Search

The yeast strain Yarrowia lipolytica IPS 21 was tested for its ability to produce the protease enzyme on analytically pure carbon sources as well as on waste carbon sources. It was confirmed that the yeast Y. lipolytica IPS21 can have a higher proteolytic activity in the presence of waste carbon sources in chrome-tanned leather shavings (CTLS) than on yeast extract alone. This is confirmed by the high concentration of amino acids in samples with CTLS, suggesting increased degradation of CTLS by Y. lipolytica or secretion of proteases into the medium. It was also confirmed that metals accumulate mainly in the biomass and not in the supernatant. The biomass was also found to contain high levels of Ca, K and P, which are essential for plant growth. These results show that Y. lipolytica strain IPS21 can be used for the production of extracellular alkaline proteases and for the degradation of protein waste. [ABSTRACT FROM AUTHOR]

The main objective of the study was to develop a concept for the use of oleaginous Yarrowia lipolytica biomass and single-cell oil (SCO) as vegan food components. SCOs were derived from the wild-type strain KKP 379, cultured in media containing glucose, cold-pressed rapeseed oil, and cost-effective carbon sources such as molasses and post-frying rapeseed oil. Confocal microscopy analysis of the biomass and detailed analysis of the composition of fatty acids, sterols, and polycyclic aromatic hydrocarbons (PAHs) in the extracted lipids were conducted. The choice of substrates allowed to obtain SCO from post-frying rapeseed oil medium with the desired yield (3.27 g/L), composition (UFA - 93.34%), and high oxidative stability (Τ max -204.94 min, 120 °C, isothermal conditions). The content of hexane as an extraction solvent was also evaluated, which also complied with European Union requirements (0.0007 mg/kg). All SCOs from Y. lipolytica met the European Commission's requirements for marketed oils and fats for maximum levels of benzo[ a)pyrene and the sum of benzo[ a ]pyrene, benzo[ a ]anthracene, benzo[ b ]fluoranthene and chrysene. The content of benzo[ a ]pyrene was in the range of 0.52–1.71 μg/kg. Finally, the oleaginous yeast biomass was subsequently applied as an enrichment additive in plant-based analogs of Camambert-type cheese, and its potential for use in fat-rich vegan food products was discussed. [ABSTRACT FROM AUTHOR]

Nowadays, the non-conventional yeast Yarrowia lipolytica has become more useful in the field of biotechnology and its environmental applications, since it contains an excellent enzyme system that enables it to degrade and assimilate a wide range of substrates. Therefore, single-cell oil production that can potentially be used as a supplier of functional oils and/or biodiesel could be coupled with the use of hydrophobic waste, as a low-cost culture medium. In the current study, we were interested to investigate the potential of yeast Y.lipolytica L2 KF156787 with different carbon substrates, especially, to study its ability to degrade oils waste and single-cell oil production. The strain showed a high ability to grow on different carbon substrates, accumulate lipids, and efficiently decolorize the black dye (about 90%) in the presence of olive-mill waste, suggesting its feasibility and suitability for bioremediation of hydrophobic wastes with the simultaneous production of lipid-rich biomass. The profiles of fatty acids were not strictly dependent on carbon substrates but also on the strain, which it showed a clear biomodification effect on the substrates lipids used to a higher degree. Most of the fatty acids of the microbial lipid were unsaturated and corresponded mainly to oleic, and linoleic acids, making Y. lipolytica L2 KF156787 valuable from a nutritional point of view. Consequently, strain can be considered as a good tool for integration into bioremediation solutions that realize the requisites of the circular economy and of environmental sustainability. [ABSTRACT FROM AUTHOR]

