Oleaginous yeasts respond differently to carbon sources present in lignocellulose hydrolysate

Abstract Background Microbial oils, generated from lignocellulosic material, have great potential as renewable and sustainable alternatives to fossil-based fuels and chemicals. By unravelling the diversity of lipid accumulation physiology in different oleaginous yeasts grown on the various carbon sources present in lignocellulose hydrolysate (LH), new targets for optimisation of lipid accumulation can be identified. Monitoring lipid formation over time is essential for understanding lipid accumulation physiology. This study investigated lipid accumulation in a variety of oleaginous ascomycetous and basidiomycetous strains grown in glucose and xylose and followed lipid formation kinetics of selected strains in wheat straw hydrolysate (WSH). Results Twenty-nine oleaginous yeast strains were tested for their ability to utilise glucose and xylose, the main sugars present in WSH. Evaluation of sugar consumption and lipid accumulation revealed marked differences in xylose utilisation capacity between the yeast strains, even between those belonging to the same species. Five different promising strains, belonging to the species Lipomyces starkeyi, Rhodotorula glutinis, Rhodotorula babjevae and Rhodotorula toruloides, were grown on undiluted wheat straw hydrolysate and lipid accumulation was followed over time, using Fourier transform-infrared (FTIR) spectroscopy. All five strains were able to grow on undiluted WSH and to accumulate lipids, but to different extents and with different productivities. R. babjevae DVBPG 8058 was the best-performing strain, accumulating 64.8% of cell dry weight (CDW) as lipids. It reached a culture density of 28 g/L CDW in batch cultivation, resulting in a lipid content of 18.1 g/L and yield of 0.24 g lipids per g carbon source. This strain formed lipids from the major carbon sources in hydrolysate, glucose, acetate and xylose. R. glutinis CBS 2367 also consumed these carbon sources, but when assimilating xylose it consumed intracellular lipids simultaneously. Rhodotorula strains contained a higher proportion of polyunsaturated fatty acids than the two tested Lipomyces starkeyi strains. Conclusions There is considerable metabolic diversity among oleaginous yeasts, even between closely related species and strains, especially when converting xylose to biomass and lipids. Monitoring the kinetics of lipid accumulation and identifying the molecular basis of this diversity are keys to selecting suitable strains for high lipid production from lignocellulose.

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Effects of Interactions within a Three-Membered Microbial Community on the Kinetics of Dual Substrate Removal in Continuous Culture

Water Science & Technology ◽

10.2166/wst.1988.0260 ◽

1988 ◽

Vol 20 (11-12) ◽

pp. 11-16

Author(s):

C. P. Leslie Grady ◽

Yunn-Tzer Lu

Keyword(s):

Community Structure ◽

Microbial Community ◽

Bacterial Community ◽

Continuous Culture ◽

Carbon Sources ◽

Substrate Removal ◽

Kinetics Of ◽

Over Time ◽

Dual Substrate

A bacterial community containing a generalist and two specialists was grown in continuous culture at three dilution rates on a feed containing L-lysine and 2-chlorophenol (2-CP) as the only carbon sources. The lysine degrading specialist maintained stable but oscillatory numbers whereas the generalist declined in number throughout each experiment. The 2-CP degrading specialist initially washed out of the culture, but then increased in number over time. No changes in the effluent lysine and 2-CP concentrations could be correlated with the changes in the community structure.

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Oleaginous yeasts- substrate preference and lipid productivity: a view on the performance of microbial lipid producers

Microbial Cell Factories ◽

10.1186/s12934-021-01710-3 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Pariya Shaigani ◽

Dania Awad ◽

Veronika Redai ◽

Monika Fuchs ◽

Martina Haack ◽

...

Keyword(s):

Fatty Acid ◽

Carbon Source ◽

Wheat Straw ◽

Corn Steep Liquor ◽

Building Blocks ◽

Yeast Fermentation ◽

Oleaginous Yeasts ◽

Yeast Strains ◽

Wheat Straw Hydrolysate ◽

Steep Liquor

Abstract Background Oleaginous yeasts are promising microbial platforms for sustainable, bio-based production of biofuels and oleochemical building blocks. Bio-based residues provide sustainable and cost-effective carbon sources for fermentative yeast oil production without land-use change. Considering the regional abundancy of different waste streams, we chose complex biomass residue streams of marine origin; macroalgae hydrolysate, and terrestrial origin; wheat straw hydrolysate in the presence, and absence of corn steep liquor as a complex nitrogen source. We investigated the biomass and lipid yields of an array of well-described oleaginous yeasts; R. glutinis, T. asahii, R. mucilaginosa, R. toruloides, C. oleaginosus growing on these hydrolysates. Furthermore, their sugar utilization, fatty acid profile, and inhibitory effect of the hydrolysates on yeast growth were compared. For correlative reference, we initially performed comparative growth experiments for the strains on individual monomeric sugars separately. Each of these monomeric sugars was a dominant carbon source in the complex biomass hydrolysates evaluated in this study. In addition, we evaluated N-acetylglucosamine, the monomeric building block of chitin, as a low-cost nitrogen and carbon source in yeast fermentation. Results C. oleaginosus provided the highest biomass and lipid yields. In the wheat straw and brown algae hydrolysates, this yeast strain gained 7.5 g/L and 3.8 g/L lipids, respectively. Cultivation in algae hydrolysate resulted in a higher level of unsaturated fatty acids in the lipids accumulated by all yeast strains. R. toruloides and C. oleaginosus were able to effectively co-utilize mannitol, glucose, and xylose. Growth rates on wheat straw hydrolysate were enhanced in presence of corn steep liquor. Conclusions Among the yeast strains investigated in this study, C. oleaginosus proved to be the most versatile strain in terms of substrate utilization, productivity, and tolerance in the complex media. Various fatty acid profiles obtained on each substrate encourage the manipulation of culture conditions to achieve the desired fatty acid composition for each application. This could be accomplished by combining the element of carbon source with other formerly studied factors such as temperature and oxygen. Moreover, corn steep liquor showed promise for enhancement of growth in the oleaginous strains provided that carbon substrate is available.

