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Yarrowia lipolytica, the non-conventional yeast capable of high lipogenesis, is a microbial chassis for producing lipid-based biofuels and chemicals from renewable resources such as lignocellulosic biomass. However, the low tolerance of Y. lipolytica against furfural, a major inhibitory furan aldehyde derived from the pretreatment processes of lignocellulosic biomass, has restricted the efficient conversion of lignocellulosic hydrolysates. In this study, the furfural tolerance of Y. lipolytica has been improved by supporting its endogenous detoxification mechanism. Specifically, the endogenous genes encoding the aldehyde dehydrogenase family proteins were overexpressed in Y. lipolytica to support the conversion of furfural to furoic acid. Among them, YALI0E15400p (FALDH2) has shown the highest conversion rate of furfural to furoic acid and resulted in two-fold increased cell growth and lipid production in the presence of 0.4 g/L of furfural. To our knowledge, this is the first report to identify the native furfural detoxification mechanism and increase furfural resistance through rational engineering in Y. lipolytica. Overall, these results will improve the potential of Y. lipolytica to produce lipids and other value-added chemicals from a carbon-neutral feedstock of lignocellulosic biomass.

The biosynthesis of citric acid (CA) and its derivatives is of great interest due to its wide range of applications in various manufacturing sectors. The fungus Aspergillus niger is mainly used for the commercial production of CA, using sucrose and molasses as the primary carbon sources. Since the 1960s, intensive research has been underway to introduce Yarrowia lipolytica yeast as an alternative to traditional fungal technology. This review discusses the practical uses of CA and its derivatives. Also, the challenges and developments that have led to efficient and green CA synthesis technologies using Y. lipolytica are outlined. The nutrient medium requirements and the use of various carbon sources, encompassing pure substrates and industry, agriculture, and food waste are considered. Additionally, the choice and improvement of strain producers, including efficient mutagenesis, genetic modification, and screening methods, are discussed.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on Yarrowia lipolytica yeast biomass as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is the dried and heat‐killed biomass of Yarrowia lipolytica, a yeast species that is widespread in nature and which can be found in the environment as well as in foods. The production process is sufficiently described and does not raise safety concerns. The information provided on the composition of the NF is sufficient and does not raise safety concerns. The applicant proposed to use the NF as a food supplement in the form of capsules, tablets or powder. The target population for the NF is the general population above 3 years of age. The maximum proposed daily use levels are 3 g/day for children from 3 years to less than 10 years of age and 6 g/day thereafter. Taking into account the composition of the NF and the proposed use levels, the consumption of the NF is not nutritionally disadvantageous. No relevant toxicological information was provided. The Panel considers that given the qualified presumption of safety (QPS) status for production purposes of Yarrowia lipolytica and the fact that the production process of the NF does not raise safety concerns, no toxicological studies are needed for the safety assessment of the NF. The Panel concludes that the NF, Yarrowia lipolytica yeast biomass, is safe under the proposed conditions of use.

Glucose–fructose syrups were studied for the first time as a carbon source for the biosynthesis of citric acid (CA) by the yeast Yarrowia lipolytica . The producer Y. lipolytica VKM Y-2373 was selected, and the growth conditions were optimized (syrup concentration, 30 g/L; pH, 6.0; aeration, 20% of saturation). The study found that the concentration of ammonium sulfate in the medium had a significant impact on CA production by Y. lipolytica . The maximum CA production was observed at a concentration of 2 g/L (NH 4 ) 2 SO 4 , while concentrations of 1.5 and 3.0 g/L resulted in a decrease of 12 and 30%, respectively. Under the selected conditions, Y. lipolytica VKM Y-2373 produced 36.7 g/L CA in a medium containing glucose–fructose syrup with 52% glucose and 57.7 g/L CA with syrup containing 92% glucose.

The commercial significance of organic acids is extremely high. Due to their chemical properties, organic acids can be used both as building blocks and as individual compounds with enormous annual production. Traditionally, organic acids are obtained from fossil sources through chemical synthesis. However, the most promising approach is microbial synthesis, which yields a product characterized by high purity and a conformational composition similar to the natural substance. This review presents the latest publications (based on search results from 2020 to the present) on the production of organic acids by the yeast Yarrowia lipolytica. In recent years, the combined efforts of microbiologists, physiologists, biochemical engineers, and biotechnologists have led to increases in the titer, yield, and productivity of well-studied “old” acids (citric, succinic, α-ketoglutaric, etc.), as well as the discovery of “new” acids (adipic, 3-hydroxypropionic, L-malic) previously unexplored in Y. lipolytica. Furthermore, the possibility of using alternative substrates as carbon sources increases the attractiveness of producing organic acids by Y. lipolytica in accordance with the principles of a circular economy. The results described here may be useful to the scientific community and stimulate new research in the field of organic acid production in the near future.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on selenium‐enriched biomass of Yarrowia lipolytica as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is the dried and heat‐killed selenium‐enriched biomass of Y. lipolytica. This yeast species is widespread in nature, can be found in the environment and in foods, and was attributed the qualified presumption of safety (QPS) status for production purposes in 2018, including food and feed products based on biomass of the yeast. The production process, fermentation in the presence of sodium selenite, includes a heat‐killing step of the yeast, resulting in the absence of viable Y. lipolytica in the NF. The maximum total selenium content in the NF is 200 μg Se/g, mainly present as organic selenium compounds. The applicant proposed to use the NF as a food supplement. The target population proposed by the applicant is the general population from 3 years of age onwards, with maximum proposed use levels of 0.2 g/day for children from 3 to 9 years of age and 1 g/day thereafter. The Panel considers that the yeast biomass is not of safety concern at the proposed use levels. The Panel also considers that the selenium provided by the NF is as safe as selenium from other dietary sources. However, the Panel notes that, at the use levels proposed by the applicant, the intake of the NF could, in combination with a background diet high in selenium, lead to total selenium intakes exceeding the UL for selenium in all target population groups, except for children from 7 to 9 years. Furthermore, the Panel considers that newly emerging data warrant a reassessment of the UL for selenium.