Yarrowia lipolytica as an oleaginous yeast is capable of growing in various non-conventional hydrophobic substrate types, especially industrial wastes. In this study, the content of thiamine (vitamin B1), riboflavin (vitamin B2), pyridoxine (vitamin B6), biotin (vitamin B7) and folic acid (vitamin B9) in the wet biomass of Y. lipolytica strains cultivated in biofuel waste (SK medium), compared to the standard laboratory YPD medium, was assessed. Additionally, the biomass of Y. lipolytica A-101 grown in biofuel waste (SK medium) was dried and examined for B vitamins concentration according to the recommended microbial methods by AOAC Official Methods. The mean values of these vitamins per 100 g of dry weight of Y. lipolytica grown in biofuel waste (SK medium) were as follows: thiamine 1.3 mg/100 g, riboflavin 5.3 mg/100 g, pyridoxine 4.9 mg/100 g, biotin 20.0 µg/100 g, and folic acid 249 µg/100 g. We have demonstrated that the dried biomass is a good source of B vitamins which can be used as nutraceuticals to supplement human diet, especially for people at risk of B vitamin deficiencies in developed countries. Moreover, the biodegradation of biofuel waste by Y. lipolytica is desired for environmental protection. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Despite many studies, the "check points" of metabolic regulation of citric acid (CA) secretion by the yeasts Y.lipolytica still remain unknown. In this manuscript, some possible aspects of strain dependent secretion as well as CA metabolism regulation were discussed. Keys enzymes' activities, substrate concentration, affinity of the uptake systems, intracellular CA concentration and strains abilities were the main points taken into consideration. The direction for the future studies emerged from this review, mainly connected to cellular and mitochondrial citrate transport systems and cellular substrates transporters (glucose, fructose, glycerol, ethanol and acetate), give promising starting point for future efficient strain development. [ABSTRACT FROM AUTHOR]

Squalеnе is a natural organic compound and tritеrpеnе sourcеd primarily from shark livеr oil. Squalеnе plays a crucial rolе in thе synthеsis pathway of all stеrols. It is widely used in nutritional, therapeutical, and cosmеtic applications. Thе еxtraction of squalеnе from sharks has raisеd еnvironmеntal concеrns duе to thе dеclinе in shark populations. Consеquеntly, thеrе has bееn a shift towards using vegetable oil-based squalene, which, howеvеr, yiеld lowеr productivity. Givеn thе divеrsity of applications for squalеnе and its growing dеmand, thеrе is a prеssing nееd to discovеr cost-еffеctivе and sustainablе altеrnativеs for squalеnе production. Yarrowia lipolytica , a non-convеntional yеast, has gained attention as a promising microbial platform for squalеnе production duе to its natural ability to accumulatе lipids. This review presents an analysis of the metabolic engineering strategies employed upstream and downstream of cultivation parameters in Y. lipolytica to enhance squalene production. It sheds light on recent advancements and prospects in this field. By addressing challenges and highlighting opportunities, we aim to provide insights into the potential of Y. lipolytica as a key factor in the sustainable production of squalene. [Display omitted] • Yarrowia lipolytica is a model microorganism for squalene production. • Metabolic engineering approaches in Y. lipolytica for squalene production are presented. • The upstream and downstream cultivation parameters for improving squalene synthesis were discussed. • Recent advances in microbial production of squalene are summarized. [ABSTRACT FROM AUTHOR]

This study investigates the use of a Yarrowia lipolytica strain for the bioconversion of syngas-derived acetic acid into β-carotene and lipids. A two-stage process was employed, starting with the acetogenic fermentation of syngas by Clostridium aceticum , metabolising CO, CO 2 , H 2 , to produce acetic acid, which is then utilized by Y. lipolytica for simultaneous lipid and β-carotene synthesis. The research demonstrates that acetic acid concentration plays a pivotal role in modulating lipid profiles and enhancing β-carotene production, with increased acetic acid consumption leading to higher yields of these compounds. This approach showcases the potential of using one-carbon gases as substrates in bioprocesses for generating valuable bioproducts, providing a sustainable and cost-effective alternative to more conventional feedstocks and substrates, such as sugars. • Syngas can be used as feedstock for producing lipids and β-carotene. • Y. lipolytica showed efficient conversion of acetic acid from syngas bioconversion. • High β-carotene production was observed with acetic acid from syngas valorization. • Syngas has eco-friendly potential for industrial production of biobased products. [ABSTRACT FROM AUTHOR]

