Yeast Oil Research Articles

The effect of non‐marine vs. marine sources of the omega‐3 fatty acids, DHA and EPA, on serum lipoproteins

Fish oil (FO) is a marine source of omega‐3 fatty acids, eicosapentaenoic acid (EPA) and docosahexanaenoic acid (DHA), and has been shown to improve heart health. Our objective was to determine the cardiovascular effects of non‐marine sources, algae oil (AO) and yeast oil (YO), as compared to fish oil (FO). Male ICR mice (8‐wk, n=100) were randomly assigned to dietary groups: soy oil (SO) (no DHA or EPA), FO (DHA + EPA), AO (DHA), YO (EPA), or AO+YO (DHA + EPA) for 2 or 4 wk. Serum triglycerides (TG), total cholesterol (TC), and HDL‐cholesterol were measured and non‐HDL cholesterol (NHDLC) was calculated. Liver DHA and EPA concentration were determined. The FO diet lowered all fractions of plasma lipids and was the only diet to reduce TG (p<0.05). YO, alone and in combination with AO, reduced TC and NHDLC at 4 wks. At 2 wk, AO reduced TC and NHDLC (p<0.05). The AO and AO+YO‐fed mice incorporated less DHA into liver lipids compared to the FO‐fed mice at 2 wk (p<0.05). There were no differences in the incorporation of EPA. Therefore, non‐marine sources do not appear to be as effective as FO at reducing serum lipids.

Expression of transcription factors involved in lipid metabolism in mice fed algae, yeast, or fish oil

Fish oil (FO) contains high levels of the omega‐3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), unlike algae oil (AO) which contains DHA but not EPA, and yeast oil (YO) which contains EPA but not DHA. AO, fed at equal DHA levels, and YO fed at equal EPA levels, were not as effective as FO at reducing body fat or serum lipids. Our objective was to identify transcription factors with altered mRNA expression in the liver of mice fed 12% lipid diets containing either soy oil (SO; no DHA or EPA), FO, AO, YO, or AO+YO for either two or four weeks. The RNA was extracted, reverse transcribed, and amplified with primers for SREBP‐1c, PPAR‐γ, and PPAR‐α. The expression of a long‐chain PUFA receptor, GPR‐120, was also measured. The only difference detected was a trend (P = 0.10) for FO‐fed mice to have increased GPR‐120 expression following 4 weeks of diet consumption. Therefore, the GPR‐120 receptor may be involved in the lipid‐lowering effects of FO.

Absorption of Marine vs Non‐Marine sources of EPA and DHA

DHA from algae oil has been incorporated into tissues at a lower level and been less effective than fish oil (FO) at reducing body fat. Our objective was to determine the fecal excretion of EPA and DHA from different sources. Male mice (n=100) were fed a 12% lipid diet with soy oil (SO), FO, yeast oil (YO, equal EPA to FO diet), algae oil (AO, equal DHA to FO diet), or AO+YO (equal EPA + DHA as FO diet). For 4 weeks fecal samples were collected over night once per week. There were no differences in feed intake, body weight, or body fat (P>;0.05). FO‐fed mice did have heavier livers (P<0.05). AO+YO‐fed mice had greater fecal DHA content than AO‐fed mice and FO‐fed mice for the first 3 weeks (P<0.05) and AO‐fed mice had greater (P<0.05) fecal DHA content than FO‐fed mice in weeks 2–4. FO‐fed mice had greater fecal EPA than YO‐fed mice and AO+YO‐fed mice on week one (P<0.05). FO‐fed mice and YO‐fed mice had greater fecal EPA on week 1 than weeks 2–4 (P<0.05). Thin layer chromatography was performed and verified that the oil sources were primarily composed of triglycerides. In conclusion DHA in FO appears to be more bioavailable than in AO.