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Kinetics of Anti-SARS-CoV-2 Antibody Responses 3 Months Post Complete Vaccination with BNT162b2; A Prospective Study in 283 Health Workers

Cells ◽

10.3390/cells10081942 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1942

Author(s):

Evangelos Terpos ◽

Ioannis P. Trougakos ◽

Vangelis Karalis ◽

Ioannis Ntanasis-Stathopoulos ◽

Sentiljana Gumeni ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Health Workers ◽

Antibody Responses ◽

Healthy Individuals ◽

Younger Age ◽

Constant Rate ◽

Rate Of Decline ◽

A Prospective Study ◽

Kinetics Of ◽

Over Time

The aim of this study was to investigate the kinetics of neutralizing antibodies (NAbs) and anti-SARS-CoV-2 anti-S-RBD IgGs up to three months after the second vaccination dose with the BNT162b2 mRNA vaccine. NAbs and anti-S-RBD levels were measured on days 1 (before the first vaccine shot), 8, 22 (before the second shot), 36, 50, and three months after the second vaccination (D111) (NCT04743388). 283 health workers were included in this study. NAbs showed a rapid increase from D8 to D36 at a constant rate of about 3% per day and reached a median (SD) of 97.2% (4.7) at D36. From D36 to D50, a slight decrease in NAbs values was detected and it became more prominent between D50 and D111 when the rate of decline was determined at −0.11 per day. The median (SD) NAbs value at D111 was 92.7% (11.8). A similar pattern was also observed for anti-S-RBD antibodies. Anti-S-RBDs showed a steeper increase during D22–D36 and a lower decline rate during D36–D111. Prior COVID-19 infection and younger age were associated with superior antibody responses over time. In conclusion, we found a persistent but declining anti-SARS-CoV-2 humoral immunity at 3 months following full vaccination with BNT162b2 in healthy individuals.

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kinetics of anti-SARS-CoV-2 antibodies over time. Results of 10 month follow up in over 300 seropositive Health Care Workers

European Journal of Internal Medicine ◽

10.1016/j.ejim.2021.05.028 ◽

2021 ◽

Author(s):

Jose Felipe Varona ◽

Rodrigo Madurga ◽

Francisco Peñalver ◽

Elena Abarca ◽

Cristina Almirall ◽

...

Keyword(s):

Health Care ◽

Health Care Workers ◽

Care Workers ◽

Kinetics Of ◽

Over Time

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Oleaginous Yeasts as Cell Factories for the Sustainable Production of Microbial Lipids by the Valorization of Agri-Food Wastes

Fermentation ◽

10.3390/fermentation7020050 ◽

2021 ◽

Vol 7 (2) ◽

pp. 50

Author(s):

Antonio Caporusso ◽

Angela Capece ◽

Isabella De De Bari

Keyword(s):

Value Chain ◽

Carbon Sources ◽

Research Progress ◽

Food Wastes ◽

Microbial Lipids ◽

Oleaginous Yeasts ◽

Cell Factories ◽

Side Stream ◽

Versatile Tool ◽

Single Cell Oils

The agri-food industry annually produces huge amounts of crops residues and wastes, the suitable management of these products is important to increase the sustainability of agro-industrial production by optimizing the entire value chain. This is also in line with the driving principles of the circular economy, according to which residues can become feedstocks for novel processes. Oleaginous yeasts represent a versatile tool to produce biobased chemicals and intermediates. They are flexible microbial factories able to grow on different side-stream carbon sources such as those deriving from agri-food wastes, and this characteristic makes them excellent candidates for integrated biorefinery processes through the production of microbial lipids, known as single cell oils (SCOs), for different applications. This review aims to present an extensive overview of research progress on the production and use of oleaginous yeasts and present discussions on the current bottlenecks and perspectives of their exploitation in different sectors, such as foods, biofuels and fine chemicals.