Abstract Laccases are used in decolorization and biodegradation of synthetic dyes, bioremediation of industrial wastewaters and delignification of lignocellulosic compounds. The aims of the present study were the optimization of a recombinant laccase production in Yarrowia lipolytica yeast using sucrose as a main carbon source, and the application of the resulting enzyme to decolorization of synthetic dyes, which are problematic environmental pollutants. Taguchi's experimental design method was employed to optimize medium compounds. Recombinant laccase production by Y. lipolytica YL4 strain increased to 900 U L−1 after optimization of sucrose, ammonium chloride, yeast extract and thiamine levels in the modified PPB medium. Furthermore, the production rate reached 6760 U L−1 in a 5 L bioreactor which represents 4.5- and 33.5-fold increases compared to cultures that were in shake-flask with optimized and primary media, respectively. The supernatant containing secreted recombinant laccase was applied for decolorization of seven dyes. The effects of pH, the amount of enzyme and incubation period were verified. The effect of incubation time on dye decolorization by recombinant laccase was important, which has an influence of greater extent than 90% after 48 h for all dyes. The Trametes versicolor laccase can be efficiently produced in Y. lipolytica and the recombinant enzyme has a considerable potential in the decolorization of pollutant synthetic dyes. Highlights • Sucrose used for laccase production by a recombinant strain of Yarrowia lipolytica. • Increase laccase production up to 30-fold by Taguchi's method and bioreactor cultivation. • Optimization of cost-effective medium to heterologous proteins production by Y. lipolytica. • The recombinant laccase efficiently decolorized synthetic dyes more than 90% after 48 h. [ABSTRACT FROM AUTHOR]

Biodiesel is an alternative diesel fuel, which can be synthesised from renewable biological sources. Lipid production using carbon source in wastewater is an emerging process as it purely depends on waste source. In the present study, the ability of Yarrowia lipolytica to accumulate lipids using slaughterhouse wastewater as substrate was investigated. Using raw wastewater as substrate, maximum lipid content (0.43 g/L) and biomass (1.2 g/g) were obtained. Various pre-treatment methods like acid, alkaline, heat, activated carbon and sawdust treatment were performed and two-fold increase in C/N ratio was observed in combined pre-treatment of sawdust with KOH. Using pretreated wastewater, lipid accumulation was enhanced to 32% with lipid content of 0.64 g/L. Results of this study conclude that the pre-treated slaughterhouse wastewater can be employed as a better feedstock for lipid production using Yarrowia lipolytica. [ABSTRACT FROM AUTHOR]

Solid state fermentation is a biotechnological process that allows the utilization of agro-industrial by-products as solid substrates for the growth of microorganisms, including filamentous fungi and yeasts, with the simultaneous production of added value compounds, like enzymes. Oil cakes, such as olive and sunflower cakes, are generated during vegetable oil extraction and have received great interest as solid substrates in SSF processes. In the present work, a 50% (w/w) mixture of olive and sunflower cakes was used as substrate in SSF for lipase production by several strains of Y. lipolytica and Y. divulgata. The strain of Y. lipolytica W29 was the best lipase producer under small scale SSF and studies were conducted to address important factors in scaling-up the process. Different bioreactors were used and the effect of aeration and agitation on lipase production was studied. Higher lipase activity was obtained in tray bioreactors, reaching 85 U/g (dry mass of substrates) after 48 h of SSF, while the operation in a horizontal drum bioreactor favored yeast growth, resulting in the highest yeast biomass production and a delay in lipase maximum activity. The scale-up of SSF for lipase production by Y. lipolytica has been successfully performed, showing that SSF is an interesting and eco-friendly bioprocessing strategy for the valorization of by-products from vegetable oil industries. • The ability of Yarrowia strains to growth and produce enzymes in SSF was assessed. • Scale-up was performed using trays and horizontal drum bioreactors. • Oxygen availability and mixing influence lipase and yeast biomass production. • Higher lipase productivity was attained in tray bioreactors. [ABSTRACT FROM AUTHOR]