Biodiesel production from a newly isolated Pichia kudriavzevii strain

The present report describes the isolation of oleaginous yeast, Pichia kudriavzevii MTCC 5493, from rotten fruits and the production of biodiesel from the yeast oil. Optimization of physiological and nutritional parameters was carried out for improved biomass production using cheap substrates such as crude glycerol, yeast autolysate and corn steep liquor. Fed-batch fermentation yielded a dry biomass and oil yield of up to 33gL−1 and 19% (w/w) respectively and was scaled up successfully to 26L. Optimization of the C/N ratio further increased the oil yield to 23% (w/w). The oil extraction process was also optimized using environmentally safe solvents. The oil profile indicated a high oleic acid content followed by palmitic, linoleic acid, and stearic acid. The presence of increased levels of saturated and monounsaturated fatty acids in the oil make it ideal for biodiesel.

Extraction of lipids from Yarrowia Lipolytica

AbstractBACKGROUND: Microorganisms have often been considered for the production of oils and fats as an alternative to agricultural and animal resources. Extraction experiments were performed using a strain of the yeast Yarrowia lipolytica (Y. lipolytica), a high‐lipid‐content yeast. Three different methods were tested: Soxhlet extraction, accelerated solvent extraction (ASE) and supercritical carbon dioxide (SCCO2) extraction using ethanol as a co‐solvent. Also, high pressure solubility measurements in the systems ‘CO2 + yeast oil’ and ‘CO2 + ethanol + yeast oil’ were carried out.RESULTS: The solubility experiments determined that, at the conditions of the supercritical extractor (40 °C and 20 MPa), a maximum concentration of 10 mg of yeast oil per g of solvent can be expected in pure CO2. 10% w/w of ethanol in the solvent mixture increased this value to almost 15 mg of yeast oil per g of solvent. Different pretreatments were necessary to obtain satisfactory yields in the extraction experiments. The Soxhlet and the ASE method were not able to complete the lipid extraction. The ‘SCCO2 + ethanol’ extraction curves revealed the influence of the different pretreatments on the extraction mechanism.CONCLUSION: Evaluating the effectiveness of a given pretreatment, ASE reduced the amount of material and solvent used compared with Soxhlet. In all three cases, the best total extraction performance was obtained for the ethanol‐macerated yeast (EtM). Addition of ethanol to the solvent mixture enhanced the oil solubility. Oil can be extracted from Y. lipolytica in two different steps: a non‐selective ethanol extraction followed by TAG‐selective SCCO2 purification. © 2012 Society of Chemical Industry

Using Multi-parameter Flow Cytometry to Monitor the Yeast Rhodotorula glutinis CCMI 145 Batch Growth and Oil Production Towards Biodiesel

Multi-parameter flow cytometry was used to monitor cell intrinsic light scatter, viability, and lipid content of Rhodotorula glutinis CCMI 145 cells grown in shake flasks. Changes in the side light scatter and forward light scatter were detected during the yeast batch growth, which were attributed to the different yeast growth phases. A progressive increase in the proportion of cells stained with PI (cells with permeabilized cytoplasmic membrane) was observed during the yeast growth, attaining 79% at the end of the fermentation. A high correlation between the Nile Red fluorescence intensity measured by flow cytometry and total lipid content assayed by the traditional gravimetric lipid analysis was found for this yeast, making this method a suitable and quick technique for the screening of yeast strains for lipid production and optimization of biofuel production bioprocesses. Medium growth optimization for enhancement of the yeast oil production is now in progress.