Following a request from the European Commission, the EFSA was asked to deliver a scientific opinion on the proposed modification of the terms of the authorisation of the feed additive consisting of a preparation of canthaxanthin (CAROPHYLL® Red 10%), regarding the addition of a new production route, by the yeast Yarrowia lipolytica CBS 146148 and to modify the additive specifications by substituting ethoxyquin by 4.4% butylated hydroxytoluene (BHT) and increasing the limit for dichloromethane to 80 mg/kg. The additive is already authorised as zootechnical feed additive for breeder hens. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded. CAROPHYLL® Red 10% containing canthaxanthin produced by fermentation with Yarrowia lipolytica CBS 146148 is safe for the target species, consumer and environment under the current authorised conditions of use for CAROPHYLL® Red 10%. Regarding user safety, canthaxanthin is not irritant to skin and eyes and unlikely to be a skin sensitiser. No conclusion can be reached on the respiratory sensitisation of canthaxanthin. In the absence of data with the additive CAROPHYLL® Red 10%, no conclusions can be reached regarding the safety of the additive for the user. CAROPHYLL® Red 10%, containing canthaxanthin produced by fermentation with Yarrowia lipolytica CBS 146148, is efficacious in breeder hens at 6 mg/kg complete feed.

Following a request from the European Commission, the European Food Safety Authority was asked to deliver a scientific opinion on the proposed modification of the terms of the authorisation of canthaxanthin, regarding the addition of a new production route, by the yeast Yarrowia lipolytica CBS 146148. The additive is already authorised as sensory feed additive for use in feed for chickens for fattening, minor poultry species for fattening, laying poultry, poultry reared for laying, ornamental fish, ornamental birds and ornamental breeder hens. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concludes that canthaxanthin produced with Yarrowia lipolytica CBS 146148 is considered safe for the target species, the consumer and the environment under the current authorised conditions of use. Canthaxanthin is not an irritant to skin or eyes and it is unlikely to be a skin sensitiser. No conclusion can be reached on the respiratory sensitisation of canthaxanthin. In the absence of data, no conclusions on the safety for the user can be reached for any preparation produced with canthaxanthin. Canthaxanthin produced by fermentation with Y. lipolytica CBS 146148 is efficacious as a colouring agent in feed for chickens for fattening and minor poultry species for fattening, laying poultry and poultry reared for laying, ornamental fish and ornamental birds.

In this study, we first thoroughly assayed the response of the key enzymes of energy metabolism and the antioxidant system in Yarrowia lipolytica yeast at extreme pH. The activity of the tricarboxylic acid cycle enzymes, namely NAD-dependent isocitrate dehydrogenase, aconitate hydratase, NAD-dependent malate dehydrogenase, and fumarate hydratase, NADPH-producing enzymes of glucose-6-P dehydrogenase and NADP-dependent isocitrate dehydrogenase, and the enzymes of the glutathione system was assessed. All the enzymes that were tested showed a significant induction contrary to some decrease in the aconitate hydratase activity with acidic and alkaline stress. It is probable that a change in the enzyme activity in the mitochondria matrix is involved in the regulation of the cellular metabolism of Y. lipolytica, which allows the species to prosper at an extreme ambient pH. It distinguishes it from any other type of ascomycete. A close relationship between the induction of the Krebs cycle enzymes and the key enzymes of the glutathione system accompanied by an increased level of reduced glutathione was shown. The assumption that the increased activity of the Krebs cycle dehydrogenases and promotion of the pentose phosphate pathway at pH stress launches a set of events determining the adaptive response of Y. lipolytica yeast.

The EFSA Panel on Food Additive and Flavourings (FAF Panel) provides a scientific opinion on the safety of a new process to produce steviol glycosides by fermentation of simple sugars using a genetically modified strain of Yarrowia lipolytica (named Y. lipolytica VRM). The manufacturing process may result in impurities different from those that may be present in the other steviol glycosides E 960a‐d, therefore the Panel concluded that separate specifications are required for the food additive produced as described in the current application. Viable cells and DNA from the production strain are not present in the final product. The Panel considered that the demonstration of the absence of kaurenoic acid in the proposed food additive, using a method with a limit of detection (LOD) of 0.3 mg/kg, is adequate to dispel the concerns for potential genotoxicity. Given that all steviol glycosides follow the same metabolic pathways, the Panel considered that the current steviol glycosides would fall within the same group of substances. Therefore, the Panel considered that the already existing data on rebaudioside M and structurally related steviol glycosides are sufficient, and a similar metabolic fate and toxicity is expected for the food additive. The results from the bacterial reverse mutation assay and the in vitro micronucleus assay were negative and indicated absence of genotoxicity from the food additive. The existing acceptable daily intake (ADI) of 4 mg/kg body weight (bw) per day, expressed as steviol equivalents, was considered to be applicable to the proposed food additive. The Panel concluded that there is no safety concern for steviol glycosides, predominantly Rebaudioside M, produced by fermentation using Y. lipolytica VRM, to be used as a food additive at the proposed uses and use levels.