The gene encoding for sucrose isomerase from Pantoea dispersa (PdSIase) was successfully displayed on the cell surface of Yarrowia lipolytica , using the cell wall protein Pir1 as an anchor protein. The highest isomaltulose conversion yield of 93 ± 2% was obtained using the displayed PdSIase. The yeast strain displaying PdSIase was stable throughout broad ranges of pH values (4.5–7.0) and temperatures (20–40 °C). In addition, no trehalulose or glucose by-products were detected during the transformation process. The yeast cells remained highly viable in repeated batch operations for 12 cycles, with a high conversion yield of no less than 80%. The results in our study demonstrate that the PdSIase displayed by Y. lipolytica could continuously and efficiently convert sucrose to isomaltulose. [ABSTRACT FROM AUTHOR]

The presence of selected dehydrogenases, including alcohol dehydrogenase (ADH-YL) and aldehyde dehydrogenase (ALDH-YL), inYarrowia lipolyticaJMY 861, and their potential role in flavor synthesis were investigated. The experimental findings showed that using reduced form of nicotinamide adenine dinucleotide (NADH) as cofactor, the ADH-YL activityin vitrowas 6-fold higher than that with reduced form of nicotinamide adenine dinucleotide phosphate (NADPH); however, under the experimental conditions used in this study, an ALDH-YL activity was not detected. Thein situhexanal reduction reaction was found to be instantaneous; however, when the yeast cells suspension was diluted 150 times, the initial relative hexanal concentration was increased by 84.1%. The chromatographic analyses indicated the conversion,in situ, of linoleic acid hydroperoxides (HPODs) into volatile C6-compounds after 60 min of HPODs addition to the yeast cells suspension. An endogenous alcohol dehydrogenase inYarrowia lipolyticaJMY 861 along with the genetically cloned hydroperoxide lyase from green bell pepper. [ABSTRACT FROM PUBLISHER]

Plastic waste accumulation in the environment is an exponentially growing problem that needs to be urgently addressed to avoid the catastrophic damage of terrestrial and oceanic ecosystems. In this work, currently undervalued plastic carbon content was aimed to be exploited by converting it into triglycerides (TGs), following a two-stage approach. Polyethylene (PE) was first treated by hydrothermal processing (HTP) to obtain PE oils that were later used as carbon source for fermentation with Yarrowia lipolytica and transformed into TGs. HTP PE oil obtained at 425ºC for 120 min was found as an optimal carbon source for the biotechnological stage. Under these optimized conditions, 75% of PE mass was transformed into a PE oil that could be used by Yarrowia as carbon source to grow and produce TGs. An oil concentration of 15 g/l in fermentation media in the biotechnological stage improved fermentation performance as well in comparison to 10 g/l concentration: biomass growth and TGs production yield were increased by 130% regarding the control. Thereby, an alternative approach towards turning one of the most widespread plastics as PE into TGs is proposed in this work. [Display omitted] • Polyethylene to triglycerides through a thermochemical-biotechnological procedure. • Yarrowia lipolytica is able to grow with polyethylene oils from hydrothermal processing. • Hydrothermal processing must be adapted to get viable feed for biofermentation. • Both hydrothermal processing and fermentation stages remarkably influence the global performance. [ABSTRACT FROM AUTHOR]