Heterologous expression of AtClo1, a plant oil body protein, induces lipid accumulation in yeast

Proteomic approaches on lipid bodies have led to the identification of proteins associated with this compartment, showing that, rather than the inert fat depot, lipid droplets appear as complex dynamic organelles with roles in metabolism control and cell signaling. We focused our investigations on caleosin [Arabidopsis thaliana caleosin 1 (AtClo1)], a minor protein of the Arabidopsis thaliana seed lipid body. AtClo1 shares an original triblock structure, which confers to the protein the capacity to insert at the lipid body surface. In addition, AtClo1 possesses a calcium-binding domain. The study of plants deficient in caleosin revealed its involvement in storage lipid degradation during seed germination. Using Saccharomyces cerevisiae as a heterologous expression system, we investigated the potential role of AtClo1 in lipid body biogenesis and filling. The green fluorescent protein-tagged protein was correctly targeted to lipid bodies. We observed an increase in the number and size of lipid bodies. Moreover, transformed yeasts accumulated more fatty acids (+46.6%). We confirmed that this excess of fatty acids was due to overaccumulation of lipid body neutral lipids, triacylglycerols and steryl esters. We showed that the original intrinsic properties of AtClo1 protein were sufficient to generate a functional lipid body membrane and to promote overaccumulation of storage lipids in yeast oil bodies.

Microbial and algal oils: Do they have a future for biodiesel or as commodity oils?

AbstractWe review the prospects of using yeasts and microalgae as sources of cheap oils that could be used for biodiesel. We conclude that yeast oils, the cheapest of the oils producible by heterotrophic microorganisms, are too expensive to be viable alternatives to the major commodity plant oils. Algal oils are similarly unlikely to be economic; the cheapest form of cultivation is in open ponds which then requires a robust, fast‐growing alga that can withstand adventitious predatory protozoa or contaminating bacteria and, at the same time, attain an oil content of at least 40% of the biomass. No such alga has yet been identified. However, we note that if the prices of the major plant oils and crude oil continue to rise in the future, as they have done over the past 12 months, then algal lipids might just become a realistic alternative within the next 10 to 15 years. Better prospects would, however, be to focus on algae as sources of polyunsaturated fatty acids.

Study on passive microwave remote sensing of oil pollution on sea surface

The mixture of five yeast strains obtained from soil could remove about 85% TOC of oil-rich wastewater in batch test. While the highest MLSS was obtained at an N:C of 1:5, the oil removal decreased with the increase of N:C during yeast sludge cultivation. Ammonium chloride was the best nitrogen source for yeast cultivation from the viewpoint of yeast growth and oil utilization. An ammonia concentration of over 1300 mg/L led to mass death of yeast at a pH of 5. The ammonia concentration should be controlled at a level of 1000 mg/L or lower.

Comparison of rotifer culture quality with yeast plus oil and algal-based cultivation diets

The culture quality of rotifers, Brachionus plicatilis, was compared for yeast and algal-based cultivation diets. The rotifer quality was evaluated based on factors which may affect survival and growth of marine fish larvae, including individual length and biomass, nutritional value, bacterial content, and rotifer viability. The diets used were monocultures of Tetraselmis sp., Isochrysis galbana, Pavlova lutheri, and baker's yeast plus capelin oil. Rotifers grown to early stationary phase with equal food rations exhibited equal length distribution, but the rotifer individual biomass was 10–25% higher for yeast-grown rotifers than for algal-grown rotifers. All diets gave equal protein content of individual rotifers. The lipid content was slightly higher and the ratio of protein to lipid was slightly lower with yeast plus capelin oil than with algae. The fatty acid composition of the rotifers was closely related to that of their dietary lipids and the Ω3 fatty acid content was not systematically different for the two types of diets. Use of yeast plus capelin oil resulted in considerably higher numbers of both suspended and rotifer-associated bacteria than with use of algal diets. No differences were found for the algal species involved. The viability of the rotifers in a temperature and salinity test was far better in groups fed algae than in groups fed yeast plus capelin oil. The results indicated an overall better quality of rotifers cultivated with algae than for rotifers cultivated with yeast and oil. Questions related to proteins and the microflora of rotifers should be further emphasized in future research.

Single cell oils — have they a biotechnological future?

