-food and waste materials—buckwheat husks, pea hulls, loofah sponges, and yerba mate waste—as carriers for the immobilization of Sustine^® 121 lipase and Yarrowia lipolytica yeast biomass as whole-cell biocatalyst and lipase sources. Various lignocellulosic materials were pretreated through extraction processes, including Soxhlet extraction with hexane and ethanol, as well as alkaline and acid treatments for loofah sponges. The immobilization process involved adsorbing lipases or yeast cells onto the carriers and then evaluating their hydrolytic and synthetic activities. Preparations’ activities evaluation revealed that alkaline-pretreated loofah sponge yielded the highest hydrolytic activity (0.022 U/mg), while yerba mate leaves under brewing conditions demonstrated superior synthetic activity (0.51 U/mg). The findings underscore the potential of lignocellulosic materials from the agri-food industry as effective supports for enzyme immobilization, emphasizing the importance of material selection and pretreatment methods in optimizing enzymatic performance through giving an example of circular economy application in food processing and waste management. Full article

Polyphenols are powerful natural antioxidants with numerous biological activities. They change cell membrane permeability, interact with receptors, intracellular enzymes, and cell membrane transporters, and quench reactive oxygen species (ROS). Yarrowia lipolytica yeast, being similar to mammalian cells, can be used as a model to study their survival ability upon long-lasting cultivation, assaying the effect of dihydroquercetin polyphenol (DHQ). The complex assessment of the physiological features of the population assaying cell respiration, survival, ROS detection, and flow cytometry was used. Y. lipolytica showed signs of chronological aging by eight weeks of growth, namely a decrease in the cell number, and size, increased ROS generation, a decrease in colony-forming unit (CFU) and metabolic activity, and decreased respiratory rate and membrane potential. An amount of 150 µM DHQ decreased ROS generation at the 6-week growth stage upon adding an oxidant of 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH). Moreover, it decreased CFU at 1–4 weeks of cultivation, inhibited cell metabolic activity of the 24-h-old culture and stimulated that on 14–56 days of growth, induced the cell respiration rate in the 24-h-old culture, and blocked alternative mitochondrial oxidase at growth late stages. DHQ serves as a mild pro-oxidant on the first day of age-stimulating anti-stress protection. In the deep stationary stage, it can act as a powerful antioxidant, stabilizing cell redox status and reducing free radical oxidation in mitochondria. It provides a stable state of population. The hormetic effects of DHQ using lower eukaryotes of Y. lipolytica have been previously discussed, which can be used as a model organism for screening geroprotective compounds of natural origin. Full article