The biosurfactants produced by yeast species belonging to Candida , Rhodotorula and Yarrowia genera present a growing interest due to their applications in food industry, therapeutics, bioremediation and cosmetics. The yeast strain Yarrowia lipolytica CMGB32 was characterized using morpho-physiological observations and PCR-RFLP analysis of the ITS1-5.8S-ITS2 region. The amplicon had 360 bp and the phylogenetic position of Y. lipolytica CMGB32 compared to reference yeast strains was determined by constructing an UPGMA dendrogram based on the Hinf I restriction profiles. After 72 hours of cultivation on Yeast Peptone media supplemented with 1% petroleum, the strain Y. lipolytica CMGB32 showed a high multiplication rate, forming elaborate pseudohyphae and petroleum mini-droplets invaded by yeast cells. The biosurfactant production was estimated using the emulsification index (E 24 ). High values were obtained against toluene (52%), n -hexadecane and n -dodecane. The stability studies showed that the biosurfactants had an increased activity at 4 o C (57%) while the values decreased significantly by the addition of NaCl (27% for a NaCl solution 10%). The antimicrobial assays using cell-free broth containing biosurfactants revealed no activity against seven tested potential pathogen yeast strains. The screening tests showed that Y. lipolytica CMGB32 had good lipolytic activity in the presence of 1% Tween 80. The present study suggests an important biotechnological potential for the strain Y. lipolytica CMGB32. Therefore, our further research will aim the complex characterization of the purified biosurfactants and the study of a possible relation between biosurfactant production and lipase synthesis. [ABSTRACT FROM AUTHOR]

On the basis of initial screening of Yarrowia lipolytica strains, performed in the shake-flasks experiment using a glycerol medium, three strains with different ability of erythritol production were selected. The yield and dynamics of the biosynthesis by chosen strains were examined in bioreactor cultures and the activities of enzymes responsible for glycerol consumption and erythritol synthesis were analyzed during the process. The comparison of relationship between erythritol production ability and activities of the examined enzymes indicated erythrose reductase (ER) as the key enzyme responsible for erythritol overproduction in Y. lipolytica cells grown on glycerol. In the culture, the activity of ER in the effective phase of erythritol biosynthesis reached 0.068-0.248 U mg-1, whereas erythritol production was from 44.7 to 75.9 g L-1 with the yield of 0.31-0.51 g g-1. The cells ability of erythritol formation depended slightly on the glycerol kinase and glycerol-3-phosphate dehydrogenase. [ABSTRACT FROM AUTHOR]

As a promising species of the thraustochytrids, Schizochytrium sp. has attracted extensive attention due to its ability to produce high levels of polyunsaturated fatty acids. In Schizochytrium sp. HX-308, there was a complete anaerobic polyketide synthase (PKS) pathway and an incomplete aerobic desaturase/elongase pathway. However, it is still quite unclear which fatty acid desaturases are involved in fatty acid desaturation in Schizochytrium sp. and how they act in concert. In this work, we firstly identified five putative desaturases in Schizochytrium sp. HX-308, including Δ12, two Δ8, Δ6, and Δ5 fatty acid desaturase genes. They were heterologously expressed in Yarrowia lipolytica and the first four fatty acid desaturases were verified as functional. Δ12 desaturase contributes to a significant increase in the content of C18:2Δ9, 12 fatty acids, from 17.26 % to 28.46 %. The expression of two Δ8 desaturases resulted in an increase in C20:3Δ8, 11, 14 content, from 3.84 % to 7.29 % and 6.82 %, respectively. Δ6 desaturase enables the PO1F strain to produce a new fatty acid C18:3Δ6, 9, 12, reaching 9.73 % of the total fatty acids. Although the expression of Δ5 desaturase didn't produce C20:4 Δ5, 8, 11, 14 fatty acids, it significantly decreased the content of C18:1Δ9 and C18:2Δ9, 12 fatty acids and largely significantly increased C18:3Δ6, 9, 12 and C20:2Δ11, 14 fatty acid content. This work will provide valuable insights into the optimization of the polyunsaturated fatty acid composition of Schizochytrium sp. through genetic engineering in the future. [Display omitted] • Identification and characterization of five fatty acid desaturases in Schizochytrium sp. HX-308. • Heterologous expression of fatty acid desaturases changed the fatty acid profile of Y. lipolytica. • Heterologous expression of fatty acid desaturases enhances the production of PUFAs in Y. lipolytica. [ABSTRACT FROM AUTHOR]