Although microorganisms have long been known as producers of edible oils, opportunities for their biotechnological exploitation are limited to the highest-value commodities. A recent attempt to develop a yeast oil cocoa-butter equivalent has not succeeded, not because of the inability to produce the correct formulation of fatty acids, but because of the falling price of cocoa butter on the world market. Better prospects appear to exist for producing polyunsaturated fatty acids (PUFAs) of both the n-6 and n-3 series, using either bacteria, fungi or algae. Many microbial PUFA-oils are characterized by the absence of other PUFAs, making purification of individual fatty acids an easier task than it is from other sources. Certain microorganisms may also produce prostaglandin precursors, or even prostaglandins themselves, as well as cerebroside lipids and other unusual lipids that are not normally regarded as being of microbial origin.

Transformation of vegetable oils by an oleaginous yeast:Rhodotorula glutinis IIP-30

A locally isolated oleaginous yeastRhodotorulaglutinis IIP-30 was grown on vegetable oils obtained from coconut, ground nut and til. The fatty acid composition of yeast oil was quite similar to that of the substrate oil in case of ground nut and til, while it was different with coconut oil. Utilization of C12 and C14 fatty acids of coconut oil to yield higher proportions of C18∶1 and C18∶2 fatty acids was observed.

Biomodification of fats and oils: Trials withCandida lipolytica

AbstractVarious oil‐accumulating yeasts were tested for their ability to produce lipase and live on fats and oils as carbon sources. Of these,Candida lipolytica seemed most promising, and the possibility was explored of modifying fats and oils by fermenting them withC. lipolytica and extracting the modified oil deposited in the yeast cells. Oxygen was required for the growth of yeast on fats and oils, but unless the oxygen level was controlled at a low value after cell populations peaked, most of the substrate oil was converted to citrates rather than accumulating as oil. Oil accumulation byC. lipolytica from a corn oil substrate was slightly depressed by excess nitrogen in the medium. The yeasts were able to use about 18 g/l of oil in 72 hr. At substrate oil levels greater than 18 g/l, the dry yeasts were 60% oil, and about 45–57% of the substrate oil was recovered as yeast oil. The fatty acid composition of the yeast oil was quite similar to that of the substrate oil under optimum conditions of deposition. Sterols, but not tocopherols, were transferred from the substrate to the yeast oil.Candida lipolytica oil was high in free fatty acids. The greatest potential for biomodification by fermentation withC. lipolytica seems to be in altering glyceride structure.

Pigmentation of Egg Yolks with Astaxanthin from the Yeast Phaffia rhodozyma

The red yeast Phaffia rhodozyma was tested as a dietary pigment source for egg yolks of laying hens and Japanese quail. It was found that astaxanthin from broken yeast or prepared yeast oil but not from intact yeast cells was deposited in egg yolks. The efficiency of carotenoid deposition was approximately 4%, and it was only slightly dependent of the astaxanthin concentration in the diet. Astaxanthin was probably deposited without metabolic alteration in egg yolks. When P. rhodozyma was fed to laying hens at several concentrations and in combination with marigold flower pigments or yellow corn, a wide range of colors was achieved; depending on the yeast concentration in the feed, the dominant wavelength of chicken egg yolks ranged from 571 nm to 593 nm.

The Value of the Addition of Fresh Bakers’ Yeast to a Normal Ration for Lactating Dairy Cows