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Influencing the growth kinetics of yeast strains with vitamin supplementation

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/74/1674 ◽

2018 ◽

pp. 113-115

Author(s):

Judit Molnár ◽

Erika Lakatos ◽

Balázs Ásványi

Keyword(s):

Corn Steep Liquor ◽

Cell Mass ◽

Single Cell Protein ◽

Vitamin Supplementation ◽

Cell Protein ◽

Specific Rate ◽

Yeast Strains ◽

Matter Production ◽

Steep Liquor ◽

Kinetics Of

The aim of the current experiment was to optimize the creation process of single cell protein on plant-based substrate solution with the intention to improve end-product turn out by means of adding vitamin solution. Based on the results of the fermentation processes of yeast strains, it was concluded that the vitamin-supplementation produced its greatest effect on the dry matter production, primarily on the K. marxianus DSM 4908 strain, while it was less beneficent when it comes to the figures of wet cell mass. In addition, it can be assumed that vitamin supplementation increased the maximum specific rate of growth (μmax) and decreased the generation time (tg) significantly. In the case of the K. marxianus yeast strain on corn steep liquor treated with vitamin-supplementation, the highest (μmax) and the lowest (tg) data were observed [(0.226 h-1) and (4.4 h), respectively]. Based on the results it was found that K. marxianus DSM 4908 is expedient to be applied on corn steep liquor medium in order to determine its suitability to produce additive for feeding.

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Polyphasic Analysis of Pectinolytic and Stress-Resistant Yeast Strains Isolated From Ivorian Cocoa Fermentation

Journal of Food Research ◽

10.5539/jfr.v4n1p124 ◽

2014 ◽

Vol 4 (1) ◽

pp. 124 ◽

Cited By ~ 2

Author(s):

Lamine Samagaci ◽

Honore G. Ouattara ◽

Bernadette G. Goualie ◽

Sebastien L. Niamke

Keyword(s):

Carbon Metabolism ◽

Incubation Temperature ◽

Starter Culture ◽

Carbon Sources ◽

Stress Conditions ◽

Cocoa Bean ◽

Fermentative Capacity ◽

Yeast Strains ◽

Polygalacturonase Production ◽

Cocoa Fermentation

Microbial preparation containing pectinolytic strains as starter culture should help to standardize cocoa fermentation and reduce the lost due to the variability of cocoa bean. In this study, carbon metabolism, fermentative capacity and effect of environmental conditions on pectinase synthesis were analyzed in four yeast strains previously characterized as highly pectinolytic and stress resistant. The strains showed a restricted carbon metabolism profile with capacity to ferment only glucose and fructose and grown maximally at 5% of these carbon sources. Furthermore, yeasts strains were able to keep round 80% of their relative growth at up to 15% of sugar concentrations and proved to be osmotolerant at 25% glucose. Theses strains expressed their highest fermentative capacity at 35 °C producing up to 10.78 cm3of CO2 and lost more than 50% of this capacity at 40 °C. The isolates studied produced polygacturonase as sole pectinase, optimal production of this enzyme is reached at pH (5-6), at incubation temperature of 30 ºC for strains YS 128, YS 202 and 35 ºC for strains YS 165 and YS 201. However, stress conditions such as 0.5 % acetic acid, 2% lactic acid, 6% citric acid and 6% ethanol repress strongly polygalacturonase production in the strains analyzed. Yeast strains studied present some physiological properties potentially useful for cocoa fermentation but the use of these strains as starter should take into account, the stress conditions susceptible to hinder pectinase production.

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The isocitrate dehydrogenase gene of oleaginous yeast Lipomyces starkeyi is linked to lipid accumulation

Canadian Journal of Microbiology ◽

10.1139/w09-063 ◽

2009 ◽

Vol 55 (9) ◽

pp. 1062-1069 ◽

Cited By ~ 16

Author(s):

Wei Tang ◽

Sufang Zhang ◽

Qian Wang ◽

Haidong Tan ◽

Zongbao Kent Zhao

Keyword(s):

Isocitrate Dehydrogenase ◽

Lipid Accumulation ◽

Oleaginous Yeast ◽

Phylogenetic Analyses ◽

Dry Mass ◽

Strain Engineering ◽

Pcr Analysis ◽

Lipomyces Starkeyi ◽

Intracellular Lipids ◽

Rapid Amplification

The oleaginous yeast Lipomyces starkeyi can accumulate intracellular lipids to over 60% of its cell dry mass under a nitrogen-limited condition. We showed that extracellular and intracellular citrate concentrations of L. starkeyi AS 2.1560 increased and the nicotinamide adenine dinucleotide – isocitrate dehydrogenase (NAD+–IDH) activity decreased at the beginning of the lipid accumulation, suggesting that the attenuation of the NAD+–IDH activity might initiate lipid storage. We next cloned the IDH gene by the methods of degenerate PCR and rapid amplification of cDNA ends. Phylogenetic analyses of the evolutionary relationships among LsIDH1, LsIDH2, and other yeast NAD+–IDHs revealed that the L. starkeyi IDH had a closer relationship with the IDHs of Yarrowia lipolytica . Further real-time PCR analysis showed that the expression levels of both LsIDH1 and LsIDH2 decreased concurrently with the evolution of cellular lipids. Our data should be valuable for understanding the biology of oleaginous yeasts and for further strain engineering of L. starkeyi.

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