Abstract: Statistical optimization is an effective technique for the investigation of complex processes with minimal number of experimental runs. In this study, statistical approach was used to study the optimization of media components for lipase production from Yarrowia lipolytica MTCC 35. Mahua cake, glucose, MnCl2 and KH2PO4 were screened to be the most significant variables among the nine medium variables that were tested to determine influence on lipase production by Plackett–Burman design. Central Composite Design was used for further optimization of these screened variables for enhanced lipase production. The determination coefficient (R 2) value of 0.922 showed that the regression models adequately explain the data variation and represent the actual relationships between the variables and response. The optimum values of investigated variables for the maximum lipase production were 6.0% Mahua cake, 2.0% glucose, 0.2% MnCl2 and 0.2% KH2PO4. The maximum lipase production (9.40UmL−1) was obtained under optimal condition. [Copyright &y& Elsevier]

The article presents a study that aims at identifying seven chitin synthase-encoding genes in the genome of dimorphic ascomycete yeast Yarrowia (Y.) lipolytica. The study revealed that class II chitin synthase plays an important role in septum formation in Y. lipolytica. It also suggests that class V and VI chitin synthases with myosin motor-like domain (MMD) are involved in the maintenance of cell wall integrity in Y. lipolytica.

The article discusses a study on metabolism of hydrophobic carbon, including normal-alkanes (n-alkanes) and fatty acids, and its transcriptional regulation in the yeast Yarrowia lipolytica. The study informs that hydroxylation of n-alkanes is by cytochromes P450 on endoplasmic reticulum (ER) and oxidation of fatty alcohol is by the enzyme fatty alcohol dehydrogenase (FADH) in ER. It mentions about Activin receptor-like kinase (ALK) 1 involved in transcriptional regulation of Y. lipolytica.

Abstract: γ-Decalactone is an industrially important flavor compound with a peachy aroma which has been approved by FDA as a food additive. The aim of this study was to compare batch and fed-batch cultivation for production of γ-decalactone using Yarrowia lipolytica and castor oil as substrate. Microbial production of γ-decalactone from castor oil using the obligate aerobic yeast Y. lipolytica was investigated in a 3l bioreactor. Batch and fed-batch fermentations were compared for the production of γ-decalactone. Also the effect of enhancing oxygen transfer rate by using higher agitation rates or pure oxygen for aeration was investigated. The highest γ-decalactone concentration (220mg/l) was obtained in the fed-batch fermentation using pure oxygen which was 3-fold more compared to the batch cultivation. Using pure oxygen instead of atmospheric air in the fed-batch fermentation also resulted in 60% increase in γ-decalactone production. [Copyright &y& Elsevier]