Numerous feeding trials have been conducted in this country and in Europe on the nutritional value of yeast. However, the results of experiments with yeast in the rations of domestic animals have not been consistent because of differences in the kind of yeast, the class of experimental animals, and feeding practices. Bunger (3) found that the digestibility of the protein o f wood sugar yeast was equal to that of crude extracted soybean oil meal; and that yeast and soybean oil meal were of equal value for milk production, per kilogram of crude protein consumed. Barton, Ness, and Crampton (1) concluded that dried brewers' yeast could be substituted for linseed meal pound for pound in the rations of dairy cows. Kranss and Hunt (5) fed dried yeast to dairy cows in amounts up to three-quarters of a pound per cow per day, and found no increase in the vitamin B content of the milk although there was some indication that riboflavin was slightly increased. Golf and Seeling (4) showe~ that feeding irradiated and non-irradiated yeast to dairy cows had no effect on the amount or fat content of the milk produced. Bilek and Hynek (2) obtained an increase in milk production with no change in the fat content when irradiated yeast was added to the winter ration of dairy cows, but when the cows were fed ample supplies of fresh fodder, the effect was no longer present. Lucadou (6) fed 5 grams of living bakers' yeast to dairy cows which resulted in an increased fat test, but milk production remained unchanged. The same quantity of dried living brewers' yeast provedunpalatable and had no effect on either the amount of milk produced or the fat test. Feeding 50 rag. of vitamin BI, or 6 rag. of vitamin B2 separately failed to ~ve positive results. However, when 20 rag. of B1 and 6 nag. of B~ were fed together, this investigator noticed a distinct rise in the fat content of the milk. Under winter feeding conditions, ten times as much vitamin B1 and B2 were required to give the response obtained with cows on pasture.

Effect of Meat Extract on Fatty Infiltration of Liver in Depan-creatized and Duct-Ligated Dogs

Since Fisher1 and Allan, et al.,2 first reported fatty infiltration of the livers in depancreatized dogs maintained on insulin, the observation has been confirmed repeatedly.3 Recently, it has been shown in this4 and other5, 6 laboratories that ligation of the external pancreatic ducts results in similar fatty changes in the liver. In all of these studies the diet fed to the dogs consisted largely of raw whole meat and glucose.In the experiments reported here a dried meat powder preparation,∗ from which the extractives had been removed, was substituted for the whole meat. The diet contained meat powder, cracker meal, milk powder, salts, brewer's yeast, bone ash, cod liver and corn oil. As shown in Table I, little or no fatty infiltration of the liver occurred in 6 depancreatized and in 3 ductligated dogs which were fed the diet for periods varying from 6.5 to 19 weeks after operation. The fatty acid content of the whole livers, determined as previously described,7 averaged 6.2% with a range of 3.12 to 10....

The Role of Proteins in Growth, Reproduction and Lactation. II. The Influence of Whole Liver on Growth and Lactation.

It was reported1 that second generation albino rats on 2 diets, A and B, containing 15 and 20% liver protein respectively, were unable to nurse their young. The failure of lactation was not caused by a deficiency of vitamins since the administration of increased amounts of yeast and cod liver oil as well as the daily administration of 0.3 cc. of wheat germ oil led to no improvement. The daily administration of 0.5 to 1.0 gm. of dried whole liver (dried in a vacuum at 100°C.) also had no beneficial effect on lactation, where-as 1.5 gm. of raw liver daily enabled the animals (9) to nurse their young successfully, 26 animals (45% of the 57 born) being weaned at 21 days of age. The success of raw liver in imparting the ability to lactate is further demonstrated in that third generation animals (2 males and 4 females on each diet) were considerably heavier than the parent generation had been at the same age, the males remained fertile longer than the second generation males, the females had normal oestrus cycl...

Role of Proteins in Growth, Reproduction and Lactation. I. Beef Liver.

In previous studies of growth and reproduction of white rats on meat diets, whole raw, cooked or cooked and dried tissues have been used. Since the biological differences between such diets might reside not only in the protein but also in the tissue lipids, a series of experiments has been planned in which tissues extracted with alcohol until fat-free form the source of protein.In these preliminary experiments on liver, the protein was fed at 2 levels, 15% (diet A) and 20% (diet B). In addition the diets contained 15% fat (hydrogenated cottonseed oil), 4% salts, 2% agar and starch to make 100%. Yeast and cod-liver oil were administered daily.First generation animals on diet B showed a normal growth rate, while growth on diet A was considerably below normal. Three females on diet A gave birth to 11 litters containing a total of 73 young and 12 litters containing 84 young were born to 3 females on diet B. Lactation was deficient and only 40% of the young were weaned on each diet. The mothers lost considerab...