Copyright of Biotechnologie, Agronomie, Societe et Environnement is the property of Les Presses Agronomiques de Gembloux and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Microbial lipids are envisaged as promising alternatives for sustainable production of chemicals and fuels. Although sugar-based substrates are the most conventional carbon sources employed for this purpose, the use of low-cost feedstock, such as organic wastes, is crucial for an economically-viable process. In this study, volatile fatty acids (VFAs) obtained during the anaerobic fermentation of food waste were used as carbon sources to produce lipids in Yarrowia lipolytica ACA DC 50109. Different total VFAs concentrations, acids profiles and carbon:nitrogen (C:N) ratios were used in both real digestates and synthetic media to establish the optimal culture conditions for lipid production. Y. lipolytica was able to grow in all cases despite of using concentrations as high as 15 g/L of total VFAs. The highest obtained lipid contents were 43.4% and 37.3% w/w using 15 g/L VFAs, 6:1 acetic:hexanoic ratio and C:N of 200:1 and 150:1, respectively. These lipids contents implied lipid yields of 0.33 g/g and 0.31 g/g, that were very close or even higher than lipid yields reported from sugars. This fact proves the suitability of using VFA derived from wastes as a low-cost carbon sources for the production of lipids and highlights the importance of paying attention to VFAs profile and C:N in the media for an efficient process. [Display omitted] • 15 g/L volatile fatty acid (VFAs) did not inhibit Yarrowia lipolytica growth. • Y. lipolytica growth was boosted in real digestates from food waste. • High concentration of short-chain VFAs promoted lipid accumulation up to 43.4% w/w. • High carbon-to-nitrogen ratio changed yeast metabolism towards lipid production. • Lipid yield from VFAs in real digestate was higher than reported from glucose. [ABSTRACT FROM AUTHOR]

The article presents a study that observes the impact of SCS2 ortholog disruption in the growth of alkane-assimilating yeast Yarrowia lipolytica on n-decane. It examines the transcription of phospholipid biosynthetic genes in Saccharomyces cerevisiae. The study found out that Y1Scs2p is required for the growth of Y. lipolytica on n-decane, but is not involved in the inositol response. Details about inducible cytochrome P450ALK, inositol auxotrophy and ALKI gene are also offered.

Yarrowia lipolytica NCIM 3589, a tropical marine degrader of hydrocarbons and triglycerides transformed 2,4,6-trinitrotoluene (TNT) very efficiently. Though this yeast could not utilize TNT as the sole carbon or nitrogen source, it was capable of reducing the nitro groups in TNT to aminodinitrotoluene (ADNT). In a complete medium containing glucose and ammonium sulphate as the available carbon and nitrogen sources respectively, the culture was able to completely transform 1 mM (227 ppm) of TNT under such conditions. A dual pathway was found to be functional, one of which resulted in the formation of the hydride-Meisenheimer complex (H-TNT) as a transiently accumulating metabolite that was subsequently denitrated to 2,4-dinitrotoluene (2,4-DNT), whereas the other pathway resulted in the formation of amino derivatives. The presence of increasing amounts of reducing equivalents in the form of glucose promoted better growth and the nitroreductases of this yeast to reduce the aromatic ring to 2,4-DNT although, the reduction of the nitro groups to amino groups was the major functional pathway. The ability of this tropical marine yeast to transform TNT into products such as 2,4-DNT which in turn could be metabolized by other microbes has implications in the use of this yeast for bioremediation of TNT polluted marine environments. [Copyright &y& Elsevier]

γ-decalactone is an industrially relevant aroma compound produced by microbial transformation of ricinoleic acid. Low yields of γ-decalactone owing to toxic concentrations of substrate, formation of competing metabolites and its purification are the major concerns for industrial production. Thus, the current study focuses on improving the microbial yields of γ-decalactone using Yarrowia lipolytica NCIM 3590 by optimizing the parameters of biotransformation. Molar conversion of 75% with 5 g/L ricinoleic acid was achieved using 12 g DCW/L. The highest γ-decalactone productivity of 200 mg/L/h was achieved within 10 h at constant agitation and aeration rate of 200 rpm and 2 vvm, respectively using continuous stirred tank reactor (CSTR). The stationary phase cells used for production can be reused for four cycles without loss of productivities. Further, the produced γ-decalactone was isolated and purified from the biotransformation media using a combination of chromatography and liquid-liquid extraction methods. This three-step purification yields 80% pure γ-decalactone with an overall recovery of 85% of the product. The present study can be used for industrial-scale continuous production of γ-decalactone. [Display omitted] • Process optimization for production of γ-decalactone by Yarrowia lipolytica. • Use of optimized conditions to yield 75% molar conversion of 5 g/L ricinoleic acid. • Enhanced γ-decalactone production in Continuous stirred Tank Reactor. • Downstream operation for manufacturing 80% pure γ-decalactone with 85% recovery. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the application of deuterium (D) labeled glucose-D 7 as Raman-tag in Yarrowia lipolytica to assess triacyl glycerides (TAG) biosynthesis. Cells were grown in N depleted media in: (i) glucose in H 2 O (control), (ii) glucose-D 7 in H 2 O and (iii) glucose-D 7 in D 2 O, and the resulting biomass and lipids quantified. Infrared and Raman spectroscopies showed the incorporation of D with the presence of a C-D stretching bands in the silent region (1800–2600 cm−1) for cells grown in glucose-D 7 in H 2 O and glucose-D 7 in D 2 O as compared to the control. Fatty acid methyl ester analysis of cells grown in the three media showed significant differences in lipid profiles. Cells grown on glucose-D 7 in H 2 O and glucose-D 7 in D 2 O showed unequivocally D incorporation in fatty acids and TAG by mass spectrometry. Higher D incorporation was observed when cells were grown in D 2 O than H 2 O. Deuterium was also incorporated into the cell wall polysaccharides. [Display omitted] • Deuterium was incorporated in Yarrowia lipolytica cells that were fed glucose-D 7. • Deuterium was incorporated in both the lipids and cell wall polysaccharides. • Higher levels of D were observed when using D 2 O versus H 2 O. • The lipids and polysaccharides were analyzed by Raman, FTIR, GC-MS and ESI-MS. [ABSTRACT FROM AUTHOR]

• Chlorella pyrenoidesa and Yarrowia lipolytica co-culture was performed. • Under optimized conditions, algal growth and protein content improved. • The protein from co-culture (CY-protein) was larger with a variable structure. • CY-protein showed potent anti-hemolytic activity under oxidative stress. • Yeast-algal symbiotic co-culture has potential for improving bioactive production. We characterized the co-culture system of Chlorella pyrenoidosa and Yarrowia lipolytica to identify co-culture products of high application value. We first optimized the co-culture parameters using different ratios of algae and Y. lipolytica , which highlighted the competitive relationship between the two organisms. Analysis of pH values indicated that a relatively alkaline symbiotic co-culture might result in undetectable amounts of Y. lipolytica. The ratio of C. pyrenoidosa and yeast did not influence the balance of dissolved oxygen, but showed an influence on the production of chlorophyll A and total protein, with the protein content significantly increasing after 5 days of co-culture. Two protein hydrolysates were extracted from a single culture of C. pyrenoidosa and from a co-culture with Y. lipolytica (3:1 ratio) after 5 days. Structure analysis indicated a high molecular weight and composition of antioxidative-associated amino acids in the co-culture protein, and the two spatial structures were quite diverse; the co-culture protein showed formation of side chain vibrations and unordered structures. Notably, Y. lipolytica could stimulate the formation of superoxide dismutase and the chlorophyll a-b binding protein. In contrast to the protein from C. pyrenoidosa single culture, the co-culture protein showed remarkable protective effects on erythrocytes under oxidative stress, which may be attributed to its specific structure. The activities of antioxidative-associated enzymes were significantly lower than those in the control group (without protein), and the contents of oxidation-related metabolic products, including total glutathione, increased, while the glutathione disulfide content decreased significantly. We hypothesize that this C. pyrenoidosa -specific protein structure obtained from co-culture with Y. lipolytica consists of more exposed hydrophobic residues on the surface of protein molecules, resulting in enhanced antioxidative activity. Therefore, the protein from the yeast-algal symbiotic co-culture has a larger variable structure and shows potent anti-hemolytic activity under oxidative stress. [ABSTRACT FROM AUTHOR]